remove extern crate declaration and fix outfall (macros now need to be imported into scope)

using use declarations in main.rs so that use paths don't need to be updated as well, this will be done in a later commit

build.rs

@@ -15,15 +15,13 @@ fn find_prolog_files(libraries: &mut File, prefix: &str, current_dir: &Path) {
     for entry in entries.filter_map(Result::ok).map(|e| e.path()) {
         if entry.is_dir() {
             if let Some(file_name) = entry.file_name() {
-                let new_prefix =
+                let new_prefix = prefix.to_owned() + file_name.to_str().unwrap() + "/";
-                    prefix.to_owned() + file_name.to_str().unwrap() + "/";
                 find_prolog_files(libraries, &new_prefix, &entry);
             }
         } else if entry.is_file() {
             let ext = std::ffi::OsStr::new("pl");
             if entry.extension() == Some(ext) {
-                let contain =
+                let contain = String::from_utf8(fs::read(&entry).unwrap()).unwrap();
-                    String::from_utf8(fs::read(&entry).unwrap()).unwrap();
                 let name = entry.file_stem().unwrap().to_str().unwrap();
 
                 let line = format!(
@@ -47,7 +45,7 @@ fn main() {
 
     libraries
         .write_all(
-            b"ref_thread_local! {
+            b"ref_thread_local::ref_thread_local! {
     pub static managed LIBRARIES: IndexMap<&'static str, &'static str> = {
         let mut m = IndexMap::new();\n",
         )

src/allocator.rs

@@ -1,4 +1,5 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::temp_v;
 
 use crate::fixtures::*;
 use crate::forms::*;
@@ -14,8 +15,13 @@ pub trait Allocator<'a> {
     fn mark_anon_var<Target>(&mut self, _: Level, _: GenContext, _: &mut Vec<Target>)
     where
         Target: CompilationTarget<'a>;
-    fn mark_non_var<Target>(&mut self, _: Level, _: GenContext, _: &'a Cell<RegType>, _: &mut Vec<Target>)
+    fn mark_non_var<Target>(
-    where
+        &mut self,
+        _: Level,
+        _: GenContext,
+        _: &'a Cell<RegType>,
+        _: &mut Vec<Target>,
+    ) where
         Target: CompilationTarget<'a>;
     fn mark_reserved_var<Target>(
         &mut self,
@@ -28,8 +34,14 @@ pub trait Allocator<'a> {
         _: bool,
     ) where
         Target: CompilationTarget<'a>;
-    fn mark_var<Target>(&mut self, _: Rc<Var>, _: Level, _: &'a Cell<VarReg>, _: GenContext, _: &mut Vec<Target>)
+    fn mark_var<Target>(
-    where
+        &mut self,
+        _: Rc<Var>,
+        _: Level,
+        _: &'a Cell<VarReg>,
+        _: GenContext,
+        _: &mut Vec<Target>,
+    ) where
         Target: CompilationTarget<'a>;
 
     fn reset(&mut self);
@@ -47,7 +59,7 @@ pub trait Allocator<'a> {
     fn drain_var_data(
         &mut self,
         vs: VariableFixtures<'a>,
-        num_of_chunks: usize
+        num_of_chunks: usize,
     ) -> VariableFixtures<'a> {
         let mut perm_vs = VariableFixtures::new();
 

src/arithmetic.rs

@@ -1,4 +1,5 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::{atom, clause_name};
 
 use crate::clause_types::*;
 use crate::fixtures::*;
@@ -267,9 +268,7 @@ impl<'a> ArithmeticEvaluator<'a> {
 
     fn push_constant(&mut self, c: &Constant) -> Result<(), ArithmeticError> {
         match c {
-            &Constant::Fixnum(n) => self
+            &Constant::Fixnum(n) => self.interm.push(ArithmeticTerm::Number(Number::Fixnum(n))),
-                .interm
-                .push(ArithmeticTerm::Number(Number::Fixnum(n))),
             &Constant::Integer(ref n) => self
                 .interm
                 .push(ArithmeticTerm::Number(Number::Integer(n.clone()))),
@@ -326,17 +325,11 @@ impl<'a> ArithmeticEvaluator<'a> {
 // integer division rounding function -- 9.1.3.1.
 pub fn rnd_i<'a>(n: &'a Number) -> RefOrOwned<'a, Number> {
     match n {
-        &Number::Integer(_) => {
+        &Number::Integer(_) => RefOrOwned::Borrowed(n),
-            RefOrOwned::Borrowed(n)
+        &Number::Float(OrderedFloat(f)) => RefOrOwned::Owned(Number::from(
-        }
+            Integer::from_f64(f.floor()).unwrap_or_else(|| Integer::from(0)),
-        &Number::Float(OrderedFloat(f)) => {
+        )),
-            RefOrOwned::Owned(Number::from(
+        &Number::Fixnum(n) => RefOrOwned::Owned(Number::from(n)),
-                Integer::from_f64(f.floor()).unwrap_or_else(|| Integer::from(0))
-            ))
-        }
-        &Number::Fixnum(n) => {
-            RefOrOwned::Owned(Number::from(n))
-        }
         &Number::Rational(ref r) => {
             let r_ref = r.fract_floor_ref();
             let (mut fract, mut floor) = (Rational::new(), Integer::new());
@@ -432,31 +425,31 @@ impl Add<Number> for Number {
                     Number::from(Integer::from(n1) + Integer::from(n2))
                 })
             }
-            (Number::Fixnum(n1), Number::Integer(n2)) |
+            (Number::Fixnum(n1), Number::Integer(n2))
-            (Number::Integer(n2), Number::Fixnum(n1)) => {
+            | (Number::Integer(n2), Number::Fixnum(n1)) => {
                 Ok(Number::from(Integer::from(n1) + &*n2))
             }
-            (Number::Fixnum(n1), Number::Rational(n2)) |
+            (Number::Fixnum(n1), Number::Rational(n2))
-            (Number::Rational(n2), Number::Fixnum(n1)) => {
+            | (Number::Rational(n2), Number::Fixnum(n1)) => {
                 Ok(Number::from(Rational::from(n1) + &*n2))
             }
-            (Number::Fixnum(n1), Number::Float(OrderedFloat(n2))) |
+            (Number::Fixnum(n1), Number::Float(OrderedFloat(n2)))
-            (Number::Float(OrderedFloat(n2)), Number::Fixnum(n1)) => {
+            | (Number::Float(OrderedFloat(n2)), Number::Fixnum(n1)) => {
                 Ok(Number::Float(add_f(float_fn_to_f(n1)?, n2)?))
             }
             (Number::Integer(n1), Number::Integer(n2)) => {
                 Ok(Number::from(Integer::from(&*n1) + &*n2)) // add_i
             }
             (Number::Integer(n1), Number::Float(OrderedFloat(n2)))
-          | (Number::Float(OrderedFloat(n2)), Number::Integer(n1)) => {
+            | (Number::Float(OrderedFloat(n2)), Number::Integer(n1)) => {
                 Ok(Number::Float(add_f(float_i_to_f(&n1)?, n2)?))
             }
             (Number::Integer(n1), Number::Rational(n2))
-          | (Number::Rational(n2), Number::Integer(n1)) => {
+            | (Number::Rational(n2), Number::Integer(n1)) => {
                 Ok(Number::from(Rational::from(&*n1) + &*n2))
             }
             (Number::Rational(n1), Number::Float(OrderedFloat(n2)))
-          | (Number::Float(OrderedFloat(n2)), Number::Rational(n1)) => {
+            | (Number::Float(OrderedFloat(n2)), Number::Rational(n1)) => {
                 Ok(Number::Float(add_f(float_r_to_f(&n1)?, n2)?))
             }
             (Number::Float(OrderedFloat(f1)), Number::Float(OrderedFloat(f2))) => {
@@ -474,12 +467,13 @@ impl Neg for Number {
 
     fn neg(self) -> Self::Output {
         match self {
-            Number::Fixnum(n) =>
+            Number::Fixnum(n) => {
                 if let Some(n) = n.checked_neg() {
                     Number::Fixnum(n)
                 } else {
                     Number::from(-Integer::from(n))
                 }
+            }
             Number::Integer(n) => Number::Integer(Rc::new(-Integer::from(&*n))),
             Number::Float(OrderedFloat(f)) => Number::Float(OrderedFloat(-f)),
             Number::Rational(r) => Number::Rational(Rc::new(-Rational::from(&*r))),
@@ -507,16 +501,16 @@ impl Mul<Number> for Number {
                     Number::from(Integer::from(n1) * Integer::from(n2))
                 })
             }
-            (Number::Fixnum(n1), Number::Integer(n2)) |
+            (Number::Fixnum(n1), Number::Integer(n2))
-            (Number::Integer(n2), Number::Fixnum(n1)) => {
+            | (Number::Integer(n2), Number::Fixnum(n1)) => {
                 Ok(Number::from(Integer::from(n1) * &*n2))
             }
-            (Number::Fixnum(n1), Number::Rational(n2)) |
+            (Number::Fixnum(n1), Number::Rational(n2))
-            (Number::Rational(n2), Number::Fixnum(n1)) => {
+            | (Number::Rational(n2), Number::Fixnum(n1)) => {
                 Ok(Number::from(Rational::from(n1) * &*n2))
             }
-            (Number::Fixnum(n1), Number::Float(OrderedFloat(n2))) |
+            (Number::Fixnum(n1), Number::Float(OrderedFloat(n2)))
-            (Number::Float(OrderedFloat(n2)), Number::Fixnum(n1)) => {
+            | (Number::Float(OrderedFloat(n2)), Number::Fixnum(n1)) => {
                 Ok(Number::Float(mul_f(float_fn_to_f(n1)?, n2)?))
             }
             (Number::Integer(n1), Number::Integer(n2)) => {
@@ -549,72 +543,50 @@ impl Div<Number> for Number {
 
     fn div(self, rhs: Number) -> Self::Output {
         match (self, rhs) {
-            (Number::Fixnum(n1), Number::Fixnum(n2)) => {
+            (Number::Fixnum(n1), Number::Fixnum(n2)) => Ok(Number::Float(div_f(
-                Ok(Number::Float(div_f(
+                float_fn_to_f(n1)?,
-                    float_fn_to_f(n1)?,
+                float_fn_to_f(n2)?,
-                    float_fn_to_f(n2)?,
+            )?)),
-                )?))
+            (Number::Fixnum(n1), Number::Integer(n2)) => Ok(Number::Float(div_f(
-            }
+                float_fn_to_f(n1)?,
-            (Number::Fixnum(n1), Number::Integer(n2)) => {
+                float_i_to_f(&n2)?,
-                Ok(Number::Float(div_f(
+            )?)),
-                    float_fn_to_f(n1)?,
+            (Number::Integer(n1), Number::Fixnum(n2)) => Ok(Number::Float(div_f(
-                    float_i_to_f(&n2)?,
+                float_i_to_f(&n1)?,
-                )?))
+                float_fn_to_f(n2)?,
-            }
+            )?)),
-            (Number::Integer(n1), Number::Fixnum(n2)) => {
+            (Number::Fixnum(n1), Number::Rational(n2)) => Ok(Number::Float(div_f(
-                Ok(Number::Float(div_f(
+                float_fn_to_f(n1)?,
-                    float_i_to_f(&n1)?,
+                float_r_to_f(&n2)?,
-                    float_fn_to_f(n2)?,
+            )?)),
-                )?))
+            (Number::Rational(n1), Number::Fixnum(n2)) => Ok(Number::Float(div_f(
-            }
+                float_r_to_f(&n1)?,
-            (Number::Fixnum(n1), Number::Rational(n2)) => {
+                float_fn_to_f(n2)?,
-                Ok(Number::Float(div_f(
+            )?)),
-                    float_fn_to_f(n1)?,
-                    float_r_to_f(&n2)?,
-                )?))
-            }
-            (Number::Rational(n1), Number::Fixnum(n2)) => {
-                Ok(Number::Float(div_f(
-                    float_r_to_f(&n1)?,
-                    float_fn_to_f(n2)?,
-                )?))
-            }
             (Number::Fixnum(n1), Number::Float(OrderedFloat(n2))) => {
-                Ok(Number::Float(div_f(
+                Ok(Number::Float(div_f(float_fn_to_f(n1)?, n2)?))
-                    float_fn_to_f(n1)?,
-                    n2,
-                )?))
             }
             (Number::Float(OrderedFloat(n1)), Number::Fixnum(n2)) => {
-                Ok(Number::Float(div_f(
+                Ok(Number::Float(div_f(n1, float_fn_to_f(n2)?)?))
-                    n1,
-                    float_fn_to_f(n2)?,
-                )?))
-            }
-            (Number::Integer(n1), Number::Integer(n2)) => {
-                Ok(Number::Float(div_f(
-                    float_i_to_f(&n1)?,
-                    float_i_to_f(&n2)?,
-                )?))
             }
+            (Number::Integer(n1), Number::Integer(n2)) => Ok(Number::Float(div_f(
+                float_i_to_f(&n1)?,
+                float_i_to_f(&n2)?,
+            )?)),
             (Number::Integer(n1), Number::Float(OrderedFloat(n2))) => {
                 Ok(Number::Float(div_f(float_i_to_f(&n1)?, n2)?))
             }
             (Number::Float(OrderedFloat(n2)), Number::Integer(n1)) => {
                 Ok(Number::Float(div_f(n2, float_i_to_f(&n1)?)?))
             }
-            (Number::Integer(n1), Number::Rational(n2)) => {
+            (Number::Integer(n1), Number::Rational(n2)) => Ok(Number::Float(div_f(
-                Ok(Number::Float(div_f(
+                float_i_to_f(&n1)?,
-                    float_i_to_f(&n1)?,
+                float_r_to_f(&n2)?,
-                    float_r_to_f(&n2)?,
+            )?)),
-                )?))
+            (Number::Rational(n2), Number::Integer(n1)) => Ok(Number::Float(div_f(
-            }
+                float_r_to_f(&n2)?,
-            (Number::Rational(n2), Number::Integer(n1)) => {
+                float_i_to_f(&n1)?,
-                Ok(Number::Float(div_f(
+            )?)),
-                    float_r_to_f(&n2)?,
-                    float_i_to_f(&n1)?,
-                )?))
-            }
             (Number::Rational(n1), Number::Float(OrderedFloat(n2))) => {
                 Ok(Number::Float(div_f(float_r_to_f(&n1)?, n2)?))
             }
@@ -727,12 +699,8 @@ impl<'a> TryFrom<(Addr, &'a Heap)> for Number {
 
     fn try_from((addr, heap): (Addr, &'a Heap)) -> Result<Number, Self::Error> {
         match addr {
-            Addr::Fixnum(n) => {
+            Addr::Fixnum(n) => Ok(Number::from(n)),
-                Ok(Number::from(n))
+            Addr::Float(n) => Ok(Number::Float(n)),
-            }
-            Addr::Float(n) => {
-                Ok(Number::Float(n))
-            }
             Addr::Usize(n) => {
                 if let Ok(n) = isize::try_from(n) {
                     Ok(Number::from(n))
@@ -740,12 +708,8 @@ impl<'a> TryFrom<(Addr, &'a Heap)> for Number {
                     Ok(Number::from(Integer::from(n)))
                 }
             }
-            Addr::Con(h) => {
+            Addr::Con(h) => Number::try_from(&heap[h]),
-                Number::try_from(&heap[h])
+            _ => Err(()),
-            }
-            _ => {
-                Err(())
-            }
         }
     }
 }
@@ -755,35 +719,21 @@ impl<'a> TryFrom<&'a HeapCellValue> for Number {
 
     fn try_from(value: &'a HeapCellValue) -> Result<Number, Self::Error> {
         match value {
-            HeapCellValue::Addr(addr) => {
+            HeapCellValue::Addr(addr) => match addr {
-                match addr {
+                &Addr::Fixnum(n) => Ok(Number::from(n)),
-                    &Addr::Fixnum(n) => {
+                &Addr::Float(n) => Ok(Number::Float(n)),
+                &Addr::Usize(n) => {
+                    if let Ok(n) = isize::try_from(n) {
                         Ok(Number::from(n))
-                    }
+                    } else {
-                    &Addr::Float(n) => {
+                        Ok(Number::from(Integer::from(n)))
-                        Ok(Number::Float(n))
-                    }
-                    &Addr::Usize(n) => {
-                        if let Ok(n) = isize::try_from(n) {
-                            Ok(Number::from(n))
-                        } else {
-                            Ok(Number::from(Integer::from(n)))
-                        }
-                    }
-                    _ => {
-                        Err(())
                     }
                 }
-            }
+                _ => Err(()),
-            HeapCellValue::Integer(n) => {
+            },
-                Ok(Number::Integer(n.clone()))
+            HeapCellValue::Integer(n) => Ok(Number::Integer(n.clone())),
-            }
+            HeapCellValue::Rational(n) => Ok(Number::Rational(n.clone())),
-            HeapCellValue::Rational(n) => {
+            _ => Err(()),
-                Ok(Number::Rational(n.clone()))
-            }
-            _ => {
-                Err(())
-            }
         }
     }
 }

src/clause_types.rs

@@ -1,10 +1,11 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::{clause_name, temp_v};
 
 use crate::forms::Number;
 use crate::machine::machine_indices::*;
 use crate::rug::rand::RandState;
 
-use crate::ref_thread_local::RefThreadLocal;
+use crate::ref_thread_local::{ref_thread_local, RefThreadLocal};
 
 use std::collections::BTreeMap;
 
@@ -322,7 +323,9 @@ impl SystemClauseType {
             &SystemClauseType::ClearAttributeGoals => clause_name!("$clear_attribute_goals"),
             &SystemClauseType::CloneAttributeGoals => clause_name!("$clone_attribute_goals"),
             &SystemClauseType::CodesToNumber => clause_name!("$codes_to_number"),
-            &SystemClauseType::CopyTermWithoutAttrVars => clause_name!("$copy_term_without_attr_vars"),
+            &SystemClauseType::CopyTermWithoutAttrVars => {
+                clause_name!("$copy_term_without_attr_vars")
+            }
             &SystemClauseType::CreatePartialString => clause_name!("$create_partial_string"),
             &SystemClauseType::CurrentInput => clause_name!("$current_input"),
             &SystemClauseType::CurrentHostname => clause_name!("$current_hostname"),
@@ -337,58 +340,70 @@ impl SystemClauseType {
             &SystemClauseType::WorkingDirectory => clause_name!("$working_directory"),
             &SystemClauseType::PathCanonical => clause_name!("$path_canonical"),
             &SystemClauseType::FileTime => clause_name!("$file_time"),
-            &SystemClauseType::REPL(REPLCodePtr::AddDynamicPredicate) =>
+            &SystemClauseType::REPL(REPLCodePtr::AddDynamicPredicate) => {
-                clause_name!("$add_dynamic_predicate"),
+                clause_name!("$add_dynamic_predicate")
-            &SystemClauseType::REPL(REPLCodePtr::AddGoalExpansionClause) =>
+            }
-                clause_name!("$add_goal_expansion_clause"),
+            &SystemClauseType::REPL(REPLCodePtr::AddGoalExpansionClause) => {
-            &SystemClauseType::REPL(REPLCodePtr::AddTermExpansionClause) =>
+                clause_name!("$add_goal_expansion_clause")
-                clause_name!("$add_term_expansion_clause"),
+            }
-            &SystemClauseType::REPL(REPLCodePtr::ClauseToEvacuable) =>
+            &SystemClauseType::REPL(REPLCodePtr::AddTermExpansionClause) => {
-                clause_name!("$clause_to_evacuable"),
+                clause_name!("$add_term_expansion_clause")
-            &SystemClauseType::REPL(REPLCodePtr::ConcludeLoad) =>
+            }
-                clause_name!("$conclude_load"),
+            &SystemClauseType::REPL(REPLCodePtr::ClauseToEvacuable) => {
-            &SystemClauseType::REPL(REPLCodePtr::DeclareModule) =>
+                clause_name!("$clause_to_evacuable")
-                clause_name!("$declare_module"),
+            }
-            &SystemClauseType::REPL(REPLCodePtr::LoadCompiledLibrary) =>
+            &SystemClauseType::REPL(REPLCodePtr::ConcludeLoad) => clause_name!("$conclude_load"),
-                clause_name!("$load_compiled_library"),
+            &SystemClauseType::REPL(REPLCodePtr::DeclareModule) => clause_name!("$declare_module"),
-            &SystemClauseType::REPL(REPLCodePtr::PushLoadStatePayload) =>
+            &SystemClauseType::REPL(REPLCodePtr::LoadCompiledLibrary) => {
-                clause_name!("$push_load_state_payload"),
+                clause_name!("$load_compiled_library")
-            &SystemClauseType::REPL(REPLCodePtr::Asserta) =>
+            }
-                clause_name!("$asserta"),
+            &SystemClauseType::REPL(REPLCodePtr::PushLoadStatePayload) => {
-            &SystemClauseType::REPL(REPLCodePtr::Assertz) =>
+                clause_name!("$push_load_state_payload")
-                clause_name!("$assertz"),
+            }
-            &SystemClauseType::REPL(REPLCodePtr::Retract) =>
+            &SystemClauseType::REPL(REPLCodePtr::Asserta) => clause_name!("$asserta"),
-                clause_name!("$retract_clause"),
+            &SystemClauseType::REPL(REPLCodePtr::Assertz) => clause_name!("$assertz"),
-            &SystemClauseType::REPL(REPLCodePtr::UseModule) =>
+            &SystemClauseType::REPL(REPLCodePtr::Retract) => clause_name!("$retract_clause"),
-                clause_name!("$use_module"),
+            &SystemClauseType::REPL(REPLCodePtr::UseModule) => clause_name!("$use_module"),
-            &SystemClauseType::REPL(REPLCodePtr::PushLoadContext) =>
+            &SystemClauseType::REPL(REPLCodePtr::PushLoadContext) => {
-                clause_name!("$push_load_context"),
+                clause_name!("$push_load_context")
-            &SystemClauseType::REPL(REPLCodePtr::PopLoadContext) =>
+            }
-                clause_name!("$pop_load_context"),
+            &SystemClauseType::REPL(REPLCodePtr::PopLoadContext) => {
-            &SystemClauseType::REPL(REPLCodePtr::PopLoadStatePayload) =>
+                clause_name!("$pop_load_context")
-                clause_name!("$pop_load_state_payload"),
+            }
-            &SystemClauseType::REPL(REPLCodePtr::LoadContextSource) =>
+            &SystemClauseType::REPL(REPLCodePtr::PopLoadStatePayload) => {
-                clause_name!("$prolog_lc_source"),
+                clause_name!("$pop_load_state_payload")
-            &SystemClauseType::REPL(REPLCodePtr::LoadContextFile) =>
+            }
-                clause_name!("$prolog_lc_file"),
+            &SystemClauseType::REPL(REPLCodePtr::LoadContextSource) => {
-            &SystemClauseType::REPL(REPLCodePtr::LoadContextDirectory) =>
+                clause_name!("$prolog_lc_source")
-                clause_name!("$prolog_lc_dir"),
+            }
-            &SystemClauseType::REPL(REPLCodePtr::LoadContextModule) =>
+            &SystemClauseType::REPL(REPLCodePtr::LoadContextFile) => {
-                clause_name!("$prolog_lc_module"),
+                clause_name!("$prolog_lc_file")
-            &SystemClauseType::REPL(REPLCodePtr::LoadContextStream) =>
+            }
-                clause_name!("$prolog_lc_stream"),
+            &SystemClauseType::REPL(REPLCodePtr::LoadContextDirectory) => {
-            &SystemClauseType::REPL(REPLCodePtr::MetaPredicateProperty) =>
+                clause_name!("$prolog_lc_dir")
-                clause_name!("$cpp_meta_predicate_property"),
+            }
-            &SystemClauseType::REPL(REPLCodePtr::BuiltInProperty) =>
+            &SystemClauseType::REPL(REPLCodePtr::LoadContextModule) => {
-                clause_name!("$cpp_built_in_property"),
+                clause_name!("$prolog_lc_module")
-            &SystemClauseType::REPL(REPLCodePtr::DynamicProperty) =>
+            }
-                clause_name!("$cpp_dynamic_property"),
+            &SystemClauseType::REPL(REPLCodePtr::LoadContextStream) => {
-            &SystemClauseType::REPL(REPLCodePtr::MultifileProperty) =>
+                clause_name!("$prolog_lc_stream")
-                clause_name!("$cpp_multifile_property"),
+            }
-            &SystemClauseType::REPL(REPLCodePtr::DiscontiguousProperty) =>
+            &SystemClauseType::REPL(REPLCodePtr::MetaPredicateProperty) => {
-                clause_name!("$cpp_discontiguous_property"),
+                clause_name!("$cpp_meta_predicate_property")
-            &SystemClauseType::REPL(REPLCodePtr::AbolishClause) =>
+            }
-                clause_name!("$abolish_clause"),
+            &SystemClauseType::REPL(REPLCodePtr::BuiltInProperty) => {
+                clause_name!("$cpp_built_in_property")
+            }
+            &SystemClauseType::REPL(REPLCodePtr::DynamicProperty) => {
+                clause_name!("$cpp_dynamic_property")
+            }
+            &SystemClauseType::REPL(REPLCodePtr::MultifileProperty) => {
+                clause_name!("$cpp_multifile_property")
+            }
+            &SystemClauseType::REPL(REPLCodePtr::DiscontiguousProperty) => {
+                clause_name!("$cpp_discontiguous_property")
+            }
+            &SystemClauseType::REPL(REPLCodePtr::AbolishClause) => clause_name!("$abolish_clause"),
             &SystemClauseType::Close => clause_name!("$close"),
             &SystemClauseType::CopyToLiftedHeap => clause_name!("$copy_to_lh"),
             &SystemClauseType::DeleteAttribute => clause_name!("$del_attr_non_head"),
@@ -397,8 +412,9 @@ impl SystemClauseType {
             &SystemClauseType::EnqueueAttributeGoal => clause_name!("$enqueue_attribute_goal"),
             &SystemClauseType::EnqueueAttributedVar => clause_name!("$enqueue_attr_var"),
             &SystemClauseType::FetchGlobalVar => clause_name!("$fetch_global_var"),
-            &SystemClauseType::FetchGlobalVarWithOffset =>
+            &SystemClauseType::FetchGlobalVarWithOffset => {
-                clause_name!("$fetch_global_var_with_offset"),
+                clause_name!("$fetch_global_var_with_offset")
+            }
             &SystemClauseType::FirstStream => clause_name!("$first_stream"),
             &SystemClauseType::FlushOutput => clause_name!("$flush_output"),
             &SystemClauseType::GetByte => clause_name!("$get_byte"),
@@ -424,13 +440,13 @@ impl SystemClauseType {
                 clause_name!("$get_lh_from_offset_diff")
             }
             &SystemClauseType::GetBValue => clause_name!("$get_b_value"),
-//          &SystemClauseType::GetClause => clause_name!("$get_clause"),
+            //          &SystemClauseType::GetClause => clause_name!("$get_clause"),
             &SystemClauseType::GetNextDBRef => clause_name!("$get_next_db_ref"),
             &SystemClauseType::GetNextOpDBRef => clause_name!("$get_next_op_db_ref"),
             &SystemClauseType::LookupDBRef => clause_name!("$lookup_db_ref"),
             &SystemClauseType::LookupOpDBRef => clause_name!("$lookup_op_db_ref"),
             &SystemClauseType::GetDoubleQuotes => clause_name!("$get_double_quotes"),
-//          &SystemClauseType::GetModuleClause => clause_name!("$get_module_clause"),
+            //          &SystemClauseType::GetModuleClause => clause_name!("$get_module_clause"),
             &SystemClauseType::GetSCCCleaner => clause_name!("$get_scc_cleaner"),
             &SystemClauseType::Halt => clause_name!("$halt"),
             &SystemClauseType::HeadIsDynamic => clause_name!("$head_is_dynamic"),
@@ -455,7 +471,7 @@ impl SystemClauseType {
             // &SystemClauseType::ModuleAssertDynamicPredicateToBack => {
             //     clause_name!("$module_assertz")
             // }
-//          &SystemClauseType::ModuleHeadIsDynamic => clause_name!("$module_head_is_dynamic"),
+            //          &SystemClauseType::ModuleHeadIsDynamic => clause_name!("$module_head_is_dynamic"),
             &SystemClauseType::ModuleExists => clause_name!("$module_exists"),
             &SystemClauseType::NextStream => clause_name!("$next_stream"),
             &SystemClauseType::NoSuchPredicate => clause_name!("$no_such_predicate"),
@@ -507,7 +523,9 @@ impl SystemClauseType {
             &SystemClauseType::ReadTerm => clause_name!("$read_term"),
             &SystemClauseType::ReadTermFromChars => clause_name!("$read_term_from_chars"),
             &SystemClauseType::ResetGlobalVarAtKey => clause_name!("$reset_global_var_at_key"),
-            &SystemClauseType::ResetGlobalVarAtOffset => clause_name!("$reset_global_var_at_offset"),
+            &SystemClauseType::ResetGlobalVarAtOffset => {
+                clause_name!("$reset_global_var_at_offset")
+            }
             &SystemClauseType::ResetBlock => clause_name!("$reset_block"),
             &SystemClauseType::ResetContinuationMarker => clause_name!("$reset_cont_marker"),
             &SystemClauseType::ReturnFromVerifyAttr => clause_name!("$return_from_verify_attr"),
@@ -521,7 +539,9 @@ impl SystemClauseType {
             &SystemClauseType::SocketServerAccept => clause_name!("$socket_server_accept"),
             &SystemClauseType::SocketServerClose => clause_name!("$socket_server_close"),
             &SystemClauseType::Succeed => clause_name!("$succeed"),
-            &SystemClauseType::TermAttributedVariables => clause_name!("$term_attributed_variables"),
+            &SystemClauseType::TermAttributedVariables => {
+                clause_name!("$term_attributed_variables")
+            }
             &SystemClauseType::TermVariables => clause_name!("$term_variables"),
             &SystemClauseType::TruncateLiftedHeapTo => clause_name!("$truncate_lh_to"),
             &SystemClauseType::UnifyWithOccursCheck => clause_name!("$unify_with_occurs_check"),
@@ -542,7 +562,9 @@ impl SystemClauseType {
             &SystemClauseType::Ed25519Sign => clause_name!("$ed25519_sign"),
             &SystemClauseType::Ed25519Verify => clause_name!("$ed25519_verify"),
             &SystemClauseType::Ed25519NewKeyPair => clause_name!("$ed25519_new_keypair"),
-            &SystemClauseType::Ed25519KeyPairPublicKey => clause_name!("$ed25519_keypair_public_key"),
+            &SystemClauseType::Ed25519KeyPairPublicKey => {
+                clause_name!("$ed25519_keypair_public_key")
+            }
             &SystemClauseType::Curve25519ScalarMult => clause_name!("$curve25519_scalar_mult"),
             &SystemClauseType::LoadHTML => clause_name!("$load_html"),
             &SystemClauseType::LoadXML => clause_name!("$load_xml"),
@@ -556,14 +578,16 @@ impl SystemClauseType {
 
     pub fn from(name: &str, arity: usize) -> Option<SystemClauseType> {
         match (name, arity) {
-            ("$abolish_clause", 3) =>
+            ("$abolish_clause", 3) => Some(SystemClauseType::REPL(REPLCodePtr::AbolishClause)),
-                Some(SystemClauseType::REPL(REPLCodePtr::AbolishClause)),
+            ("$add_dynamic_predicate", 3) => {
-            ("$add_dynamic_predicate", 3) =>
+                Some(SystemClauseType::REPL(REPLCodePtr::AddDynamicPredicate))
-                Some(SystemClauseType::REPL(REPLCodePtr::AddDynamicPredicate)),
+            }
-            ("$add_goal_expansion_clause", 4) =>
+            ("$add_goal_expansion_clause", 4) => {
-                Some(SystemClauseType::REPL(REPLCodePtr::AddGoalExpansionClause)),
+                Some(SystemClauseType::REPL(REPLCodePtr::AddGoalExpansionClause))
-            ("$add_term_expansion_clause", 3) =>
+            }
-                Some(SystemClauseType::REPL(REPLCodePtr::AddTermExpansionClause)),
+            ("$add_term_expansion_clause", 3) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::AddTermExpansionClause))
+            }
             ("$atom_chars", 2) => Some(SystemClauseType::AtomChars),
             ("$atom_codes", 2) => Some(SystemClauseType::AtomCodes),
             ("$atom_length", 2) => Some(SystemClauseType::AtomLength),
@@ -602,7 +626,9 @@ impl SystemClauseType {
             ("$peek_code", 2) => Some(SystemClauseType::PeekCode),
             ("$is_partial_string", 1) => Some(SystemClauseType::IsPartialString),
             ("$fetch_global_var", 2) => Some(SystemClauseType::FetchGlobalVar),
-            ("$fetch_global_var_with_offset", 3) => Some(SystemClauseType::FetchGlobalVarWithOffset),
+            ("$fetch_global_var_with_offset", 3) => {
+                Some(SystemClauseType::FetchGlobalVarWithOffset)
+            }
             ("$get_byte", 2) => Some(SystemClauseType::GetByte),
             ("$get_char", 2) => Some(SystemClauseType::GetChar),
             ("$get_n_chars", 3) => Some(SystemClauseType::GetNChars),
@@ -611,18 +637,10 @@ impl SystemClauseType {
             ("$points_to_cont_reset_marker", 1) => {
                 Some(SystemClauseType::PointsToContinuationResetMarker)
             }
-            ("$put_byte", 2) => {
+            ("$put_byte", 2) => Some(SystemClauseType::PutByte),
-                Some(SystemClauseType::PutByte)
+            ("$put_char", 2) => Some(SystemClauseType::PutChar),
-            }
+            ("$put_chars", 2) => Some(SystemClauseType::PutChars),
-            ("$put_char", 2) => {
+            ("$put_code", 2) => Some(SystemClauseType::PutCode),
-                Some(SystemClauseType::PutChar)
-            }
-            ("$put_chars", 2) => {
-                Some(SystemClauseType::PutChars)
-            }
-            ("$put_code", 2) => {
-                Some(SystemClauseType::PutCode)
-            }
             ("$reset_attr_var_state", 0) => Some(SystemClauseType::ResetAttrVarState),
             ("$truncate_if_no_lh_growth", 1) => {
                 Some(SystemClauseType::TruncateIfNoLiftedHeapGrowth)
@@ -691,7 +709,9 @@ impl SystemClauseType {
             ("$socket_server_accept", 7) => Some(SystemClauseType::SocketServerAccept),
             ("$socket_server_close", 1) => Some(SystemClauseType::SocketServerClose),
             ("$store_global_var", 2) => Some(SystemClauseType::StoreGlobalVar),
-            ("$store_global_var_with_offset", 2) => Some(SystemClauseType::StoreGlobalVarWithOffset),
+            ("$store_global_var_with_offset", 2) => {
+                Some(SystemClauseType::StoreGlobalVarWithOffset)
+            }
             ("$term_attributed_variables", 2) => Some(SystemClauseType::TermAttributedVariables),
             ("$term_variables", 2) => Some(SystemClauseType::TermVariables),
             ("$truncate_lh_to", 1) => Some(SystemClauseType::TruncateLiftedHeapTo),
@@ -708,12 +728,18 @@ impl SystemClauseType {
             ("$working_directory", 2) => Some(SystemClauseType::WorkingDirectory),
             ("$path_canonical", 2) => Some(SystemClauseType::PathCanonical),
             ("$file_time", 3) => Some(SystemClauseType::FileTime),
-            ("$clause_to_evacuable", 3) => Some(SystemClauseType::REPL(REPLCodePtr::ClauseToEvacuable)),
+            ("$clause_to_evacuable", 3) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::ClauseToEvacuable))
+            }
             ("$conclude_load", 1) => Some(SystemClauseType::REPL(REPLCodePtr::ConcludeLoad)),
             ("$use_module", 3) => Some(SystemClauseType::REPL(REPLCodePtr::UseModule)),
             ("$declare_module", 3) => Some(SystemClauseType::REPL(REPLCodePtr::DeclareModule)),
-            ("$load_compiled_library", 2) => Some(SystemClauseType::REPL(REPLCodePtr::LoadCompiledLibrary)),
+            ("$load_compiled_library", 2) => {
-            ("$push_load_state_payload", 1) => Some(SystemClauseType::REPL(REPLCodePtr::PushLoadStatePayload)),
+                Some(SystemClauseType::REPL(REPLCodePtr::LoadCompiledLibrary))
+            }
+            ("$push_load_state_payload", 1) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::PushLoadStatePayload))
+            }
             ("$asserta", 5) => Some(SystemClauseType::REPL(REPLCodePtr::Asserta)),
             ("$assertz", 5) => Some(SystemClauseType::REPL(REPLCodePtr::Assertz)),
             ("$retract_clause", 4) => Some(SystemClauseType::REPL(REPLCodePtr::Retract)),
@@ -742,18 +768,38 @@ impl SystemClauseType {
             ("$chars_base64", 4) => Some(SystemClauseType::CharsBase64),
             ("$load_library_as_stream", 3) => Some(SystemClauseType::LoadLibraryAsStream),
             ("$push_load_context", 2) => Some(SystemClauseType::REPL(REPLCodePtr::PushLoadContext)),
-            ("$pop_load_state_payload", 1) => Some(SystemClauseType::REPL(REPLCodePtr::PopLoadStatePayload)),
+            ("$pop_load_state_payload", 1) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::PopLoadStatePayload))
+            }
             ("$pop_load_context", 0) => Some(SystemClauseType::REPL(REPLCodePtr::PopLoadContext)),
-            ("$prolog_lc_source", 1) => Some(SystemClauseType::REPL(REPLCodePtr::LoadContextSource)),
+            ("$prolog_lc_source", 1) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::LoadContextSource))
+            }
             ("$prolog_lc_file", 1) => Some(SystemClauseType::REPL(REPLCodePtr::LoadContextFile)),
-            ("$prolog_lc_dir", 1) => Some(SystemClauseType::REPL(REPLCodePtr::LoadContextDirectory)),
+            ("$prolog_lc_dir", 1) => {
-            ("$prolog_lc_module", 1) => Some(SystemClauseType::REPL(REPLCodePtr::LoadContextModule)),
+                Some(SystemClauseType::REPL(REPLCodePtr::LoadContextDirectory))
-            ("$prolog_lc_stream", 1) => Some(SystemClauseType::REPL(REPLCodePtr::LoadContextStream)),
+            }
-            ("$cpp_meta_predicate_property", 4) => Some(SystemClauseType::REPL(REPLCodePtr::MetaPredicateProperty)),
+            ("$prolog_lc_module", 1) => {
-            ("$cpp_built_in_property", 2) => Some(SystemClauseType::REPL(REPLCodePtr::BuiltInProperty)),
+                Some(SystemClauseType::REPL(REPLCodePtr::LoadContextModule))
-            ("$cpp_dynamic_property", 3) => Some(SystemClauseType::REPL(REPLCodePtr::DynamicProperty)),
+            }
-            ("$cpp_multifile_property", 3) => Some(SystemClauseType::REPL(REPLCodePtr::MultifileProperty)),
+            ("$prolog_lc_stream", 1) => {
-            ("$cpp_discontiguous_property", 3) => Some(SystemClauseType::REPL(REPLCodePtr::DiscontiguousProperty)),
+                Some(SystemClauseType::REPL(REPLCodePtr::LoadContextStream))
+            }
+            ("$cpp_meta_predicate_property", 4) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::MetaPredicateProperty))
+            }
+            ("$cpp_built_in_property", 2) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::BuiltInProperty))
+            }
+            ("$cpp_dynamic_property", 3) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::DynamicProperty))
+            }
+            ("$cpp_multifile_property", 3) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::MultifileProperty))
+            }
+            ("$cpp_discontiguous_property", 3) => {
+                Some(SystemClauseType::REPL(REPLCodePtr::DiscontiguousProperty))
+            }
             _ => None,
         }
     }
@@ -832,10 +878,10 @@ impl ClauseType {
         match self {
             &ClauseType::Op(_, ref spec, _) => Some(spec.clone()),
             &ClauseType::Inlined(InlinedClauseType::CompareNumber(..))
-          | &ClauseType::BuiltIn(BuiltInClauseType::Is(..))
+            | &ClauseType::BuiltIn(BuiltInClauseType::Is(..))
-          | &ClauseType::BuiltIn(BuiltInClauseType::CompareTerm(_))
+            | &ClauseType::BuiltIn(BuiltInClauseType::CompareTerm(_))
-          | &ClauseType::BuiltIn(BuiltInClauseType::NotEq)
+            | &ClauseType::BuiltIn(BuiltInClauseType::NotEq)
-          | &ClauseType::BuiltIn(BuiltInClauseType::Eq) => Some(SharedOpDesc::new(700, XFX)),
+            | &ClauseType::BuiltIn(BuiltInClauseType::Eq) => Some(SharedOpDesc::new(700, XFX)),
             _ => None,
         }
     }

src/codegen.rs

@@ -1,6 +1,7 @@
 /// Code generation to WAM-like instructions.
 use crate::prolog_parser_rebis::ast::*;
 use crate::prolog_parser_rebis::tabled_rc::TabledData;
+use crate::prolog_parser_rebis::{perm_v, temp_v};
 
 use crate::allocator::*;
 use crate::arithmetic::*;
@@ -66,18 +67,14 @@ impl<'a> ConjunctInfo<'a> {
         self.has_deep_cut as usize
     }
 
-    fn mark_unsafe_vars(
+    fn mark_unsafe_vars(&self, mut unsafe_var_marker: UnsafeVarMarker, code: &mut Code) {
-        &self,
-        mut unsafe_var_marker: UnsafeVarMarker,
-        code: &mut Code,
-    ) {
         if code.is_empty() {
             return;
         }
 
         let mut code_index = 0;
 
-        for phase in 0 .. {
+        for phase in 0.. {
             while let Line::Query(ref query_instr) = &code[code_index] {
                 if !unsafe_var_marker.mark_safe_vars(query_instr) {
                     unsafe_var_marker.mark_phase(query_instr, phase);
@@ -95,7 +92,7 @@ impl<'a> ConjunctInfo<'a> {
 
         code_index = 0;
 
-        for phase in 0 .. {
+        for phase in 0.. {
             while let Line::Query(ref mut query_instr) = &mut code[code_index] {
                 unsafe_var_marker.mark_unsafe_vars(query_instr, phase);
                 code_index += 1;
@@ -173,7 +170,8 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         code: &mut Code,
     ) -> RegType {
         let mut target = Vec::new();
-        self.marker.mark_var(name, Level::Shallow, vr, term_loc, &mut target);
+        self.marker
+            .mark_var(name, Level::Shallow, vr, term_loc, &mut target);
 
         if !target.is_empty() {
             code.extend(target.into_iter().map(Line::Query));
@@ -191,9 +189,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         code: &mut Code,
     ) -> RegType {
         match self.marker.bindings().get(&name) {
-            Some(&VarData::Temp(_, t, _)) if t != 0 => {
+            Some(&VarData::Temp(_, t, _)) if t != 0 => RegType::Temp(t),
-                RegType::Temp(t)
-            }
             Some(&VarData::Perm(p)) if p != 0 => {
                 if let GenContext::Last(_) = term_loc {
                     self.mark_var_in_non_callable(name.clone(), term_loc, vr, code);
@@ -202,9 +198,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                     RegType::Perm(p)
                 }
             }
-            _ => {
+            _ => self.mark_var_in_non_callable(name, term_loc, vr, code),
-                self.mark_var_in_non_callable(name, term_loc, vr, code)
-            }
         }
     }
 
@@ -231,7 +225,8 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         target: &mut Vec<Target>,
     ) {
         if is_exposed || self.get_var_count(var.as_ref()) > 1 {
-            self.marker.mark_var(var.clone(), Level::Deep, cell, term_loc, target);
+            self.marker
+                .mark_var(var.clone(), Level::Deep, cell, term_loc, target);
         } else {
             Self::add_or_increment_void_instr(target);
         }
@@ -252,7 +247,8 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                 Self::add_or_increment_void_instr(target);
             }
             &Term::Cons(ref cell, _, _) | &Term::Clause(ref cell, _, _, _) => {
-                self.marker.mark_non_var(Level::Deep, term_loc, cell, target);
+                self.marker
+                    .mark_non_var(Level::Deep, term_loc, cell, target);
                 target.push(Target::clause_arg_to_instr(cell.get()));
             }
             &Term::Constant(_, ref constant) => {
@@ -264,7 +260,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         };
     }
 
-     fn compile_target<Target, Iter>(
+    fn compile_target<Target, Iter>(
         &mut self,
         iter: Iter,
         term_loc: GenContext,
@@ -334,13 +330,14 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                         }
                     }
 
-                    self.marker.mark_var(var.clone(), lvl, cell, term_loc, &mut target);
+                    self.marker
+                        .mark_var(var.clone(), lvl, cell, term_loc, &mut target);
                 }
                 TermRef::Var(lvl @ Level::Shallow, cell, var) => {
-                    self.marker.mark_var(var.clone(), lvl, cell, term_loc, &mut target);
+                    self.marker
-                }
+                        .mark_var(var.clone(), lvl, cell, term_loc, &mut target);
-                _ => {
                 }
+                _ => {}
             };
         }
 
@@ -353,8 +350,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         while let Some((chunk_num, lt_arity, chunked_terms)) = iter.next() {
             for (i, chunked_term) in chunked_terms.iter().enumerate() {
                 let term_loc = match chunked_term {
-                    &ChunkedTerm::HeadClause(..) =>
+                    &ChunkedTerm::HeadClause(..) => GenContext::Head,
-                        GenContext::Head,
                     &ChunkedTerm::BodyTerm(_) => {
                         if i < chunked_terms.len() - 1 {
                             GenContext::Mid(chunk_num)
@@ -391,8 +387,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
             &QueryTerm::Clause(_, ref ct, ref terms, false) => {
                 code.push(call_clause!(ct.clone(), terms.len(), pvs));
             }
-            _ => {
+            _ => {}
-            }
         }
     }
 
@@ -407,8 +402,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                 &mut ControlInstruction::JmpBy(_, _, _, ref mut last_call) => {
                     *last_call = true;
                 }
-                &mut ControlInstruction::Proceed => {
+                &mut ControlInstruction::Proceed => {}
-                }
                 _ => {
                     dealloc_index += 1;
                 }
@@ -416,8 +410,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
             Some(&mut Line::Cut(CutInstruction::Cut(_))) => {
                 dealloc_index += 1;
             }
-            _ => {
+            _ => {}
-            }
         };
 
         dealloc_index
@@ -437,23 +430,17 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                 let (mut lcode, at_1) = self.call_arith_eval(terms[0].as_ref(), 1)?;
                 let (mut rcode, at_2) = self.call_arith_eval(terms[1].as_ref(), 2)?;
 
-                let at_1 =
+                let at_1 = if let &Term::Var(ref vr, ref name) = terms[0].as_ref() {
-                    if let &Term::Var(ref vr, ref name) = terms[0].as_ref() {
+                    ArithmeticTerm::Reg(self.mark_non_callable(name.clone(), 1, term_loc, vr, code))
-                        ArithmeticTerm::Reg(
+                } else {
-                            self.mark_non_callable(name.clone(), 1, term_loc, vr, code)
+                    at_1.unwrap_or(interm!(1))
-                        )
+                };
-                    } else {
-                        at_1.unwrap_or(interm!(1))
-                    };
 
-                let at_2 =
+                let at_2 = if let &Term::Var(ref vr, ref name) = terms[1].as_ref() {
-                    if let &Term::Var(ref vr, ref name) = terms[1].as_ref() {
+                    ArithmeticTerm::Reg(self.mark_non_callable(name.clone(), 2, term_loc, vr, code))
-                        ArithmeticTerm::Reg(
+                } else {
-                            self.mark_non_callable(name.clone(), 2, term_loc, vr, code)
+                    at_2.unwrap_or(interm!(2))
-                        )
+                };
-                    } else {
-                        at_2.unwrap_or(interm!(2))
-                    };
 
                 code.append(&mut lcode);
                 code.append(&mut rcode);
@@ -461,9 +448,9 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                 code.push(compare_number_instr!(cmp, at_1, at_2));
             }
             &InlinedClauseType::IsAtom(..) => match terms[0].as_ref() {
-                &Term::Constant(_, Constant::Char(_)) |
+                &Term::Constant(_, Constant::Char(_))
-                &Term::Constant(_, Constant::EmptyList) |
+                | &Term::Constant(_, Constant::EmptyList)
-                &Term::Constant(_, Constant::Atom(..)) => {
+                | &Term::Constant(_, Constant::Atom(..)) => {
                     code.push(succeed!());
                 }
                 &Term::Var(ref vr, ref name) => {
@@ -528,11 +515,11 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                 }
             },
             &InlinedClauseType::IsNumber(..) => match terms[0].as_ref() {
-                &Term::Constant(_, Constant::Float(_)) |
+                &Term::Constant(_, Constant::Float(_))
-                &Term::Constant(_, Constant::Rational(_)) |
+                | &Term::Constant(_, Constant::Rational(_))
-                &Term::Constant(_, Constant::Integer(_)) |
+                | &Term::Constant(_, Constant::Integer(_))
-                &Term::Constant(_, Constant::Fixnum(_)) |
+                | &Term::Constant(_, Constant::Fixnum(_))
-                &Term::Constant(_, Constant::Usize(_)) => {
+                | &Term::Constant(_, Constant::Usize(_)) => {
                     code.push(succeed!());
                 }
                 &Term::Var(ref vr, ref name) => {
@@ -558,9 +545,9 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                 }
             },
             &InlinedClauseType::IsInteger(..) => match terms[0].as_ref() {
-                &Term::Constant(_, Constant::Integer(_)) |
+                &Term::Constant(_, Constant::Integer(_))
-                &Term::Constant(_, Constant::Fixnum(_)) |
+                | &Term::Constant(_, Constant::Fixnum(_))
-                &Term::Constant(_, Constant::Usize(_)) => {
+                | &Term::Constant(_, Constant::Usize(_)) => {
                     code.push(succeed!());
                 }
                 &Term::Var(ref vr, ref name) => {
@@ -615,14 +602,15 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
             &Term::Var(ref vr, ref name) => {
                 let mut target = vec![];
 
-                self.marker.mark_var(name.clone(), Level::Shallow, vr, term_loc, &mut target);
+                self.marker
+                    .mark_var(name.clone(), Level::Shallow, vr, term_loc, &mut target);
 
                 if !target.is_empty() {
                     code.extend(target.into_iter().map(Line::Query));
                 }
             }
-            &Term::Constant(_, ref c @ Constant::Integer(_)) |
+            &Term::Constant(_, ref c @ Constant::Integer(_))
-            &Term::Constant(_, ref c @ Constant::Fixnum(_)) => {
+            | &Term::Constant(_, ref c @ Constant::Fixnum(_)) => {
                 code.push(Line::Query(put_constant!(
                     Level::Shallow,
                     c.clone(),
@@ -655,14 +643,11 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
             }
         }
 
-        let at =
+        let at = if let &Term::Var(ref vr, ref name) = terms[1].as_ref() {
-            if let &Term::Var(ref vr, ref name) = terms[1].as_ref() {
+            ArithmeticTerm::Reg(self.mark_non_callable(name.clone(), 2, term_loc, vr, code))
-                ArithmeticTerm::Reg(
+        } else {
-                    self.mark_non_callable(name.clone(), 2, term_loc, vr, code)
+            at.unwrap_or(interm!(1))
-                )
+        };
-            } else {
-                at.unwrap_or(interm!(1))
-            };
 
         Ok(if use_default_call_policy {
             code.push(is_call_by_default!(temp_v!(1), at));
@@ -721,24 +706,18 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
                     &QueryTerm::GetLevelAndUnify(ref cell, ref var) => {
                         self.compile_get_level_and_unify(code, cell, var.clone(), term_loc)
                     }
-                    &QueryTerm::UnblockedCut(ref cell) => {
+                    &QueryTerm::UnblockedCut(ref cell) => self.compile_unblocked_cut(code, cell),
-                        self.compile_unblocked_cut(code, cell)
+                    &QueryTerm::BlockedCut => code.push(if chunk_num == 0 {
-                    }
+                        Line::Cut(CutInstruction::NeckCut)
-                    &QueryTerm::BlockedCut => {
+                    } else {
-                        code.push(if chunk_num == 0 {
+                        Line::Cut(CutInstruction::Cut(perm_v!(1)))
-                            Line::Cut(CutInstruction::NeckCut)
+                    }),
-                        } else {
-                            Line::Cut(CutInstruction::Cut(perm_v!(1)))
-                        })
-                    }
                     &QueryTerm::Clause(
                         _,
                         ClauseType::BuiltIn(BuiltInClauseType::Is(..)),
                         ref terms,
                         use_default_call_policy,
-                    ) => {
+                    ) => self.compile_is_call(terms, code, term_loc, use_default_call_policy)?,
-                        self.compile_is_call(terms, code, term_loc, use_default_call_policy)?
-                    }
                     &QueryTerm::Clause(_, ClauseType::Inlined(ref ct), ref terms, _) => {
                         self.compile_inlined(ct, terms, term_loc, code)?
                     }
@@ -772,7 +751,12 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         }
     }
 
-    fn compile_cleanup(&mut self, code: &mut Code, conjunct_info: &ConjunctInfo, toc: &'a QueryTerm) {
+    fn compile_cleanup(
+        &mut self,
+        code: &mut Code,
+        conjunct_info: &ConjunctInfo,
+        toc: &'a QueryTerm,
+    ) {
         // add a proceed to bookend any trailing cuts.
         match toc {
             &QueryTerm::BlockedCut | &QueryTerm::UnblockedCut(..) => code.push(proceed!()),
@@ -786,7 +770,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         if conjunct_info.allocates() {
             let offset = self.global_jmp_by_locs_offset;
 
-            if let Some(jmp_by_offset) = self.jmp_by_locs[offset ..].last_mut() {
+            if let Some(jmp_by_offset) = self.jmp_by_locs[offset..].last_mut() {
                 if *jmp_by_offset == dealloc_index {
                     *jmp_by_offset += 1;
                 }
@@ -905,32 +889,32 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
         self.add_conditional_call(code, term, num_perm_vars_left);
     }
 
-/*
+    /*
-    pub fn compile_query(&mut self, query: &'a Vec<QueryTerm>) -> Result<Code, CompilationError> {
+        pub fn compile_query(&mut self, query: &'a Vec<QueryTerm>) -> Result<Code, CompilationError> {
-        let iter = ChunkedIterator::from_term_sequence(query);
+            let iter = ChunkedIterator::from_term_sequence(query);
-        let conjunct_info = self.collect_var_data(iter);
+            let conjunct_info = self.collect_var_data(iter);
 
-        let mut code = Vec::new();
+            let mut code = Vec::new();
-        self.compile_seq_prelude(&conjunct_info, &mut code);
+            self.compile_seq_prelude(&conjunct_info, &mut code);
 
-        let iter = ChunkedIterator::from_term_sequence(query);
+            let iter = ChunkedIterator::from_term_sequence(query);
-        self.compile_seq(iter, &conjunct_info, &mut code, true)?;
+            self.compile_seq(iter, &conjunct_info, &mut code, true)?;
 
-        conjunct_info.mark_unsafe_vars(UnsafeVarMarker::new(), &mut code);
+            conjunct_info.mark_unsafe_vars(UnsafeVarMarker::new(), &mut code);
 
-        if let Some(query_term) = query.last() {
+            if let Some(query_term) = query.last() {
-            Self::compile_cleanup(&mut code, &conjunct_info, query_term);
+                Self::compile_cleanup(&mut code, &conjunct_info, query_term);
+            }
+
+            Ok(code)
         }
-
+    */
-        Ok(code)
-    }
-*/
 
     #[inline]
     fn increment_jmp_by_locs_by(&mut self, incr: usize) {
         let offset = self.global_jmp_by_locs_offset;
 
-        for loc in &mut self.jmp_by_locs[offset ..] {
+        for loc in &mut self.jmp_by_locs[offset..] {
             *loc += incr;
         }
     }
@@ -1077,7 +1061,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
 
             if skip_stub_try_me_else {
                 // skip the TryMeElse(0) also.
-                 self.increment_jmp_by_locs_by(2);
+                self.increment_jmp_by_locs_by(2);
             } else {
                 self.increment_jmp_by_locs_by(1);
             }
@@ -1105,7 +1089,7 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
 
         for (l, r) in split_pred {
             let skel_lower_bound = self.skeleton.clauses.len();
-            let code_segment = self.compile_pred_subseq(&clauses[l .. r], optimal_index)?;
+            let code_segment = self.compile_pred_subseq(&clauses[l..r], optimal_index)?;
             let clause_start_offset = code.len();
 
             if multi_seq {
@@ -1123,11 +1107,10 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<TermMarker> {
             if self.is_extensible {
                 let segment_is_indexed = to_indexing_line(&code_segment[0]).is_some();
 
-                for clause_index_info in self.skeleton.clauses[skel_lower_bound ..].iter_mut() {
+                for clause_index_info in self.skeleton.clauses[skel_lower_bound..].iter_mut() {
                     clause_index_info.clause_start +=
                         clause_start_offset + 2 * (segment_is_indexed as usize);
-                    clause_index_info.opt_arg_index_key +=
+                    clause_index_info.opt_arg_index_key += clause_start_offset + 1;
-                        clause_start_offset + 1;
                 }
             }
 

src/debray_allocator.rs

@@ -1,6 +1,7 @@
 use crate::indexmap::IndexMap;
 
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::temp_v;
 
 use crate::allocator::*;
 use crate::fixtures::*;
@@ -293,9 +294,7 @@ impl<'a> Allocator<'a> for DebrayAllocator {
 
                 (pr, true)
             }
-            r => {
+            r => (r, false),
-                (r, false)
-            }
         };
 
         self.mark_reserved_var(var, lvl, cell, term_loc, target, r, is_new_var);

src/forms.rs

@@ -1,5 +1,6 @@
 use crate::prolog_parser_rebis::ast::*;
 use crate::prolog_parser_rebis::parser::OpDesc;
+use crate::prolog_parser_rebis::{clause_name, is_infix, is_postfix};
 
 use crate::clause_types::*;
 use crate::machine::machine_errors::*;
@@ -36,7 +37,7 @@ pub enum TopLevel {
 #[derive(Debug, Clone, Copy)]
 pub enum AppendOrPrepend {
     Append,
-    Prepend
+    Prepend,
 }
 
 impl AppendOrPrepend {
@@ -115,12 +116,8 @@ impl ListingSource {
 pub trait ClauseInfo {
     fn is_consistent(&self, clauses: &Vec<PredicateClause>) -> bool {
         match clauses.first() {
-            Some(cl) => {
+            Some(cl) => self.name() == cl.name() && self.arity() == cl.arity(),
-                self.name() == cl.name() && self.arity() == cl.arity()
+            None => true,
-            }
-            None => {
-                true
-            }
         }
     }
 
@@ -140,38 +137,25 @@ impl ClauseInfo for Term {
                             _ => Some(clause_name!(":-")),
                         }
                     }
-                    _ => {
+                    _ => Some(name.clone()),
-                        Some(name.clone())
-                    }
                 }
             }
-            Term::Constant(_, Constant::Atom(ref name, _)) => {
+            Term::Constant(_, Constant::Atom(ref name, _)) => Some(name.clone()),
-                Some(name.clone())
+            _ => None,
-            }
-            _ => {
-                None
-            }
         }
     }
 
     fn arity(&self) -> usize {
         match self {
-            Term::Clause(_, ref name, ref terms, _) =>
+            Term::Clause(_, ref name, ref terms, _) => match name.as_str() {
-                match name.as_str() {
+                ":-" => match terms.len() {
-                    ":-" => {
+                    1 => 0,
-                        match terms.len() {
+                    2 => terms[0].arity(),
-                            1 => 0,
+                    _ => terms.len(),
-                            2 => terms[0].arity(),
-                            _ => terms.len(),
-                        }
-                    }
-                    _ => {
-                        terms.len()
-                    }
                 },
-            _ => {
+                _ => terms.len(),
-                0
+            },
-            }
+            _ => 0,
         }
     }
 }
@@ -189,23 +173,15 @@ impl ClauseInfo for Rule {
 impl ClauseInfo for PredicateClause {
     fn name(&self) -> Option<ClauseName> {
         match self {
-            &PredicateClause::Fact(ref term, ..) => {
+            &PredicateClause::Fact(ref term, ..) => term.name(),
-                term.name()
+            &PredicateClause::Rule(ref rule, ..) => rule.name(),
-            }
-            &PredicateClause::Rule(ref rule, ..) => {
-                rule.name()
-            }
         }
     }
 
     fn arity(&self) -> usize {
         match self {
-            &PredicateClause::Fact(ref term, ..) => {
+            &PredicateClause::Fact(ref term, ..) => term.arity(),
-                term.arity()
+            &PredicateClause::Rule(ref rule, ..) => rule.arity(),
-            }
-            &PredicateClause::Rule(ref rule, ..) => {
-                rule.arity()
-            }
         }
     }
 }
@@ -222,11 +198,9 @@ impl PredicateClause {
     // TODO: add this to `Term` in `prolog_parser` like `first_arg`.
     pub fn args(&self) -> Option<&[Box<Term>]> {
         match *self {
-            PredicateClause::Fact(ref term, ..) => {
+            PredicateClause::Fact(ref term, ..) => match term {
-                match term {
+                Term::Clause(_, _, args, _) => Some(&args),
-                    Term::Clause(_, _, args, _) => Some(&args),
+                _ => None,
-                    _ => None,
-                }
             },
             PredicateClause::Rule(ref rule, ..) => {
                 if rule.head.1.is_empty() {
@@ -240,14 +214,11 @@ impl PredicateClause {
 
     pub fn arity(&self) -> usize {
         match self {
-            &PredicateClause::Fact(ref term, ..) => {
+            &PredicateClause::Fact(ref term, ..) => term.arity(),
-                term.arity()
-            }
             &PredicateClause::Rule(ref rule, ..) => {
                 if rule.head.0.as_str() == ":" && rule.head.1.len() == 2 {
                     match (rule.head.1)[0].as_ref() {
-                        &Term::Constant(_, Constant::Atom(..)) => {
+                        &Term::Constant(_, Constant::Atom(..)) => {}
-                        }
                         _ => {
                             return 2;
                         }
@@ -321,7 +292,7 @@ pub enum Declaration {
 pub struct OpDecl {
     pub prec: usize,
     pub spec: Specifier,
-    pub name: ClauseName
+    pub name: ClauseName,
 }
 
 impl OpDecl {
@@ -345,7 +316,7 @@ impl OpDecl {
             XFY | XFX | YFX => Fixity::In,
             XF | YF => Fixity::Post,
             FX | FY => Fixity::Pre,
-            _ => unreachable!()
+            _ => unreachable!(),
         }
     }
 
@@ -356,12 +327,12 @@ impl OpDecl {
             Some(cell) => {
                 return Some(cell.shared_op_desc().replace((self.prec, self.spec)));
             }
-            None => {
+            None => {}
-            }
         }
 
-        op_dir.insert(key, OpDirValue::new(self.spec, self.prec))
+        op_dir
-              .map(|op_dir_value| op_dir_value.shared_op_desc().get())
+            .insert(key, OpDirValue::new(self.spec, self.prec))
+            .map(|op_dir_value| op_dir_value.shared_op_desc().get())
     }
 
     pub fn submit(
@@ -419,11 +390,7 @@ pub fn fetch_op_spec_from_existing(
     spec.or_else(|| fetch_op_spec(name, arity, op_dir))
 }
 
-pub fn fetch_op_spec(
+pub fn fetch_op_spec(name: ClauseName, arity: usize, op_dir: &OpDir) -> Option<SharedOpDesc> {
-    name: ClauseName,
-    arity: usize,
-    op_dir: &OpDir,
-) -> Option<SharedOpDesc> {
     match arity {
         2 => op_dir
             .get(&(name, Fixity::In))
@@ -451,9 +418,7 @@ pub fn fetch_op_spec(
                     }
                 })
         }
-        _ => {
+        _ => None,
-            None
-        }
     }
 }
 
@@ -499,7 +464,6 @@ impl Module {
     }
 }
 
-
 #[derive(Debug, Clone)]
 pub enum Number {
     Float(OrderedFloat<f64>),
@@ -559,7 +523,6 @@ impl Into<HeapCellValue> for Number {
     }
 }
 
-
 impl Number {
     #[inline]
     pub fn is_positive(&self) -> bool {
@@ -594,12 +557,13 @@ impl Number {
     #[inline]
     pub fn abs(self) -> Self {
         match self {
-            Number::Fixnum(n) =>
+            Number::Fixnum(n) => {
                 if let Some(n) = n.checked_abs() {
                     Number::from(n)
                 } else {
                     Number::from(Integer::from(n).abs())
                 }
+            }
             Number::Integer(n) => Number::from(Integer::from(n.abs_ref())),
             Number::Float(f) => Number::Float(OrderedFloat(f.abs())),
             Number::Rational(r) => Number::from(Rational::from(r.abs_ref())),
@@ -624,15 +588,13 @@ impl OptArgIndexKey {
     #[inline]
     pub fn arg_num(&self) -> usize {
         match &self {
-            OptArgIndexKey::Constant(arg_num, ..) |
+            OptArgIndexKey::Constant(arg_num, ..)
-            OptArgIndexKey::Structure(arg_num, ..) |
+            | OptArgIndexKey::Structure(arg_num, ..)
-            OptArgIndexKey::List(arg_num, _) => {
+            | OptArgIndexKey::List(arg_num, _) => {
                 // these are always at least 1.
                 *arg_num
             }
-            OptArgIndexKey::None => {
+            OptArgIndexKey::None => 0,
-                0
-            }
         }
     }
 
@@ -644,27 +606,22 @@ impl OptArgIndexKey {
     #[inline]
     pub fn switch_on_term_loc(&self) -> Option<usize> {
         match &self {
-            OptArgIndexKey::Constant(_, loc, ..) |
+            OptArgIndexKey::Constant(_, loc, ..)
-            OptArgIndexKey::Structure(_, loc, ..) |
+            | OptArgIndexKey::Structure(_, loc, ..)
-            OptArgIndexKey::List(_, loc) => {
+            | OptArgIndexKey::List(_, loc) => Some(*loc),
-                Some(*loc)
+            OptArgIndexKey::None => None,
-            }
-            OptArgIndexKey::None => {
-                None
-            }
         }
     }
 
     #[inline]
     pub fn set_switch_on_term_loc(&mut self, value: usize) {
         match self {
-            OptArgIndexKey::Constant(_, ref mut loc, ..) |
+            OptArgIndexKey::Constant(_, ref mut loc, ..)
-            OptArgIndexKey::Structure(_, ref mut loc, ..) |
+            | OptArgIndexKey::Structure(_, ref mut loc, ..)
-            OptArgIndexKey::List(_, ref mut loc) => {
+            | OptArgIndexKey::List(_, ref mut loc) => {
                 *loc = value;
             }
-            OptArgIndexKey::None => {
+            OptArgIndexKey::None => {}
-            }
         }
     }
 }
@@ -673,13 +630,12 @@ impl AddAssign<usize> for OptArgIndexKey {
     #[inline]
     fn add_assign(&mut self, n: usize) {
         match self {
-            OptArgIndexKey::Constant(_, ref mut o, ..) |
+            OptArgIndexKey::Constant(_, ref mut o, ..)
-            OptArgIndexKey::List(_, ref mut o) |
+            | OptArgIndexKey::List(_, ref mut o)
-            OptArgIndexKey::Structure(_, ref mut o, ..) => {
+            | OptArgIndexKey::Structure(_, ref mut o, ..) => {
                 *o += n;
             }
-            OptArgIndexKey::None => {
+            OptArgIndexKey::None => {}
-            }
         }
     }
 }

src/heap_print.rs

@@ -1,4 +1,10 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::{
+    alpha_char, alpha_numeric_char, backslash_char, capital_letter_char, char_class, clause_name,
+    cut_char, decimal_digit_char, graphic_char, graphic_token_char, is_fx, is_infix, is_postfix,
+    is_prefix, is_xf, is_xfx, is_xfy, is_yfx, semicolon_char, sign_char, single_quote_char,
+    small_letter_char, solo_char, variable_indicator_char,
+};
 
 use crate::clause_types::*;
 use crate::forms::*;
@@ -14,7 +20,7 @@ use crate::indexmap::{IndexMap, IndexSet};
 
 use std::cell::Cell;
 use std::convert::TryFrom;
-use std::iter::{FromIterator, once};
+use std::iter::{once, FromIterator};
 use std::net::{IpAddr, TcpListener};
 use std::ops::{Range, RangeFrom};
 use std::rc::Rc;
@@ -99,10 +105,7 @@ impl<'a> HCPreOrderIterator<'a> {
             None => return false,
         };
 
-        let mut parent_spec = DirectedOp::Left(
+        let mut parent_spec = DirectedOp::Left(clause_name!("-"), SharedOpDesc::new(200, FY));
-            clause_name!("-"),
-            SharedOpDesc::new(200, FY),
-        );
 
         loop {
             match self.machine_st.store(self.machine_st.deref(addr)) {
@@ -154,12 +157,13 @@ fn char_to_string(is_quoted: bool, c: char) -> String {
         '\u{07}' if is_quoted => "\\a".to_string(), // UTF-8 alert
         '"' if is_quoted => "\\\"".to_string(),
         '\\' if is_quoted => "\\\\".to_string(),
-        '\'' | '\n' | '\r' | '\t' | '\u{0b}' | '\u{0c}' | '\u{08}' | '\u{07}' | '"' | '\\' =>
+        '\'' | '\n' | '\r' | '\t' | '\u{0b}' | '\u{0c}' | '\u{08}' | '\u{07}' | '"' | '\\' => {
-            c.to_string(),
+            c.to_string()
-        '\u{a0}' ..= '\u{d6}' => c.to_string(),
+        }
-        '\u{d8}' ..= '\u{f6}' => c.to_string(),
+        '\u{a0}'..='\u{d6}' => c.to_string(),
-        '\u{f8}' ..= '\u{74f}' => c.to_string(),
+        '\u{d8}'..='\u{f6}' => c.to_string(),
-        '\x20' ..= '\x7e' => c.to_string(),
+        '\u{f8}'..='\u{74f}' => c.to_string(),
+        '\x20'..='\x7e' => c.to_string(),
         _ => format!("\\x{:x}\\", c as u32),
     }
 }
@@ -271,25 +275,13 @@ fn is_numbered_var(ct: &ClauseType, arity: usize) -> bool {
 #[inline]
 fn negated_op_needs_bracketing(iter: &HCPreOrderIterator, op: &Option<DirectedOp>) -> bool {
     if let Some(ref op) = op {
-        op.is_negative_sign() &&
+        op.is_negative_sign()
-            iter.leftmost_leaf_has_property(|addr, heap| {
+            && iter.leftmost_leaf_has_property(|addr, heap| match Number::try_from((addr, heap)) {
-                match Number::try_from((addr, heap)) {
+                Ok(Number::Fixnum(n)) => n > 0,
-                    Ok(Number::Fixnum(n)) => {
+                Ok(Number::Float(f)) => f > OrderedFloat(0f64),
-                        n > 0
+                Ok(Number::Integer(n)) => &*n > &0,
-                    }
+                Ok(Number::Rational(n)) => &*n > &0,
-                    Ok(Number::Float(f)) => {
+                _ => false,
-                        f > OrderedFloat(0f64)
-                    }
-                    Ok(Number::Integer(n)) => {
-                        &*n > &0
-                    }
-                    Ok(Number::Rational(n)) => {
-                        &*n > &0
-                    }
-                    _ => {
-                        false
-                    }
-                }
             })
     } else {
         false
@@ -298,8 +290,8 @@ fn negated_op_needs_bracketing(iter: &HCPreOrderIterator, op: &Option<DirectedOp
 
 fn numbervar(n: Integer) -> Var {
     static CHAR_CODES: [char; 26] = [
-        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
+        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
-        'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
+        'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
     ];
 
     let i = n.mod_u(26) as usize;
@@ -332,9 +324,7 @@ impl MachineState {
                     None
                 }
             }
-            _ => {
+            _ => None,
-                None
-            }
         }
     }
 }
@@ -446,8 +436,7 @@ fn non_quoted_graphic_token<Iter: Iterator<Item = char>>(mut iter: Iter, c: char
     }
 }
 
-pub(super)
+pub(super) fn non_quoted_token<Iter: Iterator<Item = char>>(mut iter: Iter) -> bool {
-fn non_quoted_token<Iter: Iterator<Item = char>>(mut iter: Iter) -> bool {
     if let Some(c) = iter.next() {
         if small_letter_char!(c) {
             iter.all(|c| alpha_numeric_char!(c))
@@ -505,37 +494,37 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
             max_depth: 0,
         }
     }
-/*
+    /*
-    pub fn from_heap_locs(
+        pub fn from_heap_locs(
-        machine_st: &'a MachineState,
+            machine_st: &'a MachineState,
-        op_dir: &'a OpDir,
+            op_dir: &'a OpDir,
-        output: Outputter,
+            output: Outputter,
-    ) -> Self {
+        ) -> Self {
-        let mut printer = Self::new(machine_st, op_dir, output);
+            let mut printer = Self::new(machine_st, op_dir, output);
 
-        printer.toplevel_spec = Some(DirectedOp::Right(
+            printer.toplevel_spec = Some(DirectedOp::Right(
-            clause_name!("="),
+                clause_name!("="),
-            SharedOpDesc::new(700, XFX),
+                SharedOpDesc::new(700, XFX),
-        ));
+            ));
 
-        printer.heap_locs = reverse_heap_locs(machine_st);
+            printer.heap_locs = reverse_heap_locs(machine_st);
 
-        printer
+            printer
-    }
-*/
-/*
-    pub fn drop_toplevel_spec(&mut self) {
-        self.toplevel_spec = None;
-    }
-*/
-/*
-    #[inline]
-    pub fn see_all_locs(&mut self) {
-        for key in self.heap_locs.keys().cloned() {
-            self.printed_vars.insert(key);
         }
-    }
+    */
-*/
+    /*
+        pub fn drop_toplevel_spec(&mut self) {
+            self.toplevel_spec = None;
+        }
+    */
+    /*
+        #[inline]
+        pub fn see_all_locs(&mut self) {
+            for key in self.heap_locs.keys().cloned() {
+                self.printed_vars.insert(key);
+            }
+        }
+    */
 
     #[inline]
     fn ambiguity_check(&self, atom: &str) -> bool {
@@ -555,7 +544,8 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                 iter.stack().pop();
 
                 self.state_stack.push(TokenOrRedirect::Op(ct.name(), spec));
-                self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+                self.state_stack
+                    .push(TokenOrRedirect::Atom(clause_name!("...")));
 
                 return;
             }
@@ -579,7 +569,8 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
             if self.check_max_depth(&mut max_depth) {
                 iter.stack().pop();
 
-                self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+                self.state_stack
+                    .push(TokenOrRedirect::Atom(clause_name!("...")));
                 self.state_stack.push(TokenOrRedirect::Op(ct.name(), spec));
 
                 return;
@@ -587,7 +578,10 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
             let left_directed_op = DirectedOp::Left(ct.name(), spec.clone());
 
-            self.state_stack.push(TokenOrRedirect::CompositeRedirect(max_depth, left_directed_op));
+            self.state_stack.push(TokenOrRedirect::CompositeRedirect(
+                max_depth,
+                left_directed_op,
+            ));
             self.state_stack.push(TokenOrRedirect::Op(ct.name(), spec));
         } else {
             match ct.name().as_str() {
@@ -602,9 +596,11 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                 iter.stack().pop();
                 iter.stack().pop();
 
-                self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+                self.state_stack
+                    .push(TokenOrRedirect::Atom(clause_name!("...")));
                 self.state_stack.push(TokenOrRedirect::Op(ct.name(), spec));
-                self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+                self.state_stack
+                    .push(TokenOrRedirect::Atom(clause_name!("...")));
 
                 return;
             }
@@ -612,11 +608,15 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
             let left_directed_op = DirectedOp::Left(ct.name(), spec.clone());
             let right_directed_op = DirectedOp::Right(ct.name(), spec.clone());
 
-            self.state_stack
+            self.state_stack.push(TokenOrRedirect::CompositeRedirect(
-                .push(TokenOrRedirect::CompositeRedirect(max_depth, left_directed_op));
+                max_depth,
+                left_directed_op,
+            ));
             self.state_stack.push(TokenOrRedirect::Op(ct.name(), spec));
-            self.state_stack
+            self.state_stack.push(TokenOrRedirect::CompositeRedirect(
-                .push(TokenOrRedirect::CompositeRedirect(max_depth, right_directed_op));
+                max_depth,
+                right_directed_op,
+            ));
         }
     }
 
@@ -626,15 +626,15 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         mut max_depth: usize,
         arity: usize,
         name: ClauseName,
-    ) -> bool
+    ) -> bool {
-    {
         if self.check_max_depth(&mut max_depth) {
-            for _ in 0 .. arity {
+            for _ in 0..arity {
                 iter.stack().pop();
             }
 
             self.state_stack.push(TokenOrRedirect::Close);
-            self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+            self.state_stack
+                .push(TokenOrRedirect::Atom(clause_name!("...")));
             self.state_stack.push(TokenOrRedirect::Open);
 
             self.state_stack.push(TokenOrRedirect::Atom(name));
@@ -644,8 +644,9 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
         self.state_stack.push(TokenOrRedirect::Close);
 
-        for _ in 0 .. arity {
+        for _ in 0..arity {
-            self.state_stack.push(TokenOrRedirect::FunctorRedirect(max_depth));
+            self.state_stack
+                .push(TokenOrRedirect::FunctorRedirect(max_depth));
             self.state_stack.push(TokenOrRedirect::Comma);
         }
 
@@ -662,12 +663,13 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         iter: &mut HCPreOrderIterator,
         mut max_depth: usize,
         name: ClauseName,
-        spec: SharedOpDesc)
+        spec: SharedOpDesc,
-    {
+    ) {
         if self.check_max_depth(&mut max_depth) {
             iter.stack().pop();
 
-            self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+            self.state_stack
+                .push(TokenOrRedirect::Atom(clause_name!("...")));
             self.state_stack.push(TokenOrRedirect::Space);
             self.state_stack.push(TokenOrRedirect::Atom(name));
 
@@ -676,7 +678,8 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
         let op = DirectedOp::Left(name.clone(), spec);
 
-        self.state_stack.push(TokenOrRedirect::CompositeRedirect(max_depth, op));
+        self.state_stack
+            .push(TokenOrRedirect::CompositeRedirect(max_depth, op));
         self.state_stack.push(TokenOrRedirect::Space);
         self.state_stack.push(TokenOrRedirect::Atom(name));
     }
@@ -687,14 +690,15 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         mut max_depth: usize,
         name: ClauseName,
         spec: SharedOpDesc,
-    )
+    ) {
-    {
         if self.check_max_depth(&mut max_depth) {
             iter.stack().pop();
 
-            self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+            self.state_stack
+                .push(TokenOrRedirect::Atom(clause_name!("...")));
             self.state_stack.push(TokenOrRedirect::BarAsOp);
-            self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+            self.state_stack
+                .push(TokenOrRedirect::Atom(clause_name!("...")));
 
             return;
         }
@@ -702,25 +706,32 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         let left_directed_op = DirectedOp::Left(name.clone(), spec.clone());
         let right_directed_op = DirectedOp::Right(name.clone(), spec.clone());
 
-        self.state_stack.push(TokenOrRedirect::CompositeRedirect(max_depth, left_directed_op));
+        self.state_stack.push(TokenOrRedirect::CompositeRedirect(
+            max_depth,
+            left_directed_op,
+        ));
         self.state_stack.push(TokenOrRedirect::BarAsOp);
-        self.state_stack.push(TokenOrRedirect::CompositeRedirect(max_depth, right_directed_op));
+        self.state_stack.push(TokenOrRedirect::CompositeRedirect(
+            max_depth,
+            right_directed_op,
+        ));
     }
 
-    fn format_curly_braces(&mut self, iter: &mut HCPreOrderIterator, mut max_depth: usize) -> bool
+    fn format_curly_braces(&mut self, iter: &mut HCPreOrderIterator, mut max_depth: usize) -> bool {
-    {
         if self.check_max_depth(&mut max_depth) {
             iter.stack().pop();
 
             self.state_stack.push(TokenOrRedirect::RightCurly);
-            self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+            self.state_stack
+                .push(TokenOrRedirect::Atom(clause_name!("...")));
             self.state_stack.push(TokenOrRedirect::LeftCurly);
 
             return false;
         }
 
         self.state_stack.push(TokenOrRedirect::RightCurly);
-        self.state_stack.push(TokenOrRedirect::FunctorRedirect(max_depth));
+        self.state_stack
+            .push(TokenOrRedirect::FunctorRedirect(max_depth));
         self.state_stack.push(TokenOrRedirect::LeftCurly);
 
         true
@@ -795,18 +806,12 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         }
 
         match addr {
-            Addr::Lis(h) | Addr::Str(h) => {
+            Addr::Lis(h) | Addr::Str(h) => Some(format!("{}", h)),
-                Some(format!("{}", h))
-            }
             _ => {
                 if let Some(r) = addr.as_var() {
                     match r {
-                        Ref::StackCell(fr, sc) => {
+                        Ref::StackCell(fr, sc) => Some(format!("_s_{}_{}", fr, sc)),
-                            Some(format!("_s_{}_{}", fr, sc))
+                        Ref::HeapCell(h) | Ref::AttrVar(h) => Some(format!("_{}", h)),
-                        }
-                        Ref::HeapCell(h) | Ref::AttrVar(h) => {
-                            Some(format!("_{}", h))
-                        }
                     }
                 } else {
                     None
@@ -818,8 +823,12 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
     fn record_children_as_non_cyclic(&mut self, addr: &Addr) {
         match addr {
             &Addr::Lis(l) => {
-                let c1 = self.machine_st.store(self.machine_st.deref(Addr::HeapCell(l)));
+                let c1 = self
-                let c2 = self.machine_st.store(self.machine_st.deref(Addr::HeapCell(l + 1)));
+                    .machine_st
+                    .store(self.machine_st.deref(Addr::HeapCell(l)));
+                let c2 = self
+                    .machine_st
+                    .store(self.machine_st.deref(Addr::HeapCell(l + 1)));
 
                 if let Some(c) = functor_location(&c1) {
                     self.non_cyclic_terms.insert(c);
@@ -830,18 +839,17 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                 }
             }
             &Addr::Str(s) => {
-                let arity =
+                let arity = match &self.machine_st.heap[s] {
-                    match &self.machine_st.heap[s] {
+                    HeapCellValue::NamedStr(arity, ..) => arity,
-                        HeapCellValue::NamedStr(arity, ..) => {
+                    _ => {
-                            arity
+                        unreachable!()
-                        }
+                    }
-                        _ => {
+                };
-                            unreachable!()
-                        }
-                    };
 
-                for i in 1 .. arity + 1 {
+                for i in 1..arity + 1 {
-                    let c = self.machine_st.store(self.machine_st.deref(Addr::HeapCell(s + i)));
+                    let c = self
+                        .machine_st
+                        .store(self.machine_st.deref(Addr::HeapCell(s + i)));
 
                     if let Some(c) = functor_location(&c) {
                         self.non_cyclic_terms.insert(c);
@@ -856,15 +864,11 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                     self.non_cyclic_terms.insert(c);
                 }
             }
-            _ => {
+            _ => {}
-            }
         }
     }
 
-    fn check_for_seen(
+    fn check_for_seen(&mut self, iter: &mut HCPreOrderIterator) -> Option<Addr> {
-        &mut self,
-        iter: &mut HCPreOrderIterator,
-    ) -> Option<Addr> {
         iter.stack().last().cloned().and_then(|addr| {
             let addr = self.machine_st.store(self.machine_st.deref(addr));
 
@@ -889,9 +893,7 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                 }
                 None => {
                     let offset = match functor_location(&addr) {
-                        Some(offset) => {
+                        Some(offset) => offset,
-                            offset
-                        }
                         None => {
                             return iter.next();
                         }
@@ -1036,19 +1038,17 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
                 let rdiv_ct = clause_name!("rdiv");
 
-                let left_directed_op =
+                let left_directed_op = if spec.prec() > 0 {
-                    if spec.prec() > 0 {
+                    Some(DirectedOp::Left(rdiv_ct.clone(), spec.clone()))
-                        Some(DirectedOp::Left(rdiv_ct.clone(), spec.clone()))
+                } else {
-                    } else {
+                    None
-                        None
+                };
-                    };
 
-                let right_directed_op =
+                let right_directed_op = if spec.prec() > 0 {
-                    if spec.prec() > 0 {
+                    Some(DirectedOp::Right(rdiv_ct.clone(), spec.clone()))
-                        Some(DirectedOp::Right(rdiv_ct.clone(), spec.clone()))
+                } else {
-                    } else {
+                    None
-                        None
+                };
-                    };
 
                 if spec.prec() > 0 {
                     self.state_stack.push(TokenOrRedirect::Number(
@@ -1056,10 +1056,8 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                         left_directed_op,
                     ));
 
-                    self.state_stack.push(TokenOrRedirect::Op(
+                    self.state_stack
-                        rdiv_ct,
+                        .push(TokenOrRedirect::Op(rdiv_ct, spec.clone()));
-                        spec.clone(),
-                    ));
 
                     self.state_stack.push(TokenOrRedirect::Number(
                         Number::from(r.numer()),
@@ -1068,17 +1066,13 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                 } else {
                     self.state_stack.push(TokenOrRedirect::Close);
 
-                    self.state_stack.push(TokenOrRedirect::Number(
+                    self.state_stack
-                        Number::from(r.denom()),
+                        .push(TokenOrRedirect::Number(Number::from(r.denom()), None));
-                        None,
-                    ));
 
                     self.state_stack.push(TokenOrRedirect::Comma);
 
-                    self.state_stack.push(TokenOrRedirect::Number(
+                    self.state_stack
-                        Number::from(r.numer()),
+                        .push(TokenOrRedirect::Number(Number::from(r.numer()), None));
-                        None,
-                    ));
 
                     self.state_stack.push(TokenOrRedirect::Open);
                     self.state_stack.push(TokenOrRedirect::Atom(rdiv_ct));
@@ -1092,8 +1086,7 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         }
     }
 
-    fn print_char(&mut self, is_quoted: bool, c: char)
+    fn print_char(&mut self, is_quoted: bool, c: char) {
-    {
         if non_quoted_token(once(c)) {
             let c = char_to_string(false, c);
 
@@ -1120,46 +1113,37 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
     fn print_proper_string(&mut self, buf: String, max_depth: usize) {
         self.push_char('"');
 
-        let buf =
+        let buf = if max_depth == 0 {
-            if max_depth == 0 {
+            String::from_iter(buf.chars().map(|c| char_to_string(self.quoted, c)))
-                String::from_iter(buf.chars().map(|c| {
+        } else {
-                    char_to_string(self.quoted, c)
+            let mut char_count = 0;
-                }))
+            let mut buf = String::from_iter(buf.chars().take(max_depth).map(|c| {
-            } else {
+                char_count += 1;
-                let mut char_count = 0;
+                char_to_string(self.quoted, c)
-                let mut buf =
+            }));
-                    String::from_iter(buf.chars().take(max_depth).map(|c| {
-                        char_count += 1;
-                        char_to_string(self.quoted, c)
-                    }));
 
-                if char_count == max_depth {
+            if char_count == max_depth {
-                    buf += " ...";
+                buf += " ...";
-                }
+            }
 
-                buf
+            buf
-            };
+        };
 
         self.append_str(&buf);
         self.push_char('"');
     }
 
-    fn print_list_like(
+    fn print_list_like(&mut self, iter: &mut HCPreOrderIterator, addr: Addr, mut max_depth: usize) {
-        &mut self,
-        iter: &mut HCPreOrderIterator,
-        addr: Addr,
-        mut max_depth: usize,
-    ) {
         if self.check_max_depth(&mut max_depth) {
             iter.stack().pop();
             iter.stack().pop();
 
-            self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+            self.state_stack
+                .push(TokenOrRedirect::Atom(clause_name!("...")));
             return;
         }
 
-        let mut heap_pstr_iter =
+        let mut heap_pstr_iter = self.machine_st.heap_pstr_iter(addr);
-            self.machine_st.heap_pstr_iter(addr);
 
         let buf = heap_pstr_iter.to_string();
 
@@ -1184,12 +1168,11 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
         let buf_len = buf.len();
 
-        let buf_iter: Box<dyn Iterator<Item=char>> =
+        let buf_iter: Box<dyn Iterator<Item = char>> = if self.max_depth == 0 {
-            if self.max_depth == 0 {
+            Box::new(buf.chars())
-                Box::new(buf.chars())
+        } else {
-            } else {
+            Box::new(buf.chars().take(max_depth))
-                Box::new(buf.chars().take(max_depth))
+        };
-            };
 
         let mut byte_len = 0;
 
@@ -1207,14 +1190,16 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                 byte_len += c.len_utf8();
             }
 
-            for _ in 0 .. char_count {
+            for _ in 0..char_count {
                 self.state_stack.push(TokenOrRedirect::Close);
             }
 
             if self.max_depth > 0 && buf_len > byte_len {
-                self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+                self.state_stack
+                    .push(TokenOrRedirect::Atom(clause_name!("...")));
             } else {
-                self.state_stack.push(TokenOrRedirect::FunctorRedirect(max_depth));
+                self.state_stack
+                    .push(TokenOrRedirect::FunctorRedirect(max_depth));
                 iter.stack().push(end_addr);
             }
         } else {
@@ -1232,15 +1217,17 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                 byte_len += c.len_utf8();
             }
 
-            self.state_stack.push(TokenOrRedirect::CloseList(Rc::new(
+            self.state_stack
-                Cell::new((switch, 0))
+                .push(TokenOrRedirect::CloseList(Rc::new(Cell::new((switch, 0)))));
-            )));
 
             if self.max_depth > 0 && buf_len > byte_len {
-                self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+                self.state_stack
-            }  else {
+                    .push(TokenOrRedirect::Atom(clause_name!("...")));
-                self.outputter.truncate(self.outputter.len() - ','.len_utf8());
+            } else {
-                self.state_stack.push(TokenOrRedirect::FunctorRedirect(max_depth));
+                self.outputter
+                    .truncate(self.outputter.len() - ','.len_utf8());
+                self.state_stack
+                    .push(TokenOrRedirect::FunctorRedirect(max_depth));
 
                 iter.stack().push(end_addr);
             }
@@ -1268,8 +1255,10 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
             let cell = Rc::new(Cell::new((true, 0)));
 
-            self.state_stack.push(TokenOrRedirect::CloseList(cell.clone()));
+            self.state_stack
-            self.state_stack.push(TokenOrRedirect::Atom(clause_name!("...")));
+                .push(TokenOrRedirect::CloseList(cell.clone()));
+            self.state_stack
+                .push(TokenOrRedirect::Atom(clause_name!("...")));
             self.state_stack.push(TokenOrRedirect::OpenList(cell));
 
             return;
@@ -1277,11 +1266,14 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
         let cell = Rc::new(Cell::new((true, max_depth)));
 
-        self.state_stack.push(TokenOrRedirect::CloseList(cell.clone()));
+        self.state_stack
+            .push(TokenOrRedirect::CloseList(cell.clone()));
 
-        self.state_stack.push(TokenOrRedirect::FunctorRedirect(max_depth));
+        self.state_stack
+            .push(TokenOrRedirect::FunctorRedirect(max_depth));
         self.state_stack.push(TokenOrRedirect::HeadTailSeparator); // bar
-        self.state_stack.push(TokenOrRedirect::FunctorRedirect(max_depth));
+        self.state_stack
+            .push(TokenOrRedirect::FunctorRedirect(max_depth));
 
         self.state_stack.push(TokenOrRedirect::OpenList(cell));
     }
@@ -1298,23 +1290,24 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         max_depth: usize,
     ) {
         let add_brackets = if !self.ignore_ops {
-            negated_operand || if let Some(ref op) = op {
+            negated_operand
-                if self.numbervars && arity == 1 && name.as_str() == "$VAR" {
+                || if let Some(ref op) = op {
-                    !iter.immediate_leaf_has_property(|addr, heap| {
+                    if self.numbervars && arity == 1 && name.as_str() == "$VAR" {
-                        match heap.index_addr(&addr).as_ref() {
+                        !iter.immediate_leaf_has_property(|addr, heap| {
-                            &HeapCellValue::Integer(ref n) => &**n >= &0,
+                            match heap.index_addr(&addr).as_ref() {
-                            &HeapCellValue::Addr(Addr::Fixnum(n)) => n >= 0,
+                                &HeapCellValue::Integer(ref n) => &**n >= &0,
-                            &HeapCellValue::Addr(Addr::Float(f)) => f >= OrderedFloat(0f64),
+                                &HeapCellValue::Addr(Addr::Fixnum(n)) => n >= 0,
-                            &HeapCellValue::Rational(ref r) => &**r >= &0,
+                                &HeapCellValue::Addr(Addr::Float(f)) => f >= OrderedFloat(0f64),
-                            _ => false
+                                &HeapCellValue::Rational(ref r) => &**r >= &0,
-                        }
+                                _ => false,
-                    }) && needs_bracketing(&spec, op)
+                            }
+                        }) && needs_bracketing(&spec, op)
+                    } else {
+                        needs_bracketing(&spec, op)
+                    }
                 } else {
-                    needs_bracketing(&spec, op)
+                    is_functor_redirect && spec.prec() >= 1000
                 }
-            } else {
-                is_functor_redirect && spec.prec() >= 1000
-            }
         } else {
             false
         };
@@ -1344,15 +1337,15 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         tcp_listener: &TcpListener,
         max_depth: usize,
     ) {
-        let (ip, port) =
+        let (ip, port) = if let Some(addr) = tcp_listener.local_addr().ok() {
-            if let Some(addr) = tcp_listener.local_addr().ok() {
+            (addr.ip(), Number::from(addr.port() as isize))
-                (addr.ip(), Number::from(addr.port() as isize))
+        } else {
-            } else {
+            let disconnected_atom = clause_name!("$disconnected_tcp_listener");
-                let disconnected_atom = clause_name!("$disconnected_tcp_listener");
+            self.state_stack
-                self.state_stack.push(TokenOrRedirect::Atom(disconnected_atom));
+                .push(TokenOrRedirect::Atom(disconnected_atom));
 
-                return;
+            return;
-            };
+        };
 
         if self.format_struct(iter, max_depth, 1, clause_name!("$tcp_listener")) {
             let atom = self.state_stack.pop().unwrap();
@@ -1369,22 +1362,16 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         }
     }
 
-    fn print_stream(
+    fn print_stream(&mut self, iter: &mut HCPreOrderIterator, stream: &Stream, max_depth: usize) {
-        &mut self,
-        iter: &mut HCPreOrderIterator,
-        stream: &Stream,
-        max_depth: usize,
-    ) {
         if let Some(alias) = &stream.options.alias {
             self.print_atom(alias);
         } else {
             if self.format_struct(iter, max_depth, 1, clause_name!("$stream")) {
-                let atom =
+                let atom = if stream.is_stdout() || stream.is_stdin() {
-                    if stream.is_stdout() || stream.is_stdin() {
+                    TokenOrRedirect::Atom(clause_name!("user"))
-                        TokenOrRedirect::Atom(clause_name!("user"))
+                } else {
-                    } else {
+                    TokenOrRedirect::RawPtr(stream.as_ptr())
-                        TokenOrRedirect::RawPtr(stream.as_ptr())
+                };
-                    };
 
                 let stream_root = self.state_stack.pop().unwrap();
 
@@ -1414,7 +1401,8 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
         match self.machine_st.heap.index_addr(&addr).as_ref() {
             &HeapCellValue::NamedStr(arity, ref name, ref spec) => {
-                let spec = fetch_op_spec_from_existing(name.clone(), arity, spec.clone(), self.op_dir);
+                let spec =
+                    fetch_op_spec_from_existing(name.clone(), arity, spec.clone(), self.op_dir);
 
                 if let Some(spec) = spec {
                     self.handle_op_as_struct(

src/indexing.rs

@@ -1,4 +1,5 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::clause_name;
 use crate::prolog_parser_rebis::tabled_rc::*;
 
 use crate::forms::*;
@@ -43,14 +44,10 @@ impl OptArgIndexKey {
     #[inline]
     fn has_key_type(&self, key_type: OptArgIndexKeyType) -> bool {
         match (self, key_type) {
-            (OptArgIndexKey::Constant(..), OptArgIndexKeyType::Constant) |
+            (OptArgIndexKey::Constant(..), OptArgIndexKeyType::Constant)
-            (OptArgIndexKey::Structure(..), OptArgIndexKeyType::Structure) |
+            | (OptArgIndexKey::Structure(..), OptArgIndexKeyType::Structure)
-            (OptArgIndexKey::List(..), OptArgIndexKeyType::List) => {
+            | (OptArgIndexKey::List(..), OptArgIndexKeyType::List) => true,
-                true
+            _ => false,
-            }
-            _ => {
-                false
-            }
         }
     }
 }
@@ -93,16 +90,20 @@ impl<'a> IndexingCodeMergingPtr<'a> {
         indexing_code: &'a mut Vec<IndexingLine>,
         append_or_prepend: AppendOrPrepend,
     ) -> Self {
-        Self { skeleton, indexing_code, offset: 0, append_or_prepend }
+        Self {
+            skeleton,
+            indexing_code,
+            offset: 0,
+            append_or_prepend,
+        }
     }
 
-    fn internalize_constant(&mut self, constant_ptr: IndexingCodePtr)  {
+    fn internalize_constant(&mut self, constant_ptr: IndexingCodePtr) {
-        let constant_key =
+        let constant_key = search_skeleton_for_first_key_type(
-            search_skeleton_for_first_key_type(
+            self.skeleton,
-                self.skeleton,
+            OptArgIndexKeyType::Constant,
-                OptArgIndexKeyType::Constant,
+            self.append_or_prepend,
-                self.append_or_prepend,
+        );
-            );
 
         let mut constants = IndexMap::new();
 
@@ -117,7 +118,7 @@ impl<'a> IndexingCodeMergingPtr<'a> {
 
         if let IndexingCodePtr::Internal(_) = constant_ptr {
             self.indexing_code.push(IndexingLine::Indexing(
-                IndexingInstruction::SwitchOnConstant(constants)
+                IndexingInstruction::SwitchOnConstant(constants),
             ));
 
             let last_index = self.indexing_code.len() - 1;
@@ -126,34 +127,39 @@ impl<'a> IndexingCodeMergingPtr<'a> {
             self.offset = self.indexing_code.len();
 
             self.indexing_code.push(IndexingLine::Indexing(
-                IndexingInstruction::SwitchOnConstant(constants)
+                IndexingInstruction::SwitchOnConstant(constants),
             ));
         }
     }
 
-    fn add_indexed_choice_for_constant(&mut self, external: usize, constant: Constant, index: usize)
+    fn add_indexed_choice_for_constant(
-    {
+        &mut self,
-        let third_level_index =
+        external: usize,
-            if self.append_or_prepend.is_append() {
+        constant: Constant,
-                sdeq![
+        index: usize,
-                    IndexedChoiceInstruction::Try(external),
+    ) {
-                    IndexedChoiceInstruction::Trust(index)
+        let third_level_index = if self.append_or_prepend.is_append() {
-                ]
+            sdeq![
-            } else {
+                IndexedChoiceInstruction::Try(external),
-                sdeq![
+                IndexedChoiceInstruction::Trust(index)
-                    IndexedChoiceInstruction::Try(index),
+            ]
-                    IndexedChoiceInstruction::Trust(external)
+        } else {
-                ]
+            sdeq![
-            };
+                IndexedChoiceInstruction::Try(index),
+                IndexedChoiceInstruction::Trust(external)
+            ]
+        };
 
         let indexing_code_len = self.indexing_code.len();
-        self.indexing_code.push(IndexingLine::IndexedChoice(third_level_index));
+        self.indexing_code
+            .push(IndexingLine::IndexedChoice(third_level_index));
 
         match &mut self.indexing_code[self.offset] {
-            IndexingLine::Indexing(
+            IndexingLine::Indexing(IndexingInstruction::SwitchOnConstant(ref mut constants)) => {
-                IndexingInstruction::SwitchOnConstant(ref mut constants)
+                constants.insert(
-            ) => {
+                    constant,
-                constants.insert(constant, IndexingCodePtr::Internal(indexing_code_len - self.offset));
+                    IndexingCodePtr::Internal(indexing_code_len - self.offset),
+                );
             }
             _ => {
                 unreachable!()
@@ -164,10 +170,11 @@ impl<'a> IndexingCodeMergingPtr<'a> {
     fn extend_indexed_choice(&mut self, index: usize) {
         match &mut self.indexing_code[self.offset] {
             IndexingLine::IndexedChoice(ref mut indexed_choice_instrs)
-                if self.append_or_prepend.is_append() => {
+                if self.append_or_prepend.is_append() =>
-                    uncap_choice_seq_with_trust(indexed_choice_instrs);
+            {
-                    indexed_choice_instrs.push_back(IndexedChoiceInstruction::Trust(index));
+                uncap_choice_seq_with_trust(indexed_choice_instrs);
-                }
+                indexed_choice_instrs.push_back(IndexedChoiceInstruction::Trust(index));
+            }
             IndexingLine::IndexedChoice(ref mut indexed_choice_instrs) => {
                 uncap_choice_seq_with_try(indexed_choice_instrs);
                 indexed_choice_instrs.push_front(IndexedChoiceInstruction::Try(index));
@@ -188,9 +195,7 @@ impl<'a> IndexingCodeMergingPtr<'a> {
             let indexing_code_len = self.indexing_code.len();
 
             match &mut self.indexing_code[self.offset] {
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)) => {
-                    IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)
-                ) => {
                     match *c {
                         IndexingCodePtr::Fail => {
                             *c = IndexingCodePtr::External(index);
@@ -203,7 +208,7 @@ impl<'a> IndexingCodeMergingPtr<'a> {
                             *c = IndexingCodePtr::Internal(indexing_code_len);
 
                             self.indexing_code.push(IndexingLine::Indexing(
-                                IndexingInstruction::SwitchOnConstant(constants)
+                                IndexingInstruction::SwitchOnConstant(constants),
                             ));
 
                             self.offset = indexing_code_len;
@@ -213,12 +218,11 @@ impl<'a> IndexingCodeMergingPtr<'a> {
                         }
                     }
                 }
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnConstant(constants)) => {
-                    IndexingInstruction::SwitchOnConstant(constants)
-                ) => {
                     match constants.get(&overlapping_constant).cloned() {
                         None | Some(IndexingCodePtr::Fail) => {
-                            constants.insert(overlapping_constant, IndexingCodePtr::External(index));
+                            constants
+                                .insert(overlapping_constant, IndexingCodePtr::External(index));
                         }
                         Some(IndexingCodePtr::External(o)) => {
                             self.add_indexed_choice_for_constant(o, overlapping_constant, index);
@@ -232,9 +236,9 @@ impl<'a> IndexingCodeMergingPtr<'a> {
                     break;
                 }
                 IndexingLine::IndexedChoice(_) => {
-                    self.internalize_constant(
+                    self.internalize_constant(IndexingCodePtr::Internal(
-                        IndexingCodePtr::Internal(indexing_code_len - self.offset),
+                        indexing_code_len - self.offset,
-                    );
+                    ));
                 }
                 _ => {
                     unreachable!()
@@ -248,9 +252,7 @@ impl<'a> IndexingCodeMergingPtr<'a> {
             let indexing_code_len = self.indexing_code.len();
 
             match &mut self.indexing_code[self.offset] {
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)) => {
-                    IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)
-                ) => {
                     match *c {
                         IndexingCodePtr::Fail => {
                             *c = IndexingCodePtr::External(index);
@@ -265,9 +267,7 @@ impl<'a> IndexingCodeMergingPtr<'a> {
                         }
                     }
                 }
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnConstant(constants)) => {
-                    IndexingInstruction::SwitchOnConstant(constants)
-                ) => {
                     match constants.get(&constant).cloned() {
                         None | Some(IndexingCodePtr::Fail) => {
                             constants.insert(constant, IndexingCodePtr::External(index));
@@ -284,9 +284,9 @@ impl<'a> IndexingCodeMergingPtr<'a> {
                     break;
                 }
                 IndexingLine::IndexedChoice(_) => {
-                    self.internalize_constant(
+                    self.internalize_constant(IndexingCodePtr::Internal(
-                        IndexingCodePtr::Internal(indexing_code_len - self.offset),
+                        indexing_code_len - self.offset,
-                    );
+                    ));
                 }
                 _ => {
                     unreachable!()
@@ -295,13 +295,12 @@ impl<'a> IndexingCodeMergingPtr<'a> {
         }
     }
 
-    fn internalize_structure(&mut self, structure_ptr: IndexingCodePtr)  {
+    fn internalize_structure(&mut self, structure_ptr: IndexingCodePtr) {
-        let structure_key =
+        let structure_key = search_skeleton_for_first_key_type(
-            search_skeleton_for_first_key_type(
+            self.skeleton,
-                self.skeleton,
+            OptArgIndexKeyType::Structure,
-                OptArgIndexKeyType::Structure,
+            self.append_or_prepend,
-                self.append_or_prepend,
+        );
-            );
 
         let mut structures = IndexMap::new();
 
@@ -316,7 +315,7 @@ impl<'a> IndexingCodeMergingPtr<'a> {
 
         if let IndexingCodePtr::Internal(_) = structure_ptr {
             self.indexing_code.push(IndexingLine::Indexing(
-                IndexingInstruction::SwitchOnStructure(structures)
+                IndexingInstruction::SwitchOnStructure(structures),
             ));
 
             let last_index = self.indexing_code.len() - 1;
@@ -325,34 +324,39 @@ impl<'a> IndexingCodeMergingPtr<'a> {
             self.offset = self.indexing_code.len();
 
             self.indexing_code.push(IndexingLine::Indexing(
-                IndexingInstruction::SwitchOnStructure(structures)
+                IndexingInstruction::SwitchOnStructure(structures),
             ));
         }
     }
 
-    fn add_indexed_choice_for_structure(&mut self, external: usize, key: PredicateKey, index: usize)
+    fn add_indexed_choice_for_structure(
-    {
+        &mut self,
-        let third_level_index =
+        external: usize,
-            if self.append_or_prepend.is_append() {
+        key: PredicateKey,
-                sdeq![
+        index: usize,
-                    IndexedChoiceInstruction::Try(external),
+    ) {
-                    IndexedChoiceInstruction::Trust(index)
+        let third_level_index = if self.append_or_prepend.is_append() {
-                ]
+            sdeq![
-            } else {
+                IndexedChoiceInstruction::Try(external),
-                sdeq![
+                IndexedChoiceInstruction::Trust(index)
-                    IndexedChoiceInstruction::Try(index),
+            ]
-                    IndexedChoiceInstruction::Trust(external)
+        } else {
-                ]
+            sdeq![
-            };
+                IndexedChoiceInstruction::Try(index),
+                IndexedChoiceInstruction::Trust(external)
+            ]
+        };
 
         let indexing_code_len = self.indexing_code.len();
-        self.indexing_code.push(IndexingLine::IndexedChoice(third_level_index));
+        self.indexing_code
+            .push(IndexingLine::IndexedChoice(third_level_index));
 
         match &mut self.indexing_code[self.offset] {
-            IndexingLine::Indexing(
+            IndexingLine::Indexing(IndexingInstruction::SwitchOnStructure(ref mut structures)) => {
-                IndexingInstruction::SwitchOnStructure(ref mut structures)
+                structures.insert(
-            ) => {
+                    key,
-                structures.insert(key, IndexingCodePtr::Internal(indexing_code_len - self.offset));
+                    IndexingCodePtr::Internal(indexing_code_len - self.offset),
+                );
             }
             _ => {
                 unreachable!()
@@ -365,26 +369,26 @@ impl<'a> IndexingCodeMergingPtr<'a> {
             let indexing_code_len = self.indexing_code.len();
 
             match &mut self.indexing_code[self.offset] {
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(
-                    IndexingInstruction::SwitchOnTerm(_, _, _, _, ref mut s)
+                    _,
-                ) => {
+                    _,
-                    match *s {
+                    _,
-                        IndexingCodePtr::Fail => {
+                    _,
-                            *s = IndexingCodePtr::External(index);
+                    ref mut s,
-                            break;
+                )) => match *s {
-                        }
+                    IndexingCodePtr::Fail => {
-                        IndexingCodePtr::External(o) => {
+                        *s = IndexingCodePtr::External(index);
-                            *s = IndexingCodePtr::Internal(indexing_code_len - self.offset);
+                        break;
-                            self.internalize_structure(IndexingCodePtr::External(o));
-                        }
-                        IndexingCodePtr::Internal(o) => {
-                            self.offset += o;
-                        }
                     }
-                }
+                    IndexingCodePtr::External(o) => {
-                IndexingLine::Indexing(
+                        *s = IndexingCodePtr::Internal(indexing_code_len - self.offset);
-                    IndexingInstruction::SwitchOnStructure(structures)
+                        self.internalize_structure(IndexingCodePtr::External(o));
-                ) => {
+                    }
+                    IndexingCodePtr::Internal(o) => {
+                        self.offset += o;
+                    }
+                },
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnStructure(structures)) => {
                     match structures.get(&key).cloned() {
                         None | Some(IndexingCodePtr::Fail) => {
                             structures.insert(key, IndexingCodePtr::External(index));
@@ -404,9 +408,9 @@ impl<'a> IndexingCodeMergingPtr<'a> {
                     // replace this value, at self.offset, with
                     // SwitchOnStructures, and swap this IndexedChoice
                     // vector to the end of self.indexing_code.
-                    self.internalize_structure(
+                    self.internalize_structure(IndexingCodePtr::Internal(
-                        IndexingCodePtr::Internal(indexing_code_len - self.offset),
+                        indexing_code_len - self.offset,
-                    );
+                    ));
                 }
                 _ => {
                     unreachable!()
@@ -419,9 +423,7 @@ impl<'a> IndexingCodeMergingPtr<'a> {
         let indexing_code_len = self.indexing_code.len();
 
         match &mut self.indexing_code[self.offset] {
-            IndexingLine::Indexing(
+            IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(_, _, _, ref mut l, _)) => {
-                IndexingInstruction::SwitchOnTerm(_, _, _, ref mut l, _)
-            ) => {
                 match *l {
                     IndexingCodePtr::Fail => {
                         *l = IndexingCodePtr::External(index);
@@ -429,22 +431,20 @@ impl<'a> IndexingCodeMergingPtr<'a> {
                     IndexingCodePtr::External(o) => {
                         *l = IndexingCodePtr::Internal(indexing_code_len - self.offset);
 
-                        let third_level_index =
+                        let third_level_index = if self.append_or_prepend.is_append() {
-                            if self.append_or_prepend.is_append() {
+                            sdeq![
-                                sdeq![
+                                IndexedChoiceInstruction::Try(o),
-                                    IndexedChoiceInstruction::Try(o),
+                                IndexedChoiceInstruction::Trust(index)
-                                    IndexedChoiceInstruction::Trust(index)
+                            ]
-                                ]
+                        } else {
-                            } else {
+                            sdeq![
-                                sdeq![
+                                IndexedChoiceInstruction::Try(index),
-                                    IndexedChoiceInstruction::Try(index),
+                                IndexedChoiceInstruction::Trust(o)
-                                    IndexedChoiceInstruction::Trust(o)
+                            ]
-                                ]
+                        };
-                            };
 
-                        self.indexing_code.push(
+                        self.indexing_code
-                            IndexingLine::IndexedChoice(third_level_index),
+                            .push(IndexingLine::IndexedChoice(third_level_index));
-                        );
                     }
                     IndexingCodePtr::Internal(o) => {
                         self.offset += o;
@@ -462,24 +462,16 @@ impl<'a> IndexingCodeMergingPtr<'a> {
 pub fn merge_clause_index(
     target_indexing_code: &mut Vec<IndexingLine>,
     skeleton: &mut [ClauseIndexInfo], // the clause to be merged is the last element in the skeleton.
-    new_clause_loc: usize, // the absolute location of the new clause in the code vector.
+    new_clause_loc: usize,            // the absolute location of the new clause in the code vector.
     append_or_prepend: AppendOrPrepend,
 ) {
-    let opt_arg_index_key =
+    let opt_arg_index_key = match append_or_prepend {
-        match append_or_prepend {
+        AppendOrPrepend::Append => skeleton.last_mut().unwrap().opt_arg_index_key.take(),
-            AppendOrPrepend::Append => {
+        AppendOrPrepend::Prepend => skeleton.first_mut().unwrap().opt_arg_index_key.take(),
-                skeleton.last_mut().unwrap().opt_arg_index_key.take()
+    };
-            }
-            AppendOrPrepend::Prepend => {
-                skeleton.first_mut().unwrap().opt_arg_index_key.take()
-            }
-        };
 
-    let mut merging_ptr = IndexingCodeMergingPtr::new(
+    let mut merging_ptr =
-        skeleton,
+        IndexingCodeMergingPtr::new(skeleton, target_indexing_code, append_or_prepend);
-        target_indexing_code,
-        append_or_prepend,
-    );
 
     match &opt_arg_index_key {
         OptArgIndexKey::Constant(_, index_loc, ref constant, ref overlapping_constants) => {
@@ -488,7 +480,9 @@ pub fn merge_clause_index(
 
             for overlapping_constant in overlapping_constants {
                 merging_ptr.index_overlapping_constant(
-                    constant, overlapping_constant.clone(), offset,
+                    constant,
+                    overlapping_constant.clone(),
+                    offset,
                 );
             }
         }
@@ -514,10 +508,7 @@ pub fn merge_clause_index(
 }
 
 #[inline]
-fn remove_instruction_with_offset(
+fn remove_instruction_with_offset(code: &mut SliceDeque<IndexedChoiceInstruction>, offset: usize) {
-    code: &mut SliceDeque<IndexedChoiceInstruction>,
-    offset: usize,
-) {
     for (index, line) in code.iter().enumerate() {
         if offset == line.offset() {
             code.remove(index);
@@ -537,9 +528,7 @@ pub fn remove_constant_indices(
     let iter = once(constant).chain(overlapping_constants.iter());
 
     match &mut indexing_code[index] {
-        IndexingLine::Indexing(
+        IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)) => {
-            IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)
-        ) => {
             match *c {
                 IndexingCodePtr::External(_) => {
                     *c = IndexingCodePtr::Fail;
@@ -560,12 +549,13 @@ pub fn remove_constant_indices(
 
     let mut constants_index = 0;
 
-    for constant in iter { // (constant, index_loc) in iter.zip(index_locs.iter()) {
+    for constant in iter {
+        // (constant, index_loc) in iter.zip(index_locs.iter()) {
         loop {
             match &mut indexing_code[index] {
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnConstant(
-                    IndexingInstruction::SwitchOnConstant(ref mut constants)
+                    ref mut constants,
-                ) => {
+                )) => {
                     constants_index = index;
 
                     match constants.get(constant).cloned() {
@@ -586,18 +576,21 @@ pub fn remove_constant_indices(
 
                     if indexed_choice_instrs.len() == 1 {
                         let ext = IndexingCodePtr::External(
-                            indexed_choice_instrs.pop_back().unwrap().offset()
+                            indexed_choice_instrs.pop_back().unwrap().offset(),
                         );
 
                         match &mut indexing_code[constants_index] {
-                            IndexingLine::Indexing(
+                            IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(
-                                IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)
+                                _,
-                            ) => {
+                                _,
+                                ref mut c,
+                                ..,
+                            )) => {
                                 *c = ext;
                             }
-                            IndexingLine::Indexing(
+                            IndexingLine::Indexing(IndexingInstruction::SwitchOnConstant(
-                                IndexingInstruction::SwitchOnConstant(ref mut constants)
+                                ref mut constants,
-                            ) => {
+                            )) => {
                                 constants.insert(constant.clone(), ext);
                             }
                             _ => {
@@ -616,13 +609,11 @@ pub fn remove_constant_indices(
     }
 
     match &indexing_code[constants_index] {
-        IndexingLine::Indexing(
+        IndexingLine::Indexing(IndexingInstruction::SwitchOnConstant(ref constants))
-            IndexingInstruction::SwitchOnConstant(ref constants)
+            if constants.is_empty() =>
-        ) if constants.is_empty() => {
+        {
             match &mut indexing_code[0] {
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)) => {
-                    IndexingInstruction::SwitchOnTerm(_, _, ref mut c, ..)
-                ) => {
                     *c = IndexingCodePtr::Fail;
                 }
                 _ => {
@@ -630,8 +621,7 @@ pub fn remove_constant_indices(
                 }
             }
         }
-        _ => {
+        _ => {}
-        }
     }
 }
 
@@ -644,9 +634,7 @@ pub fn remove_structure_index(
     let mut index = 0;
 
     match &mut indexing_code[index] {
-        IndexingLine::Indexing(
+        IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(_, _, _, _, ref mut s)) => {
-            IndexingInstruction::SwitchOnTerm(_, _, _, _, ref mut s)
-        ) => {
             match *s {
                 IndexingCodePtr::External(_) => {
                     *s = IndexingCodePtr::Fail;
@@ -669,9 +657,7 @@ pub fn remove_structure_index(
 
     loop {
         match &mut indexing_code[index] {
-            IndexingLine::Indexing(
+            IndexingLine::Indexing(IndexingInstruction::SwitchOnStructure(ref mut structures)) => {
-                IndexingInstruction::SwitchOnStructure(ref mut structures)
-            ) => {
                 structures_index = index;
 
                 match structures.get(&(name.clone(), arity)).cloned() {
@@ -692,18 +678,22 @@ pub fn remove_structure_index(
 
                 if indexed_choice_instrs.len() == 1 {
                     let ext = IndexingCodePtr::External(
-                        indexed_choice_instrs.pop_back().unwrap().offset()
+                        indexed_choice_instrs.pop_back().unwrap().offset(),
                     );
 
                     match &mut indexing_code[structures_index] {
-                        IndexingLine::Indexing(
+                        IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(
-                            IndexingInstruction::SwitchOnTerm(_, _, _, _, ref mut s)
+                            _,
-                        ) => {
+                            _,
+                            _,
+                            _,
+                            ref mut s,
+                        )) => {
                             *s = ext;
                         }
-                        IndexingLine::Indexing(
+                        IndexingLine::Indexing(IndexingInstruction::SwitchOnStructure(
-                            IndexingInstruction::SwitchOnStructure(ref mut structures)
+                            ref mut structures,
-                        ) => {
+                        )) => {
                             structures.insert((name.clone(), arity), ext);
                         }
                         _ => {
@@ -721,13 +711,17 @@ pub fn remove_structure_index(
     }
 
     match &indexing_code[structures_index] {
-        IndexingLine::Indexing(
+        IndexingLine::Indexing(IndexingInstruction::SwitchOnStructure(ref structures))
-            IndexingInstruction::SwitchOnStructure(ref structures)
+            if structures.is_empty() =>
-        ) if structures.is_empty() => {
+        {
             match &mut indexing_code[0] {
-                IndexingLine::Indexing(
+                IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(
-                    IndexingInstruction::SwitchOnTerm(_, _, _, _, ref mut s)
+                    _,
-                ) => {
+                    _,
+                    _,
+                    _,
+                    ref mut s,
+                )) => {
                     *s = IndexingCodePtr::Fail;
                 }
                 _ => {
@@ -735,21 +729,15 @@ pub fn remove_structure_index(
                 }
             }
         }
-        _ => {
+        _ => {}
-        }
     }
 }
 
-pub fn remove_list_index(
+pub fn remove_list_index(indexing_code: &mut Vec<IndexingLine>, offset: usize) {
-    indexing_code: &mut Vec<IndexingLine>,
-    offset: usize,
-) {
     let mut index = 0;
 
     match &mut indexing_code[index] {
-        IndexingLine::Indexing(
+        IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(_, _, _, ref mut l, _)) => {
-            IndexingInstruction::SwitchOnTerm(_, _, _, ref mut l, _)
-        ) => {
             match *l {
                 IndexingCodePtr::External(_) => {
                     *l = IndexingCodePtr::Fail;
@@ -773,14 +761,17 @@ pub fn remove_list_index(
             remove_instruction_with_offset(indexed_choice_instrs, offset);
 
             if indexed_choice_instrs.len() == 1 {
-                let ext = IndexingCodePtr::External(
+                let ext =
-                    indexed_choice_instrs.pop_back().unwrap().offset()
+                    IndexingCodePtr::External(indexed_choice_instrs.pop_back().unwrap().offset());
-                );
 
                 match &mut indexing_code[0] {
-                    IndexingLine::Indexing(
+                    IndexingLine::Indexing(IndexingInstruction::SwitchOnTerm(
-                        IndexingInstruction::SwitchOnTerm(_, _, _, ref mut l, _)
+                        _,
-                    ) => {
+                        _,
+                        _,
+                        ref mut l,
+                        _,
+                    )) => {
                         *l = ext;
                     }
                     _ => {
@@ -836,8 +827,7 @@ pub fn remove_index(
 fn second_level_index<IndexKey: Eq + Hash>(
     indices: IndexMap<IndexKey, SliceDeque<IndexedChoiceInstruction>>,
     prelude: &mut SliceDeque<IndexingLine>,
-) -> IndexMap<IndexKey, IndexingCodePtr>
+) -> IndexMap<IndexKey, IndexingCodePtr> {
-{
     let mut index_locs = IndexMap::new();
 
     for (key, mut code) in indices.into_iter() {
@@ -868,10 +858,11 @@ fn switch_on<IndexKey: Eq + Hash>(
 
         IndexingCodePtr::Internal(1)
     } else {
-        index.into_iter()
+        index
-             .next()
+            .into_iter()
-             .map(|(_, v)| v)
+            .next()
-             .unwrap_or(IndexingCodePtr::Fail)
+            .map(|(_, v)| v)
+            .unwrap_or(IndexingCodePtr::Fail)
     }
 }
 
@@ -884,9 +875,10 @@ fn switch_on_list(
         prelude.push_back(IndexingLine::from(lists));
         IndexingCodePtr::Internal(1)
     } else {
-        lists.first()
+        lists
-             .map(|i| IndexingCodePtr::External(i.offset()))
+            .first()
-             .unwrap_or(IndexingCodePtr::Fail)
+            .map(|i| IndexingCodePtr::External(i.offset()))
+            .unwrap_or(IndexingCodePtr::Fail)
     }
 }
 
@@ -978,8 +970,7 @@ pub fn constant_key_alternatives(constant: &Constant, atom_tbl: TabledData<Atom>
                 constants.push(Constant::Fixnum(n));
             }
         }
-        _ => {
+        _ => {}
-        }
     }
 
     constants
@@ -1001,7 +992,7 @@ impl CodeOffsets {
             constants: IndexMap::new(),
             lists: sdeq![],
             structures: IndexMap::new(),
-            optimal_index
+            optimal_index,
         }
     }
 
@@ -1011,20 +1002,15 @@ impl CodeOffsets {
     }
 
     fn index_constant(&mut self, constant: &Constant, index: usize) -> Vec<Constant> {
-        let overlapping_constants =
+        let overlapping_constants = constant_key_alternatives(constant, self.atom_tbl.clone());
-            constant_key_alternatives(constant, self.atom_tbl.clone());
 
-        let code = self.constants
+        let code = self.constants.entry(constant.clone()).or_insert(sdeq![]);
-            .entry(constant.clone())
-            .or_insert(sdeq![]);
 
         let is_initial_index = code.is_empty();
         code.push_back(compute_index(is_initial_index, index));
 
         for constant in &overlapping_constants {
-            let code = self.constants
+            let code = self.constants.entry(constant.clone()).or_insert(sdeq![]);
-                .entry(constant.clone())
-                .or_insert(sdeq![]);
 
             let is_initial_index = code.is_empty();
             let index = compute_index(is_initial_index, index);
@@ -1062,25 +1048,21 @@ impl CodeOffsets {
                 self.index_structure(name, terms.len(), index);
             }
             &Term::Cons(..) | &Term::Constant(_, Constant::String(_)) => {
-                clause_index_info.opt_arg_index_key =
+                clause_index_info.opt_arg_index_key = OptArgIndexKey::List(self.optimal_index, 0);
-                    OptArgIndexKey::List(self.optimal_index, 0);
 
                 self.index_list(index);
             }
             &Term::Constant(_, ref constant) => {
-                let overlapping_constants =
+                let overlapping_constants = self.index_constant(constant, index);
-                    self.index_constant(constant, index);
 
-                clause_index_info.opt_arg_index_key =
+                clause_index_info.opt_arg_index_key = OptArgIndexKey::Constant(
-                    OptArgIndexKey::Constant(
+                    self.optimal_index,
-                        self.optimal_index,
+                    0,
-                        0,
+                    constant.clone(),
-                        constant.clone(),
+                    overlapping_constants,
-                        overlapping_constants,
+                );
-                    );
-            }
-            _ => {
             }
+            _ => {}
         }
     }
 
@@ -1117,8 +1099,7 @@ impl CodeOffsets {
             IndexingCodePtr::Internal(ref mut i) => {
                 *i += con_loc.is_internal() as usize;
             }
-            _ => {
+            _ => {}
-            }
         };
 
         match &mut lst_loc {
@@ -1126,15 +1107,18 @@ impl CodeOffsets {
                 *i += con_loc.is_internal() as usize;
                 *i += str_loc.is_internal() as usize;
             }
-            _ => {
+            _ => {}
-            }
         };
 
         let var_offset = 1 + skip_stub_try_me_else as usize;
 
-        prelude.push_front(IndexingLine::from(
+        prelude.push_front(IndexingLine::from(IndexingInstruction::SwitchOnTerm(
-            IndexingInstruction::SwitchOnTerm(self.optimal_index, var_offset, con_loc, lst_loc, str_loc)
+            self.optimal_index,
-        ));
+            var_offset,
+            con_loc,
+            lst_loc,
+            str_loc,
+        )));
 
         prelude.into_iter().collect()
     }

src/instructions.rs

@@ -1,4 +1,5 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::clause_name;
 
 use crate::clause_types::*;
 use crate::forms::*;
@@ -34,9 +35,7 @@ impl Level {
 impl ArithmeticTerm {
     fn into_functor(&self) -> MachineStub {
         match self {
-            &ArithmeticTerm::Reg(r) => {
+            &ArithmeticTerm::Reg(r) => reg_type_into_functor(r),
-                reg_type_into_functor(r)
-            }
             &ArithmeticTerm::Interm(i) => {
                 functor!("intermediate", [integer(i)])
             }
@@ -185,16 +184,11 @@ impl Line {
 
     pub fn enqueue_functors(&self, mut h: usize, functors: &mut Vec<MachineStub>) {
         match self {
-            &Line::Arithmetic(ref arith_instr) =>
+            &Line::Arithmetic(ref arith_instr) => functors.push(arith_instr.to_functor(h)),
-                functors.push(arith_instr.to_functor(h)),
+            &Line::Choice(ref choice_instr) => functors.push(choice_instr.to_functor()),
-            &Line::Choice(ref choice_instr) =>
+            &Line::Control(ref control_instr) => functors.push(control_instr.to_functor()),
-                functors.push(choice_instr.to_functor()),
+            &Line::Cut(ref cut_instr) => functors.push(cut_instr.to_functor(h)),
-            &Line::Control(ref control_instr) =>
+            &Line::Fact(ref fact_instr) => functors.push(fact_instr.to_functor(h)),
-                functors.push(control_instr.to_functor()),
-            &Line::Cut(ref cut_instr) =>
-                functors.push(cut_instr.to_functor(h)),
-            &Line::Fact(ref fact_instr) =>
-                functors.push(fact_instr.to_functor(h)),
             &Line::IndexingCode(ref indexing_instrs) => {
                 for indexing_instr in indexing_instrs {
                     match indexing_instr {
@@ -213,10 +207,10 @@ impl Line {
                     }
                 }
             }
-            &Line::IndexedChoice(ref indexed_choice_instr) =>
+            &Line::IndexedChoice(ref indexed_choice_instr) => {
-                functors.push(indexed_choice_instr.to_functor()),
+                functors.push(indexed_choice_instr.to_functor())
-            &Line::Query(ref query_instr) =>
+            }
-                functors.push(query_instr.to_functor(h)),
+            &Line::Query(ref query_instr) => functors.push(query_instr.to_functor(h)),
         }
     }
 }
@@ -224,24 +218,16 @@ impl Line {
 #[inline]
 pub fn to_indexing_line_mut(line: &mut Line) -> Option<&mut Vec<IndexingLine>> {
     match line {
-        Line::IndexingCode(ref mut indexing_code) => {
+        Line::IndexingCode(ref mut indexing_code) => Some(indexing_code),
-            Some(indexing_code)
+        _ => None,
-        }
-        _ => {
-            None
-        }
     }
 }
 
 #[inline]
 pub fn to_indexing_line(line: &Line) -> Option<&Vec<IndexingLine>> {
     match line {
-        Line::IndexingCode(ref indexing_code) => {
+        Line::IndexingCode(ref indexing_code) => Some(indexing_code),
-            Some(indexing_code)
+        _ => None,
-        }
-        _ => {
-            None
-        }
     }
 }
 
@@ -296,11 +282,7 @@ fn arith_instr_unary_functor(
 ) -> MachineStub {
     let at_stub = at.into_functor();
 
-    functor!(
+    functor!(name, [aux(h, 0), integer(t)], [at_stub])
-        name,
-        [aux(h, 0), integer(t)],
-        [at_stub]
-    )
 }
 
 fn arith_instr_bin_functor(
@@ -383,39 +365,17 @@ impl ArithmeticInstruction {
             &ArithmeticInstruction::Gcd(ref at_1, ref at_2, t) => {
                 arith_instr_bin_functor(h, "gcd", at_1, at_2, t)
             }
-            &ArithmeticInstruction::Sign(ref at, t) => {
+            &ArithmeticInstruction::Sign(ref at, t) => arith_instr_unary_functor(h, "sign", at, t),
-                arith_instr_unary_functor(h, "sign", at, t)
+            &ArithmeticInstruction::Cos(ref at, t) => arith_instr_unary_functor(h, "cos", at, t),
-            }
+            &ArithmeticInstruction::Sin(ref at, t) => arith_instr_unary_functor(h, "sin", at, t),
-            &ArithmeticInstruction::Cos(ref at, t)  => {
+            &ArithmeticInstruction::Tan(ref at, t) => arith_instr_unary_functor(h, "tan", at, t),
-                arith_instr_unary_functor(h, "cos", at, t)
+            &ArithmeticInstruction::Log(ref at, t) => arith_instr_unary_functor(h, "log", at, t),
-            }
+            &ArithmeticInstruction::Exp(ref at, t) => arith_instr_unary_functor(h, "exp", at, t),
-            &ArithmeticInstruction::Sin(ref at, t)  => {
+            &ArithmeticInstruction::ACos(ref at, t) => arith_instr_unary_functor(h, "acos", at, t),
-                arith_instr_unary_functor(h, "sin", at, t)
+            &ArithmeticInstruction::ASin(ref at, t) => arith_instr_unary_functor(h, "asin", at, t),
-            }
+            &ArithmeticInstruction::ATan(ref at, t) => arith_instr_unary_functor(h, "atan", at, t),
-            &ArithmeticInstruction::Tan(ref at, t)  => {
+            &ArithmeticInstruction::Sqrt(ref at, t) => arith_instr_unary_functor(h, "sqrt", at, t),
-                arith_instr_unary_functor(h, "tan", at, t)
+            &ArithmeticInstruction::Abs(ref at, t) => arith_instr_unary_functor(h, "abs", at, t),
-            }
-            &ArithmeticInstruction::Log(ref at, t)  => {
-                arith_instr_unary_functor(h, "log", at, t)
-            }
-            &ArithmeticInstruction::Exp(ref at, t)  => {
-                arith_instr_unary_functor(h, "exp", at, t)
-            }
-            &ArithmeticInstruction::ACos(ref at, t) => {
-                arith_instr_unary_functor(h, "acos", at, t)
-            }
-            &ArithmeticInstruction::ASin(ref at, t) => {
-                arith_instr_unary_functor(h, "asin", at, t)
-            }
-            &ArithmeticInstruction::ATan(ref at, t) => {
-                arith_instr_unary_functor(h, "atan", at, t)
-            }
-            &ArithmeticInstruction::Sqrt(ref at, t) => {
-                arith_instr_unary_functor(h, "sqrt", at, t)
-            }
-            &ArithmeticInstruction::Abs(ref at, t) => {
-                arith_instr_unary_functor(h, "abs", at, t)
-            }
             &ArithmeticInstruction::Float(ref at, t) => {
                 arith_instr_unary_functor(h, "float", at, t)
             }
@@ -431,12 +391,8 @@ impl ArithmeticInstruction {
             &ArithmeticInstruction::Floor(ref at, t) => {
                 arith_instr_unary_functor(h, "floor", at, t)
             }
-            &ArithmeticInstruction::Neg(ref at, t) => {
+            &ArithmeticInstruction::Neg(ref at, t) => arith_instr_unary_functor(h, "-", at, t),
-                arith_instr_unary_functor(h, "-", at, t)
+            &ArithmeticInstruction::Plus(ref at, t) => arith_instr_unary_functor(h, "+", at, t),
-            }
-            &ArithmeticInstruction::Plus(ref at, t) => {
-                arith_instr_unary_functor(h, "+", at, t)
-            }
             &ArithmeticInstruction::BitwiseComplement(ref at, t) => {
                 arith_instr_unary_functor(h, "\\", at, t)
             }
@@ -451,21 +407,18 @@ pub enum ControlInstruction {
     CallClause(ClauseType, usize, usize, bool, bool),
     Deallocate,
     JmpBy(usize, usize, usize, bool), // arity, global_offset, perm_vars after threshold, last call.
-    RevJmpBy(usize), // notice the lack of context change as in
+    RevJmpBy(usize),                  // notice the lack of context change as in
-                     // JmpBy. RevJmpBy is used only to patch extensible
+    // JmpBy. RevJmpBy is used only to patch extensible
-                     // predicates together.
+    // predicates together.
     Proceed,
 }
 
 impl ControlInstruction {
     pub fn perm_vars(&self) -> Option<usize> {
         match self {
-            ControlInstruction::CallClause(_, _, num_cells, ..) =>
+            ControlInstruction::CallClause(_, _, num_cells, ..) => Some(*num_cells),
-                Some(*num_cells),
+            ControlInstruction::JmpBy(_, _, num_cells, ..) => Some(*num_cells),
-            ControlInstruction::JmpBy(_, _, num_cells, ..) =>
+            _ => None,
-                Some(*num_cells),
-            _ =>
-                None
         }
     }
 
@@ -500,7 +453,13 @@ impl ControlInstruction {
 #[derive(Debug)]
 pub enum IndexingInstruction {
     // The first index is the optimal argument being indexed.
-    SwitchOnTerm(usize, usize, IndexingCodePtr, IndexingCodePtr, IndexingCodePtr),
+    SwitchOnTerm(
+        usize,
+        usize,
+        IndexingCodePtr,
+        IndexingCodePtr,
+        IndexingCodePtr,
+    ),
     SwitchOnConstant(IndexMap<Constant, IndexingCodePtr>),
     SwitchOnStructure(IndexMap<(ClauseName, usize), IndexingCodePtr>),
 }
@@ -511,11 +470,13 @@ impl IndexingInstruction {
             &IndexingInstruction::SwitchOnTerm(arg, vars, constants, lists, structures) => {
                 functor!(
                     "switch_on_term",
-                    [integer(arg),
+                    [
-                     integer(vars),
+                        integer(arg),
-                     indexing_code_ptr(h, constants),
+                        integer(vars),
-                     indexing_code_ptr(h, lists),
+                        indexing_code_ptr(h, constants),
-                     indexing_code_ptr(h, structures)]
+                        indexing_code_ptr(h, lists),
+                        indexing_code_ptr(h, structures)
+                    ]
                 )
             }
             &IndexingInstruction::SwitchOnConstant(ref constants) => {
@@ -528,15 +489,14 @@ impl IndexingInstruction {
                     let key_value_pair = functor!(
                         ":",
                         SharedOpDesc::new(600, XFY),
-                        [constant(c),
+                        [constant(c), indexing_code_ptr(h + 3, *ptr)]
-                         indexing_code_ptr(h + 3, *ptr)]
                     );
 
                     key_value_list_stub.push(HeapCellValue::Addr(Addr::Lis(h + 1)));
                     key_value_list_stub.push(HeapCellValue::Addr(Addr::Str(h + 3)));
-                    key_value_list_stub.push(HeapCellValue::Addr(
+                    key_value_list_stub.push(HeapCellValue::Addr(Addr::HeapCell(
-                        Addr::HeapCell(h + 3 + key_value_pair.len())
+                        h + 3 + key_value_pair.len(),
-                    ));
+                    )));
 
                     h += key_value_pair.len() + 3;
                     key_value_list_stub.extend(key_value_pair.into_iter());
@@ -560,23 +520,21 @@ impl IndexingInstruction {
                     let predicate_indicator_stub = functor!(
                         "/",
                         SharedOpDesc::new(400, YFX),
-                        [clause_name(name.clone()),
+                        [clause_name(name.clone()), integer(*arity)]
-                         integer(*arity)]
                     );
 
                     let key_value_pair = functor!(
                         ":",
                         SharedOpDesc::new(600, XFY),
-                        [aux(h + 3, 0),
+                        [aux(h + 3, 0), indexing_code_ptr(h + 3, *ptr)],
-                         indexing_code_ptr(h + 3, *ptr)],
                         [predicate_indicator_stub]
                     );
 
                     key_value_list_stub.push(HeapCellValue::Addr(Addr::Lis(h + 1)));
                     key_value_list_stub.push(HeapCellValue::Addr(Addr::Str(h + 3)));
-                    key_value_list_stub.push(HeapCellValue::Addr(
+                    key_value_list_stub.push(HeapCellValue::Addr(Addr::HeapCell(
-                        Addr::HeapCell(h + 3 + key_value_pair.len())
+                        h + 3 + key_value_pair.len(),
-                    ));
+                    )));
 
                     h += key_value_pair.len() + 3;
                     key_value_list_stub.extend(key_value_pair.into_iter());
@@ -614,7 +572,7 @@ impl FactInstruction {
         match self {
             &FactInstruction::GetConstant(lvl, ref c, r) => {
                 let lvl_stub = lvl.into_functor();
-                let rt_stub  = reg_type_into_functor(r);
+                let rt_stub = reg_type_into_functor(r);
 
                 functor!(
                     "get_constant",
@@ -624,17 +582,13 @@ impl FactInstruction {
             }
             &FactInstruction::GetList(lvl, r) => {
                 let lvl_stub = lvl.into_functor();
-                let rt_stub  = reg_type_into_functor(r);
+                let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("get_list", [aux(h, 0), aux(h, 1)], [lvl_stub, rt_stub])
-                    "get_list",
-                    [aux(h, 0), aux(h, 1)],
-                    [lvl_stub, rt_stub]
-                )
             }
             &FactInstruction::GetPartialString(lvl, ref s, r, has_tail) => {
                 let lvl_stub = lvl.into_functor();
-                let rt_stub  = reg_type_into_functor(r);
+                let rt_stub = reg_type_into_functor(r);
 
                 functor!(
                     "get_partial_string",
@@ -654,20 +608,12 @@ impl FactInstruction {
             &FactInstruction::GetValue(r, arg) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("get_value", [aux(h, 0), integer(arg)], [rt_stub])
-                    "get_value",
-                    [aux(h, 0), integer(arg)],
-                    [rt_stub]
-                )
             }
             &FactInstruction::GetVariable(r, arg) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("get_variable", [aux(h, 0), integer(arg)], [rt_stub])
-                    "get_variable",
-                    [aux(h, 0), integer(arg)],
-                    [rt_stub]
-                )
             }
             &FactInstruction::UnifyConstant(ref c) => {
                 functor!("unify_constant", [constant(h, c)], [])
@@ -675,29 +621,17 @@ impl FactInstruction {
             &FactInstruction::UnifyLocalValue(r) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("unify_local_value", [aux(h, 0)], [rt_stub])
-                    "unify_local_value",
-                    [aux(h, 0)],
-                    [rt_stub]
-                )
             }
             &FactInstruction::UnifyVariable(r) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("unify_variable", [aux(h, 0)], [rt_stub])
-                    "unify_variable",
-                    [aux(h, 0)],
-                    [rt_stub]
-                )
             }
             &FactInstruction::UnifyValue(r) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("unify_value", [aux(h, 0)], [rt_stub])
-                    "unify_value",
-                    [aux(h, 0)],
-                    [rt_stub]
-                )
             }
             &FactInstruction::UnifyVoid(vars) => {
                 functor!("unify_void", [integer(vars)])
@@ -726,13 +660,12 @@ pub enum QueryInstruction {
 impl QueryInstruction {
     pub fn to_functor(&self, h: usize) -> MachineStub {
         match self {
-            &QueryInstruction::PutUnsafeValue(norm, arg) => functor!(
+            &QueryInstruction::PutUnsafeValue(norm, arg) => {
-                "put_unsafe_value",
+                functor!("put_unsafe_value", [integer(norm), integer(arg)])
-                [integer(norm), integer(arg)]
+            }
-            ),
             &QueryInstruction::PutConstant(lvl, ref c, r) => {
                 let lvl_stub = lvl.into_functor();
-                let rt_stub  = reg_type_into_functor(r);
+                let rt_stub = reg_type_into_functor(r);
 
                 functor!(
                     "put_constant",
@@ -742,17 +675,13 @@ impl QueryInstruction {
             }
             &QueryInstruction::PutList(lvl, r) => {
                 let lvl_stub = lvl.into_functor();
-                let rt_stub  = reg_type_into_functor(r);
+                let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("put_list", [aux(h, 0), aux(h, 1)], [lvl_stub, rt_stub])
-                    "put_list",
-                    [aux(h, 0), aux(h, 1)],
-                    [lvl_stub, rt_stub]
-                )
             }
             &QueryInstruction::PutPartialString(lvl, ref s, r, has_tail) => {
                 let lvl_stub = lvl.into_functor();
-                let rt_stub  = reg_type_into_functor(r);
+                let rt_stub = reg_type_into_functor(r);
 
                 functor!(
                     "put_partial_string",
@@ -772,29 +701,17 @@ impl QueryInstruction {
             &QueryInstruction::PutValue(r, arg) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("put_value", [aux(h, 0), integer(arg)], [rt_stub])
-                    "put_value",
-                    [aux(h, 0), integer(arg)],
-                    [rt_stub]
-                )
             }
             &QueryInstruction::GetVariable(r, arg) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("get_variable", [aux(h, 0), integer(arg)], [rt_stub])
-                    "get_variable",
-                    [aux(h, 0), integer(arg)],
-                    [rt_stub]
-                )
             }
             &QueryInstruction::PutVariable(r, arg) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("put_variable", [aux(h, 0), integer(arg)], [rt_stub])
-                    "put_variable",
-                    [aux(h, 0), integer(arg)],
-                    [rt_stub]
-                )
             }
             &QueryInstruction::SetConstant(ref c) => {
                 functor!("set_constant", [constant(h, c)], [])
@@ -802,29 +719,17 @@ impl QueryInstruction {
             &QueryInstruction::SetLocalValue(r) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("set_local_value", [aux(h, 0)], [rt_stub])
-                    "set_local_value",
-                    [aux(h, 0)],
-                    [rt_stub]
-                )
             }
             &QueryInstruction::SetVariable(r) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("set_variable", [aux(h, 0)], [rt_stub])
-                    "set_variable",
-                    [aux(h, 0)],
-                    [rt_stub]
-                )
             }
             &QueryInstruction::SetValue(r) => {
                 let rt_stub = reg_type_into_functor(r);
 
-                functor!(
+                functor!("set_value", [aux(h, 0)], [rt_stub])
-                    "set_value",
-                    [aux(h, 0)],
-                    [rt_stub]
-                )
             }
             &QueryInstruction::SetVoid(vars) => {
                 functor!("set_void", [integer(vars)])

src/iterators.rs

@@ -1,4 +1,5 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::rc_atom;
 
 use crate::clause_types::*;
 use crate::forms::*;
@@ -25,11 +26,11 @@ impl<'a> TermRef<'a> {
     pub fn level(self) -> Level {
         match self {
             TermRef::AnonVar(lvl)
-          | TermRef::Cons(lvl, ..)
+            | TermRef::Cons(lvl, ..)
-          | TermRef::Constant(lvl, ..)
+            | TermRef::Constant(lvl, ..)
-          | TermRef::Var(lvl, ..)
+            | TermRef::Var(lvl, ..)
-          | TermRef::Clause(lvl, ..) => lvl,
+            | TermRef::Clause(lvl, ..) => lvl,
-          | TermRef::PartialString(lvl, ..) => lvl,
+            TermRef::PartialString(lvl, ..) => lvl,
         }
     }
 }
@@ -51,23 +52,16 @@ pub enum TermIterState<'a> {
     Var(Level, &'a Cell<VarReg>, Rc<Var>),
 }
 
-fn is_partial_string<'a>(
+fn is_partial_string<'a>(head: &'a Term, mut tail: &'a Term) -> Option<(String, Option<&'a Term>)> {
-    head: &'a Term,
+    let mut string = match head {
-    mut tail: &'a Term,
+        &Term::Constant(_, Constant::Atom(ref atom, _)) if atom.is_char() => {
-) -> Option<(String, Option<&'a Term>)>
+            atom.as_str().chars().next().unwrap().to_string()
-{
+        }
-    let mut string =
+        &Term::Constant(_, Constant::Char(c)) => c.to_string(),
-        match head {
+        _ => {
-            &Term::Constant(_, Constant::Atom(ref atom, _)) if atom.is_char() => {
+            return None;
-                atom.as_str().chars().next().unwrap().to_string()
+        }
-            }
+    };
-            &Term::Constant(_, Constant::Char(c)) => {
-                c.to_string()
-            }
-            _ => {
-                return None;
-            }
-        };
 
     while let Term::Cons(_, ref head, ref succ) = tail {
         match head.as_ref() {
@@ -105,9 +99,7 @@ fn is_partial_string<'a>(
 impl<'a> TermIterState<'a> {
     pub fn subterm_to_state(lvl: Level, term: &'a Term) -> TermIterState<'a> {
         match term {
-            &Term::AnonVar => {
+            &Term::AnonVar => TermIterState::AnonVar(lvl),
-                TermIterState::AnonVar(lvl)
-            }
             &Term::Clause(ref cell, ref name, ref subterms, ref spec) => {
                 let ct = if let Some(spec) = spec {
                     ClauseType::Op(name.clone(), spec.clone(), CodeIndex::default())
@@ -120,12 +112,8 @@ impl<'a> TermIterState<'a> {
             &Term::Cons(ref cell, ref head, ref tail) => {
                 TermIterState::InitialCons(lvl, cell, head.as_ref(), tail.as_ref())
             }
-            &Term::Constant(ref cell, ref constant) => {
+            &Term::Constant(ref cell, ref constant) => TermIterState::Constant(lvl, cell, constant),
-                TermIterState::Constant(lvl, cell, constant)
+            &Term::Var(ref cell, ref var) => TermIterState::Var(lvl, cell, var.clone()),
-            }
-            &Term::Var(ref cell, ref var) => {
-                TermIterState::Var(lvl, cell, var.clone())
-            }
         }
     }
 }
@@ -175,8 +163,7 @@ impl<'a> QueryIterator<'a> {
                     state_stack: vec![],
                 }
             }
-            &Term::Var(ref cell, ref var) =>
+            &Term::Var(ref cell, ref var) => TermIterState::Var(Level::Root, cell, (*var).clone()),
-                TermIterState::Var(Level::Root, cell, (*var).clone()),
         };
 
         QueryIterator {
@@ -265,18 +252,15 @@ impl<'a> Iterator for QueryIterator<'a> {
                 }
                 TermIterState::InitialCons(lvl, cell, head, tail) => {
                     if let Some((string, tail)) = is_partial_string(head, tail) {
-                        self.state_stack.push(TermIterState::PartialString(
+                        self.state_stack
-                            lvl,
+                            .push(TermIterState::PartialString(lvl, cell, string, tail));
-                            cell,
-                            string,
-                            tail,
-                        ));
 
                         if let Some(tail) = tail {
                             self.push_subterm(lvl.child_level(), tail);
                         }
                     } else {
-                        self.state_stack.push(TermIterState::FinalCons(lvl, cell, head, tail));
+                        self.state_stack
+                            .push(TermIterState::FinalCons(lvl, cell, head, tail));
 
                         self.push_subterm(lvl.child_level(), tail);
                         self.push_subterm(lvl.child_level(), head);
@@ -309,7 +293,8 @@ pub struct FactIterator<'a> {
 
 impl<'a> FactIterator<'a> {
     fn push_subterm(&mut self, lvl: Level, term: &'a Term) {
-        self.state_queue.push_back(TermIterState::subterm_to_state(lvl, term));
+        self.state_queue
+            .push_back(TermIterState::subterm_to_state(lvl, term));
     }
 
     pub fn from_rule_head_clause(terms: &'a Vec<Box<Term>>) -> Self {
@@ -393,8 +378,7 @@ impl<'a> Iterator for FactIterator<'a> {
                 TermIterState::Var(lvl, cell, var) => {
                     return Some(TermRef::Var(lvl, cell, var));
                 }
-                _ => {
+                _ => {}
-                }
             }
         }
 
@@ -481,16 +465,16 @@ impl<'a> ChunkedIterator<'a> {
             }
         }))
     }
-/*
+    /*
-    pub fn from_term_sequence(terms: &'a [QueryTerm]) -> Self {
+        pub fn from_term_sequence(terms: &'a [QueryTerm]) -> Self {
-        ChunkedIterator {
+            ChunkedIterator {
-            chunk_num: 0,
+                chunk_num: 0,
-            iter: Box::new(terms.iter().map(|t| ChunkedTerm::BodyTerm(t))),
+                iter: Box::new(terms.iter().map(|t| ChunkedTerm::BodyTerm(t))),
-            deep_cut_encountered: false,
+                deep_cut_encountered: false,
-            cut_var_in_head: false,
+                cut_var_in_head: false,
+            }
         }
-    }
+    */
-*/
     pub fn from_rule_body(p1: &'a QueryTerm, clauses: &'a Vec<QueryTerm>) -> Self {
         let inner_iter = Box::new(once(ChunkedTerm::BodyTerm(p1)));
         let iter = inner_iter.chain(clauses.iter().map(|t| ChunkedTerm::BodyTerm(t)));

src/machine/arithmetic_ops.rs

@@ -1,6 +1,7 @@
 use crate::divrem::*;
 
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::clause_name;
 
 use crate::arithmetic::*;
 use crate::clause_types::*;
@@ -19,19 +20,16 @@ use std::rc::Rc;
 
 #[macro_export]
 macro_rules! try_numeric_result {
-    ($s: ident, $e: expr, $caller: expr) => (
+    ($s: ident, $e: expr, $caller: expr) => {
         match $e {
-            Ok(val) => {
+            Ok(val) => Ok(val),
-                Ok(val)
-            }
             Err(e) => {
-                let caller_copy =
+                let caller_copy = $caller.iter().map(|v| v.context_free_clone()).collect();
-                    $caller.iter().map(|v| v.context_free_clone()).collect();
 
                 Err($s.error_form(MachineError::evaluation_error(e), caller_copy))
             }
         }
-    );
+    };
 }
 
 fn isize_gcd(n1: isize, n2: isize) -> Option<isize> {
@@ -83,52 +81,29 @@ fn isize_gcd(n1: isize, n2: isize) -> Option<isize> {
 }
 
 impl MachineState {
-    pub(crate)
+    pub(crate) fn get_number(&mut self, at: &ArithmeticTerm) -> Result<Number, MachineStub> {
-    fn get_number(&mut self, at: &ArithmeticTerm) -> Result<Number, MachineStub> {
         match at {
-            &ArithmeticTerm::Reg(r) => {
+            &ArithmeticTerm::Reg(r) => self.arith_eval_by_metacall(r),
-                self.arith_eval_by_metacall(r)
+            &ArithmeticTerm::Interm(i) => {
-            }
+                Ok(mem::replace(&mut self.interms[i - 1], Number::Fixnum(0)))
-            &ArithmeticTerm::Interm(i) => Ok(mem::replace(
-                &mut self.interms[i - 1],
-                Number::Fixnum(0),
-            )),
-            &ArithmeticTerm::Number(ref n) => {
-                Ok(n.clone())
             }
+            &ArithmeticTerm::Number(ref n) => Ok(n.clone()),
         }
     }
 
-    pub(super)
+    pub(super) fn rational_from_number(&self, n: Number) -> Result<Rc<Rational>, MachineError> {
-    fn rational_from_number(
-        &self,
-        n: Number,
-    ) -> Result<Rc<Rational>, MachineError> {
         match n {
-            Number::Fixnum(n) => {
+            Number::Fixnum(n) => Ok(Rc::new(Rational::from(n))),
-                Ok(Rc::new(Rational::from(n)))
+            Number::Rational(r) => Ok(r),
-            }
+            Number::Float(OrderedFloat(f)) => match Rational::from_f64(f) {
-            Number::Rational(r) => {
+                Some(r) => Ok(Rc::new(r)),
-                Ok(r)
+                None => Err(MachineError::instantiation_error()),
-            }
+            },
-            Number::Float(OrderedFloat(f)) => {
+            Number::Integer(n) => Ok(Rc::new(Rational::from(&*n))),
-                match Rational::from_f64(f) {
-                    Some(r) => {
-                        Ok(Rc::new(r))
-                    }
-                    None => {
-                        Err(MachineError::instantiation_error())
-                    }
-                }
-            }
-            Number::Integer(n) => {
-                Ok(Rc::new(Rational::from(&*n)))
-            }
         }
     }
 
-    pub(crate)
+    pub(crate) fn get_rational(
-    fn get_rational(
         &mut self,
         at: &ArithmeticTerm,
         caller: MachineStub,
@@ -137,12 +112,11 @@ impl MachineState {
 
         match self.rational_from_number(n) {
             Ok(r) => Ok((r, caller)),
-            Err(e) => Err(self.error_form(e, caller))
+            Err(e) => Err(self.error_form(e, caller)),
         }
     }
 
-    pub(crate)
+    pub(crate) fn arith_eval_by_metacall(&self, r: RegType) -> Result<Number, MachineStub> {
-    fn arith_eval_by_metacall(&self, r: RegType) -> Result<Number, MachineStub> {
         let caller = MachineError::functor_stub(clause_name!("is"), 2);
         let mut interms: Vec<Number> = Vec::with_capacity(64);
 
@@ -163,9 +137,8 @@ impl MachineState {
                         "min" => interms.push(self.min(a1, a2)?),
                         "rdiv" => {
                             let r1 = self.rational_from_number(a1);
-                            let r2 = r1.and_then(|r1| {
+                            let r2 =
-                                self.rational_from_number(a2).map(|r2| (r1, r2))
+                                r1.and_then(|r1| self.rational_from_number(a2).map(|r2| (r1, r2)));
-                            });
 
                             match r2 {
                                 Ok((r1, r2)) => {
@@ -242,18 +215,12 @@ impl MachineState {
                 &HeapCellValue::Addr(Addr::Fixnum(n)) => {
                     interms.push(Number::Fixnum(n));
                 }
-                &HeapCellValue::Addr(Addr::Float(n)) => {
+                &HeapCellValue::Addr(Addr::Float(n)) => interms.push(Number::Float(n)),
-                    interms.push(Number::Float(n))
+                &HeapCellValue::Integer(ref n) => interms.push(Number::Integer(n.clone())),
-                }
-                &HeapCellValue::Integer(ref n) => {
-                    interms.push(Number::Integer(n.clone()))
-                }
                 &HeapCellValue::Addr(Addr::Usize(n)) => {
                     interms.push(Number::Integer(Rc::new(Integer::from(n))));
                 }
-                &HeapCellValue::Rational(ref n) => {
+                &HeapCellValue::Rational(ref n) => interms.push(Number::Rational(n.clone())),
-                    interms.push(Number::Rational(n.clone()))
-                }
                 &HeapCellValue::Atom(ref name, _) if name.as_str() == "pi" => {
                     interms.push(Number::Float(OrderedFloat(f64::consts::PI)))
                 }
@@ -282,10 +249,7 @@ impl MachineState {
                     ));
                 }
                 &HeapCellValue::Addr(addr) if addr.is_ref() => {
-                    return Err(self.error_form(
+                    return Err(self.error_form(MachineError::instantiation_error(), caller));
-                        MachineError::instantiation_error(),
-                        caller,
-                    ));
                 }
                 val => {
                     return Err(self.type_error(
@@ -301,8 +265,7 @@ impl MachineState {
         Ok(interms.pop().unwrap())
     }
 
-    pub(crate)
+    pub(crate) fn rdiv(&self, r1: Rc<Rational>, r2: Rc<Rational>) -> Result<Rational, MachineStub> {
-    fn rdiv(&self, r1: Rc<Rational>, r2: Rc<Rational>) -> Result<Rational, MachineStub> {
         if &*r2 == &0 {
             let stub = MachineError::functor_stub(clause_name!("(rdiv)"), 2);
             Err(self.error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
@@ -311,27 +274,21 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn int_floor_div(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn int_floor_div(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(div)"), 2);
         let modulus = self.modulus(n1.clone(), n2.clone())?;
 
         self.idiv(try_numeric_result!(self, n1 - modulus, stub)?, n2)
     }
 
-    pub(crate)
+    pub(crate) fn idiv(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn idiv(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         match (n1, n2) {
             (Number::Fixnum(n1), Number::Fixnum(n2)) => {
                 if n2 == 0 {
                     let stub = MachineError::functor_stub(clause_name!("(//)"), 2);
 
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                            EvalError::ZeroDivisor
-                        ),
-                        stub,
-                    ))
                 } else {
                     if let Some(result) = n1.checked_div(n2) {
                         Ok(Number::from(result))
@@ -347,12 +304,8 @@ impl MachineState {
                 if &*n2 == &0 {
                     let stub = MachineError::functor_stub(clause_name!("(//)"), 2);
 
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                            EvalError::ZeroDivisor
-                        ),
-                        stub,
-                    ))
                 } else {
                     Ok(Number::from(Integer::from(n1) / &*n2))
                 }
@@ -361,12 +314,8 @@ impl MachineState {
                 if n1 == 0 {
                     let stub = MachineError::functor_stub(clause_name!("(//)"), 2);
 
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                            EvalError::ZeroDivisor
-                        ),
-                        stub,
-                    ))
                 } else {
                     Ok(Number::from(&*n2 / Integer::from(n1)))
                 }
@@ -375,25 +324,19 @@ impl MachineState {
                 if &*n2 == &0 {
                     let stub = MachineError::functor_stub(clause_name!("(//)"), 2);
 
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                            EvalError::ZeroDivisor
-                        ),
-                        stub,
-                    ))
                 } else {
-                    Ok(Number::from(<(Integer, Integer)>::from(n1.div_rem_ref(&*n2)).0))
+                    Ok(Number::from(
+                        <(Integer, Integer)>::from(n1.div_rem_ref(&*n2)).0,
+                    ))
                 }
             }
             (Number::Fixnum(_), n2) | (Number::Integer(_), n2) => {
                 let stub = MachineError::functor_stub(clause_name!("(//)"), 2);
 
                 Err(self.error_form(
-                    MachineError::type_error(
+                    MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
-                        self.heap.h(),
-                        ValidType::Integer,
-                        n2,
-                    ),
                     stub,
                 ))
             }
@@ -401,19 +344,14 @@ impl MachineState {
                 let stub = MachineError::functor_stub(clause_name!("(//)"), 2);
 
                 Err(self.error_form(
-                    MachineError::type_error(
+                    MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                        self.heap.h(),
-                        ValidType::Integer,
-                        n1,
-                    ),
                     stub,
                 ))
             }
         }
     }
 
-    pub(crate)
+    pub(crate) fn div(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn div(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(/)"), 2);
 
         if n2.is_zero() {
@@ -423,8 +361,7 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn atan2(&self, n1: Number, n2: Number) -> Result<f64, MachineStub> {
-    fn atan2(&self, n1: Number, n2: Number) -> Result<f64, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("is"), 2);
 
         if n1.is_zero() && n2.is_zero() {
@@ -437,8 +374,7 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn int_pow(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn int_pow(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         if n1.is_zero() && n2.is_negative() {
             let stub = MachineError::functor_stub(clause_name!("is"), 2);
             return Err(self.error_form(MachineError::evaluation_error(EvalError::Undefined), stub));
@@ -451,11 +387,7 @@ impl MachineState {
                     let stub = MachineError::functor_stub(clause_name!("^"), 2);
 
                     Err(self.error_form(
-                        MachineError::type_error(
+                        MachineError::type_error(self.heap.h(), ValidType::Float, n),
-                            self.heap.h(),
-                            ValidType::Float,
-                            n
-                        ),
                         stub,
                     ))
                 } else {
@@ -477,11 +409,7 @@ impl MachineState {
                     let stub = MachineError::functor_stub(clause_name!("^"), 2);
 
                     Err(self.error_form(
-                        MachineError::type_error(
+                        MachineError::type_error(self.heap.h(), ValidType::Float, n),
-                            self.heap.h(),
-                            ValidType::Float,
-                            n
-                        ),
                         stub,
                     ))
                 } else {
@@ -495,11 +423,7 @@ impl MachineState {
                     let stub = MachineError::functor_stub(clause_name!("^"), 2);
 
                     Err(self.error_form(
-                        MachineError::type_error(
+                        MachineError::type_error(self.heap.h(), ValidType::Float, n),
-                            self.heap.h(),
-                            ValidType::Float,
-                            n
-                        ),
                         stub,
                     ))
                 } else {
@@ -513,11 +437,7 @@ impl MachineState {
                     let stub = MachineError::functor_stub(clause_name!("^"), 2);
 
                     Err(self.error_form(
-                        MachineError::type_error(
+                        MachineError::type_error(self.heap.h(), ValidType::Float, n),
-                            self.heap.h(),
-                            ValidType::Float,
-                            n
-                        ),
                         stub,
                     ))
                 } else {
@@ -548,8 +468,7 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn gcd(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn gcd(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         match (n1, n2) {
             (Number::Fixnum(n1), Number::Fixnum(n2)) => {
                 if let Some(result) = isize_gcd(n1, n2) {
@@ -558,8 +477,8 @@ impl MachineState {
                     Ok(Number::from(Integer::from(n1).gcd(&Integer::from(n2))))
                 }
             }
-            (Number::Fixnum(n1), Number::Integer(n2)) |
+            (Number::Fixnum(n1), Number::Integer(n2))
-            (Number::Integer(n2), Number::Fixnum(n1)) => {
+            | (Number::Integer(n2), Number::Fixnum(n1)) => {
                 let n1 = Integer::from(n1);
                 Ok(Number::from(Integer::from(n2.gcd_ref(&n1))))
             }
@@ -571,11 +490,7 @@ impl MachineState {
                 let stub = MachineError::functor_stub(clause_name!("gcd"), 2);
 
                 Err(self.error_form(
-                    MachineError::type_error(
+                    MachineError::type_error(self.heap.h(), ValidType::Integer, n),
-                        self.heap.h(),
-                        ValidType::Integer,
-                        n
-                    ),
                     stub,
                 ))
             }
@@ -584,19 +499,14 @@ impl MachineState {
                 let stub = MachineError::functor_stub(clause_name!("gcd"), 2);
 
                 Err(self.error_form(
-                    MachineError::type_error(
+                    MachineError::type_error(self.heap.h(), ValidType::Integer, n),
-                        self.heap.h(),
-                        ValidType::Integer,
-                        n,
-                    ),
                     stub,
                 ))
             }
         }
     }
 
-    pub(crate)
+    pub(crate) fn float_pow(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn float_pow(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let f1 = result_f(&n1, rnd_f);
         let f2 = result_f(&n2, rnd_f);
 
@@ -612,8 +522,12 @@ impl MachineState {
         )?)))
     }
 
-    pub(crate)
+    pub(crate) fn pow(
-    fn pow(&self, n1: Number, n2: Number, culprit: &'static str) -> Result<Number, MachineStub> {
+        &self,
+        n1: Number,
+        n2: Number,
+        culprit: &'static str,
+    ) -> Result<Number, MachineStub> {
         if n2.is_negative() && n1.is_zero() {
             let stub = MachineError::functor_stub(clause_name!(culprit), 2);
             return Err(self.error_form(MachineError::evaluation_error(EvalError::Undefined), stub));
@@ -623,8 +537,11 @@ impl MachineState {
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn unary_float_fn_template<FloatFn>(
-    fn unary_float_fn_template<FloatFn>(&self, n1: Number, f: FloatFn) -> Result<f64, MachineStub>
+        &self,
+        n1: Number,
+        f: FloatFn,
+    ) -> Result<f64, MachineStub>
     where
         FloatFn: Fn(f64) -> f64,
     {
@@ -637,56 +554,47 @@ impl MachineState {
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn sin(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn sin(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.sin())
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn cos(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn cos(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.cos())
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn tan(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn tan(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.tan())
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn log(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn log(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.log(f64::consts::E))
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn exp(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn exp(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.exp())
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn asin(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn asin(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.asin())
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn acos(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn acos(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.acos())
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn atan(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn atan(&self, n1: Number) -> Result<f64, MachineStub> {
         self.unary_float_fn_template(n1, |f| f.atan())
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn sqrt(&self, n1: Number) -> Result<f64, MachineStub> {
-    fn sqrt(&self, n1: Number) -> Result<f64, MachineStub> {
         if n1.is_negative() {
             let stub = MachineError::functor_stub(clause_name!("is"), 2);
             return Err(self.error_form(MachineError::evaluation_error(EvalError::Undefined), stub));
@@ -696,27 +604,23 @@ impl MachineState {
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn float(&self, n: Number) -> Result<f64, MachineStub> {
-    fn float(&self, n: Number) -> Result<f64, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("is"), 2);
         try_numeric_result!(self, result_f(&n, rnd_f), stub)
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn floor(&self, n1: Number) -> Number {
-    fn floor(&self, n1: Number) -> Number {
         rnd_i(&n1).to_owned()
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn ceiling(&self, n1: Number) -> Number {
-    fn ceiling(&self, n1: Number) -> Number {
         -self.floor(-n1)
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn truncate(&self, n: Number) -> Number {
-    fn truncate(&self, n: Number) -> Number {
         if n.is_negative() {
             -self.floor(n.abs())
         } else {
@@ -724,8 +628,7 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn round(&self, n: Number) -> Result<Number, MachineStub> {
-    fn round(&self, n: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("is"), 2);
 
         let result = n + Number::Float(OrderedFloat(0.5f64));
@@ -734,8 +637,7 @@ impl MachineState {
         Ok(self.floor(result))
     }
 
-    pub(crate)
+    pub(crate) fn shr(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn shr(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(>>)"), 2);
 
         match (n1, n2) {
@@ -756,38 +658,26 @@ impl MachineState {
                     _ => Ok(Number::from(n1 >> u32::max_value())),
                 }
             }
-            (Number::Integer(n1), Number::Fixnum(n2)) => {
+            (Number::Integer(n1), Number::Fixnum(n2)) => match u32::try_from(n2) {
-                match u32::try_from(n2) {
+                Ok(n2) => Ok(Number::from(Integer::from(&*n1 >> n2))),
-                    Ok(n2) => Ok(Number::from(Integer::from(&*n1 >> n2))),
+                _ => Ok(Number::from(Integer::from(&*n1 >> u32::max_value()))),
-                    _ => Ok(Number::from(Integer::from(&*n1 >> u32::max_value()))),
+            },
-                }
+            (Number::Integer(n1), Number::Integer(n2)) => match n2.to_u32() {
-            }
+                Some(n2) => Ok(Number::from(Integer::from(&*n1 >> n2))),
-            (Number::Integer(n1), Number::Integer(n2)) =>
+                _ => Ok(Number::from(Integer::from(&*n1 >> u32::max_value()))),
-                match n2.to_u32() {
+            },
-                    Some(n2) => Ok(Number::from(Integer::from(&*n1 >> n2))),
-                    _ => Ok(Number::from(Integer::from(&*n1 >> u32::max_value()))),
-                },
             (Number::Integer(_), n2) => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n2,
-                ),
                 stub,
             )),
             (n1, _) => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n1,
-                ),
                 stub,
             )),
         }
     }
 
-    pub(crate)
+    pub(crate) fn shl(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn shl(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(<<)"), 2);
 
         match (n1, n2) {
@@ -808,263 +698,181 @@ impl MachineState {
                     _ => Ok(Number::from(n1 << u32::max_value())),
                 }
             }
-            (Number::Integer(n1), Number::Fixnum(n2)) => {
+            (Number::Integer(n1), Number::Fixnum(n2)) => match u32::try_from(n2) {
-                match u32::try_from(n2) {
+                Ok(n2) => Ok(Number::from(Integer::from(&*n1 << n2))),
-                    Ok(n2) => Ok(Number::from(Integer::from(&*n1 << n2))),
+                _ => Ok(Number::from(Integer::from(&*n1 << u32::max_value()))),
-                    _ => Ok(Number::from(Integer::from(&*n1 << u32::max_value()))),
+            },
-                }
-            }
             (Number::Integer(n1), Number::Integer(n2)) => match n2.to_u32() {
                 Some(n2) => Ok(Number::from(Integer::from(&*n1 << n2))),
                 _ => Ok(Number::from(Integer::from(&*n1 << u32::max_value()))),
             },
             (Number::Integer(_), n2) => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n2,
-                ),
                 stub,
             )),
             (n1, _) => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n1,
-                ),
                 stub,
             )),
         }
     }
 
-    pub(crate)
+    pub(crate) fn bitwise_complement(&self, n1: Number) -> Result<Number, MachineStub> {
-    fn bitwise_complement(&self, n1: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(\\)"), 2);
 
         match n1 {
             Number::Fixnum(n) => Ok(Number::Fixnum(!n)),
             Number::Integer(n1) => Ok(Number::from(Integer::from(!&*n1))),
             _ => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n1,
-                ),
                 stub,
             )),
         }
     }
 
-    pub(crate)
+    pub(crate) fn xor(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn xor(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(xor)"), 2);
 
         match (n1, n2) {
-            (Number::Fixnum(n1), Number::Fixnum(n2)) => {
+            (Number::Fixnum(n1), Number::Fixnum(n2)) => Ok(Number::from(n1 ^ n2)),
-                Ok(Number::from(n1 ^ n2))
-            }
             (Number::Fixnum(n1), Number::Integer(n2)) => {
                 let n1 = Integer::from(n1);
                 Ok(Number::from(n1 ^ &*n2))
             }
-            (Number::Integer(n1), Number::Fixnum(n2)) => {
+            (Number::Integer(n1), Number::Fixnum(n2)) => Ok(Number::from(&*n1 ^ Integer::from(n2))),
-                Ok(Number::from(&*n1 ^ Integer::from(n2)))
-            }
             (Number::Integer(n1), Number::Integer(n2)) => {
                 Ok(Number::from(Integer::from(&*n1 ^ &*n2)))
             }
-            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => {
+            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => Err(self.error_form(
-                Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
-                    MachineError::type_error(
+                stub,
-                        self.heap.h(),
+            )),
-                        ValidType::Integer,
-                        n2
-                    ),
-                    stub,
-                ))
-            }
-            (n1, _) => {
-                Err(self.error_form(
-                    MachineError::type_error(
-                        self.heap.h(),
-                        ValidType::Integer,
-                        n1
-                    ),
-                    stub,
-                ))
-            }
-        }
-    }
-
-    pub(crate)
-    fn and(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-        let stub = MachineError::functor_stub(clause_name!("(/\\)"), 2);
-
-        match (n1, n2) {
-            (Number::Fixnum(n1), Number::Fixnum(n2)) => {
-                Ok(Number::from(n1 & n2))
-            }
-            (Number::Fixnum(n1), Number::Integer(n2)) => {
-                let n1 = Integer::from(n1);
-                Ok(Number::from(n1 & &*n2))
-            }
-            (Number::Integer(n1), Number::Fixnum(n2)) => {
-                Ok(Number::from(&*n1 & Integer::from(n2)))
-            }
-            (Number::Integer(n1), Number::Integer(n2)) => {
-                Ok(Number::from(Integer::from(&*n1 & &*n2)))
-            }
-            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => {
-                Err(self.error_form(
-                    MachineError::type_error(
-                        self.heap.h(),
-                        ValidType::Integer,
-                        n2,
-                    ),
-                    stub,
-                ))
-            }
             (n1, _) => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n1,
-                ),
                 stub,
             )),
         }
     }
 
-    pub(crate)
+    pub(crate) fn and(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn or(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
+        let stub = MachineError::functor_stub(clause_name!("(/\\)"), 2);
+
+        match (n1, n2) {
+            (Number::Fixnum(n1), Number::Fixnum(n2)) => Ok(Number::from(n1 & n2)),
+            (Number::Fixnum(n1), Number::Integer(n2)) => {
+                let n1 = Integer::from(n1);
+                Ok(Number::from(n1 & &*n2))
+            }
+            (Number::Integer(n1), Number::Fixnum(n2)) => Ok(Number::from(&*n1 & Integer::from(n2))),
+            (Number::Integer(n1), Number::Integer(n2)) => {
+                Ok(Number::from(Integer::from(&*n1 & &*n2)))
+            }
+            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
+                stub,
+            )),
+            (n1, _) => Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
+                stub,
+            )),
+        }
+    }
+
+    pub(crate) fn or(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(\\/)"), 2);
 
         match (n1, n2) {
-            (Number::Fixnum(n1), Number::Fixnum(n2)) => {
+            (Number::Fixnum(n1), Number::Fixnum(n2)) => Ok(Number::from(n1 | n2)),
-                Ok(Number::from(n1 | n2))
-            }
             (Number::Fixnum(n1), Number::Integer(n2)) => {
                 let n1 = Integer::from(n1);
                 Ok(Number::from(n1 | &*n2))
             }
-            (Number::Integer(n1), Number::Fixnum(n2)) => {
+            (Number::Integer(n1), Number::Fixnum(n2)) => Ok(Number::from(&*n1 | Integer::from(n2))),
-                Ok(Number::from(&*n1 | Integer::from(n2)))
-            }
             (Number::Integer(n1), Number::Integer(n2)) => {
                 Ok(Number::from(Integer::from(&*n1 | &*n2)))
             }
-            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => {
+            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => Err(self.error_form(
-                Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
-                    MachineError::type_error(
+                stub,
-                        self.heap.h(),
+            )),
-                        ValidType::Integer,
+            (n1, _) => Err(self.error_form(
-                        n2,
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                    ),
+                stub,
-                    stub,
+            )),
-                ))
-            }
-            (n1, _) => {
-                Err(self.error_form(
-                    MachineError::type_error(
-                        self.heap.h(),
-                        ValidType::Integer,
-                        n1
-                    ),
-                    stub,
-                ))
-            }
         }
     }
 
-    pub(crate)
+    pub(crate) fn modulus(&self, x: Number, y: Number) -> Result<Number, MachineStub> {
-    fn modulus(&self, x: Number, y: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(mod)"), 2);
 
         match (x, y) {
             (Number::Fixnum(n1), Number::Fixnum(n2)) => {
                 if n2 == 0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
                     Ok(Number::from(n1.rem_floor(n2)))
                 }
             }
             (Number::Fixnum(n1), Number::Integer(n2)) => {
                 if &*n2 == &0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
                     let n1 = Integer::from(n1);
-                    Ok(Number::from(<(Integer, Integer)>::from(n1.div_rem_floor_ref(&*n2)).1))
+                    Ok(Number::from(
+                        <(Integer, Integer)>::from(n1.div_rem_floor_ref(&*n2)).1,
+                    ))
                 }
             }
             (Number::Integer(n1), Number::Fixnum(n2)) => {
                 if n2 == 0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
                     let n2 = Integer::from(n2);
-                    Ok(Number::from(<(Integer, Integer)>::from(n1.div_rem_floor_ref(&n2)).1))
+                    Ok(Number::from(
+                        <(Integer, Integer)>::from(n1.div_rem_floor_ref(&n2)).1,
+                    ))
                 }
             }
             (Number::Integer(x), Number::Integer(y)) => {
                 if &*y == &0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
-                    Ok(Number::from(<(Integer, Integer)>::from(x.div_rem_floor_ref(&*y)).1))
+                    Ok(Number::from(
+                        <(Integer, Integer)>::from(x.div_rem_floor_ref(&*y)).1,
+                    ))
                 }
             }
-            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => {
+            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => Err(self.error_form(
-                Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
-                    MachineError::type_error(
+                stub,
-                        self.heap.h(),
+            )),
-                        ValidType::Integer,
-                        n2,
-                    ),
-                    stub,
-                ))
-            }
             (n1, _) => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n1,
-                ),
                 stub,
             )),
         }
     }
 
-    pub(crate)
+    pub(crate) fn remainder(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn remainder(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         let stub = MachineError::functor_stub(clause_name!("(rem)"), 2);
 
         match (n1, n2) {
             (Number::Fixnum(n1), Number::Fixnum(n2)) => {
                 if n2 == 0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
                     Ok(Number::from(n1 % n2))
                 }
             }
             (Number::Fixnum(n1), Number::Integer(n2)) => {
                 if &*n2 == &0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
                     let n1 = Integer::from(n1);
                     Ok(Number::from(n1 % &*n2))
@@ -1072,10 +880,8 @@ impl MachineState {
             }
             (Number::Integer(n1), Number::Fixnum(n2)) => {
                 if n2 == 0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
                     let n2 = Integer::from(n2);
                     Ok(Number::from(&*n1 % n2))
@@ -1083,37 +889,24 @@ impl MachineState {
             }
             (Number::Integer(n1), Number::Integer(n2)) => {
                 if &*n2 == &0 {
-                    Err(self.error_form(
+                    Err(self
-                        MachineError::evaluation_error(EvalError::ZeroDivisor),
+                        .error_form(MachineError::evaluation_error(EvalError::ZeroDivisor), stub))
-                        stub,
-                    ))
                 } else {
                     Ok(Number::from(Integer::from(&*n1 % &*n2)))
                 }
             }
-            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => {
+            (Number::Integer(_), n2) | (Number::Fixnum(_), n2) => Err(self.error_form(
-                Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
-                    MachineError::type_error(
+                stub,
-                        self.heap.h(),
+            )),
-                        ValidType::Integer,
-                        n2,
-                    ),
-                    stub,
-                ))
-            }
             (n1, _) => Err(self.error_form(
-                MachineError::type_error(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
-                    self.heap.h(),
-                    ValidType::Integer,
-                    n1,
-                ),
                 stub,
             )),
         }
     }
 
-    pub(crate)
+    pub(crate) fn max(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn max(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         match (n1, n2) {
             (Number::Fixnum(n1), Number::Fixnum(n2)) => {
                 if n1 > n2 {
@@ -1154,8 +947,7 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn min(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
-    fn min(&self, n1: Number, n2: Number) -> Result<Number, MachineStub> {
         match (n1, n2) {
             (Number::Fixnum(n1), Number::Fixnum(n2)) => {
                 if n1 < n2 {
@@ -1196,8 +988,7 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn sign(&self, n: Number) -> Number {
-    fn sign(&self, n: Number) -> Number {
         if n.is_positive() {
             Number::from(1)
         } else if n.is_negative() {

src/machine/attributed_variables.rs

@@ -1,5 +1,6 @@
 use crate::heap_iter::*;
 use crate::machine::*;
+use crate::prolog_parser_rebis::temp_v;
 
 use crate::indexmap::IndexSet;
 
@@ -20,8 +21,7 @@ pub(super) struct AttrVarInitializer {
 }
 
 impl AttrVarInitializer {
-    pub(super)
+    pub(super) fn new(verify_attrs_loc: usize, project_attrs_loc: usize) -> Self {
-    fn new(verify_attrs_loc: usize, project_attrs_loc: usize) -> Self {
         AttrVarInitializer {
             attribute_goals: vec![],
             attr_var_queue: vec![],
@@ -34,24 +34,21 @@ impl AttrVarInitializer {
     }
 
     #[inline]
-    pub(super)
+    pub(super) fn reset(&mut self) {
-    fn reset(&mut self) {
+        self.attribute_goals.clear();
-	    self.attribute_goals.clear();
         self.attr_var_queue.clear();
         self.bindings.clear();
     }
 
     #[inline]
-    pub(super)
+    pub(super) fn backtrack(&mut self, queue_b: usize, bindings_b: usize) {
-    fn backtrack(&mut self, queue_b: usize, bindings_b: usize) {
         self.attr_var_queue.truncate(queue_b);
         self.bindings.truncate(bindings_b);
     }
 }
 
 impl MachineState {
-    pub(super)
+    pub(super) fn push_attr_var_binding(&mut self, h: usize, addr: Addr) {
-    fn push_attr_var_binding(&mut self, h: usize, addr: Addr) {
         if self.attr_var_init.bindings.is_empty() {
             self.attr_var_init.instigating_p = self.p.local();
 
@@ -79,7 +76,7 @@ impl MachineState {
         let iter = self
             .attr_var_init
             .bindings
-            .drain(0 ..)
+            .drain(0..)
             .map(|(_, addr)| HeapCellValue::Addr(addr));
 
         let value_list_addr = Addr::HeapCell(self.heap.to_list(iter));
@@ -97,8 +94,7 @@ impl MachineState {
         self[temp_v!(2)] = value_list_addr;
     }
 
-    pub(super)
+    pub(super) fn gather_attr_vars_created_since(&self, b: usize) -> IntoIter<Addr> {
-    fn gather_attr_vars_created_since(&self, b: usize) -> IntoIter<Addr> {
         let mut attr_vars: Vec<_> = self.attr_var_init.attr_var_queue[b..]
             .iter()
             .filter_map(|h| match self.store(self.deref(Addr::HeapCell(*h))) {
@@ -107,29 +103,25 @@ impl MachineState {
             })
             .collect();
 
-        attr_vars.sort_unstable_by(|a1, a2| {
+        attr_vars
-            self.compare_term_test(a1, a2).unwrap_or(Ordering::Less)
+            .sort_unstable_by(|a1, a2| self.compare_term_test(a1, a2).unwrap_or(Ordering::Less));
-        });
 
         self.term_dedup(&mut attr_vars);
         attr_vars.into_iter()
     }
 
-    pub(super)
+    pub(super) fn verify_attr_interrupt(&mut self, p: usize) {
-    fn verify_attr_interrupt(&mut self, p: usize) {
         self.allocate(self.num_of_args + 2);
 
         let e = self.e;
         self.stack.index_and_frame_mut(e).prelude.interrupt_cp = self.attr_var_init.cp;
 
-        for i in 1 .. self.num_of_args + 1 {
+        for i in 1..self.num_of_args + 1 {
             self.stack.index_and_frame_mut(e)[i] = self[RegType::Temp(i)];
         }
 
-        self.stack.index_and_frame_mut(e)[self.num_of_args + 1] =
+        self.stack.index_and_frame_mut(e)[self.num_of_args + 1] = Addr::CutPoint(self.b0);
-            Addr::CutPoint(self.b0);
+        self.stack.index_and_frame_mut(e)[self.num_of_args + 2] = Addr::Usize(self.num_of_args);
-        self.stack.index_and_frame_mut(e)[self.num_of_args + 2] =
-            Addr::Usize(self.num_of_args);
 
         self.verify_attributes();
 
@@ -138,9 +130,8 @@ impl MachineState {
         self.p = CodePtr::Local(LocalCodePtr::DirEntry(p));
     }
 
-    pub(super)
+    pub(super) fn attr_vars_of_term(&self, addr: Addr) -> Vec<Addr> {
-    fn attr_vars_of_term(&self, addr: Addr) -> Vec<Addr> {
+        let mut seen_set = IndexSet::new();
-        let mut seen_set  = IndexSet::new();
         let mut seen_vars = vec![];
 
         let mut iter = self.acyclic_pre_order_iter(addr);

src/machine/load_state.rs

@@ -1,7 +1,8 @@
-use crate::machine::*;
 use crate::machine::machine_indices::*;
-use crate::machine::term_stream::*;
+use crate::machine::*;
+use crate::prolog_parser_rebis::clause_name;
 
+use crate::machine::term_stream::*;
 use indexmap::IndexSet;
 
 use crate::ref_thread_local::RefThreadLocal;
@@ -19,37 +20,35 @@ pub(super) struct LoadState<'a> {
     pub(super) wam: &'a mut Machine,
 }
 
-pub(super)
+pub(super) fn set_code_index(
-fn set_code_index(
     retraction_info: &mut RetractionInfo,
     compilation_target: &CompilationTarget,
     key: PredicateKey,
     code_index: &CodeIndex,
     code_ptr: IndexPtr,
 ) {
-    let record =
+    let record = match compilation_target {
-        match compilation_target {
+        CompilationTarget::User => {
-            CompilationTarget::User => {
+            if IndexPtr::Undefined == code_index.get() {
-                if IndexPtr::Undefined == code_index.get() {
+                code_index.set(code_ptr);
-                    code_index.set(code_ptr);
+                RetractionRecord::AddedUserPredicate(key)
-                    RetractionRecord::AddedUserPredicate(key)
+            } else {
-                } else {
+                // TODO: emit warning about overwriting previous record
-                    // TODO: emit warning about overwriting previous record
+                let replaced = code_index.replace(code_ptr);
-                    let replaced = code_index.replace(code_ptr);
+                RetractionRecord::ReplacedUserPredicate(key, replaced)
-                    RetractionRecord::ReplacedUserPredicate(key, replaced)
-                }
             }
-            CompilationTarget::Module(ref module_name) => {
+        }
-                if IndexPtr::Undefined == code_index.get() {
+        CompilationTarget::Module(ref module_name) => {
-                    code_index.set(code_ptr);
+            if IndexPtr::Undefined == code_index.get() {
-                    RetractionRecord::AddedModulePredicate(module_name.clone(), key)
+                code_index.set(code_ptr);
-                } else {
+                RetractionRecord::AddedModulePredicate(module_name.clone(), key)
-                    // TODO: emit warning about overwriting previous record
+            } else {
-                    let replaced = code_index.replace(code_ptr);
+                // TODO: emit warning about overwriting previous record
-                    RetractionRecord::ReplacedModulePredicate(module_name.clone(), key, replaced)
+                let replaced = code_index.replace(code_ptr);
-                }
+                RetractionRecord::ReplacedModulePredicate(module_name.clone(), key, replaced)
             }
-        };
+        }
+    };
 
     retraction_info.push_record(record);
 }
@@ -71,16 +70,16 @@ fn add_op_decl_as_module_export(
 
     match op_decl.insert_into_op_dir(wam_op_dir) {
         Some((prec, spec)) => {
-            retraction_info.push_record(
+            retraction_info.push_record(RetractionRecord::ReplacedUserOp(
-                RetractionRecord::ReplacedUserOp(op_decl.clone(), prec, spec)
+                op_decl.clone(),
-            );
+                prec,
+                spec,
+            ));
 
             module_op_exports.push((op_decl.clone(), Some((prec, spec))));
         }
         None => {
-            retraction_info.push_record(
+            retraction_info.push_record(RetractionRecord::AddedUserOp(op_decl.clone()));
-                RetractionRecord::AddedUserOp(op_decl.clone())
-            );
 
             module_op_exports.push((op_decl.clone(), None));
         }
@@ -89,49 +88,45 @@ fn add_op_decl_as_module_export(
     add_op_decl(retraction_info, compilation_target, module_op_dir, op_decl);
 }
 
-pub(super)
+pub(super) fn add_op_decl(
-fn add_op_decl(
     retraction_info: &mut RetractionInfo,
     compilation_target: &CompilationTarget,
     op_dir: &mut OpDir,
     op_decl: &OpDecl,
 ) {
     match op_decl.insert_into_op_dir(op_dir) {
-        Some((prec, spec)) => {
+        Some((prec, spec)) => match &compilation_target {
-            match &compilation_target {
+            CompilationTarget::User => {
-                CompilationTarget::User => {
+                retraction_info.push_record(RetractionRecord::ReplacedUserOp(
-                    retraction_info.push_record(
+                    op_decl.clone(),
-                        RetractionRecord::ReplacedUserOp(op_decl.clone(), prec, spec),
+                    prec,
-                    );
+                    spec,
-                }
+                ));
-                CompilationTarget::Module(ref module_name) => {
-                    retraction_info.push_record(
-                        RetractionRecord::ReplacedModuleOp(
-                            module_name.clone(), op_decl.clone(), prec, spec,
-                        ),
-                    );
-                }
             }
-        }
+            CompilationTarget::Module(ref module_name) => {
-        None => {
+                retraction_info.push_record(RetractionRecord::ReplacedModuleOp(
-            match &compilation_target {
+                    module_name.clone(),
-                CompilationTarget::User => {
+                    op_decl.clone(),
-                    retraction_info.push_record(
+                    prec,
-                        RetractionRecord::AddedUserOp(op_decl.clone()),
+                    spec,
-                    );
+                ));
-                }
-                CompilationTarget::Module(ref module_name) => {
-                    retraction_info.push_record(
-                        RetractionRecord::AddedModuleOp(module_name.clone(), op_decl.clone()),
-                    );
-                }
             }
-        }
+        },
+        None => match &compilation_target {
+            CompilationTarget::User => {
+                retraction_info.push_record(RetractionRecord::AddedUserOp(op_decl.clone()));
+            }
+            CompilationTarget::Module(ref module_name) => {
+                retraction_info.push_record(RetractionRecord::AddedModuleOp(
+                    module_name.clone(),
+                    op_decl.clone(),
+                ));
+            }
+        },
     }
 }
 
-pub(super)
+pub(super) fn import_module_exports(
-fn import_module_exports(
     retraction_info: &mut RetractionInfo,
     compilation_target: &CompilationTarget,
     imported_module: &Module,
@@ -166,12 +161,7 @@ fn import_module_exports(
                 }
             }
             ModuleExport::OpDecl(ref op_decl) => {
-                add_op_decl(
+                add_op_decl(retraction_info, compilation_target, op_dir, op_decl);
-                    retraction_info,
-                    compilation_target,
-                    op_dir,
-                    op_decl,
-                );
             }
         }
     }
@@ -185,7 +175,7 @@ fn import_module_exports_into_module(
     op_dir: &mut OpDir,
     meta_predicates: &mut MetaPredicateDir,
     wam_op_dir: &mut OpDir,
-    module_op_exports: &mut ModuleOpExports
+    module_op_exports: &mut ModuleOpExports,
 ) {
     for export in imported_module.module_decl.exports.iter() {
         match export {
@@ -227,7 +217,6 @@ fn import_module_exports_into_module(
     }
 }
 
-
 fn import_qualified_module_exports(
     retraction_info: &mut RetractionInfo,
     compilation_target: &CompilationTarget,
@@ -263,12 +252,7 @@ fn import_qualified_module_exports(
                 }
             }
             ModuleExport::OpDecl(ref op_decl) => {
-                add_op_decl(
+                add_op_decl(retraction_info, compilation_target, op_dir, op_decl);
-                    retraction_info,
-                    compilation_target,
-                    op_dir,
-                    op_decl,
-                );
             }
         }
     }
@@ -326,29 +310,28 @@ fn import_qualified_module_exports_into_module(
 
 impl<'a> LoadState<'a> {
     #[inline]
-    pub(super)
+    pub(super) fn increment_clause_assert_margin(&mut self, incr: usize) {
-    fn increment_clause_assert_margin(&mut self, incr: usize) {
         match &self.compilation_target {
-            CompilationTarget::User => {
+            CompilationTarget::User => {}
-            }
             CompilationTarget::Module(ref module_name) => {
-                self.retraction_info.push_record(
+                self.retraction_info
-                    RetractionRecord::IncreasedClauseAssertMargin(
+                    .push_record(RetractionRecord::IncreasedClauseAssertMargin(
                         module_name.clone(),
                         incr,
-                    ),
+                    ));
-                );
 
-                self.wam.indices.modules.get_mut(module_name)
+                self.wam
+                    .indices
+                    .modules
+                    .get_mut(module_name)
                     .map(|module| module.clause_assert_margin += incr);
             }
         }
     }
 
     #[inline]
-    pub(super)
+    pub(super) fn remove_module_op_exports(&mut self) {
-    fn remove_module_op_exports(&mut self) {
+        for (mut op_decl, record) in self.module_op_exports.drain(0..) {
-        for (mut op_decl, record) in self.module_op_exports.drain(0 ..) {
             op_decl.remove(&mut self.wam.indices.op_dir);
 
             if let Some((prec, spec)) = record {
@@ -365,26 +348,28 @@ impl<'a> LoadState<'a> {
         key: PredicateKey,
     ) -> CodeIndex {
         match self.wam.indices.modules.get_mut(&module_name) {
-            Some(ref mut module) => {
+            Some(ref mut module) => module
-                module.code_dir
+                .code_dir
-                    .entry(key)
+                .entry(key)
-                    .or_insert_with(|| CodeIndex::new(IndexPtr::Undefined))
+                .or_insert_with(|| CodeIndex::new(IndexPtr::Undefined))
-                    .clone()
+                .clone(),
-            }
             None => {
                 let mut module = Module::new(
-                    ModuleDecl { name: module_name.clone(), exports: vec![] },
+                    ModuleDecl {
+                        name: module_name.clone(),
+                        exports: vec![],
+                    },
                     ListingSource::DynamicallyGenerated,
                 );
 
-                let code_index = module.code_dir
+                let code_index = module
+                    .code_dir
                     .entry(key)
                     .or_insert_with(|| CodeIndex::new(IndexPtr::Undefined))
                     .clone();
 
-                self.retraction_info.push_record(
+                self.retraction_info
-                    RetractionRecord::AddedModule(module_name.clone()),
+                    .push_record(RetractionRecord::AddedModule(module_name.clone()));
-                );
 
                 self.wam.indices.modules.insert(module_name, module);
                 code_index
@@ -392,29 +377,31 @@ impl<'a> LoadState<'a> {
         }
     }
 
-    pub(super)
+    pub(super) fn get_or_insert_code_index(&mut self, key: PredicateKey) -> CodeIndex {
-    fn get_or_insert_code_index(&mut self, key: PredicateKey) -> CodeIndex {
         match self.compilation_target.clone() {
-            CompilationTarget::User => {
+            CompilationTarget::User => self
-                self.wam.indices.code_dir
+                .wam
-                    .entry(key)
+                .indices
-                    .or_insert_with(|| CodeIndex::new(IndexPtr::Undefined))
+                .code_dir
-                    .clone()
+                .entry(key)
-            }
+                .or_insert_with(|| CodeIndex::new(IndexPtr::Undefined))
+                .clone(),
             CompilationTarget::Module(module_name) => {
                 self.get_or_insert_local_code_index(module_name, key)
             }
         }
     }
 
-    pub(super)
+    pub(super) fn get_or_insert_qualified_code_index(
-    fn get_or_insert_qualified_code_index(
         &mut self,
         module_name: ClauseName,
         key: PredicateKey,
     ) -> CodeIndex {
         if module_name.as_str() == "user" {
-            return self.wam.indices.code_dir
+            return self
+                .wam
+                .indices
+                .code_dir
                 .entry(key)
                 .or_insert_with(|| CodeIndex::new(IndexPtr::Undefined))
                 .clone();
@@ -424,15 +411,20 @@ impl<'a> LoadState<'a> {
     }
 
     #[inline]
-    pub(super)
+    pub(super) fn add_extensible_predicate(
-    fn add_extensible_predicate(&mut self, key: PredicateKey, skeleton: PredicateSkeleton) {
+        &mut self,
+        key: PredicateKey,
+        skeleton: PredicateSkeleton,
+    ) {
         match &self.compilation_target {
             CompilationTarget::User => {
-                self.wam.indices.extensible_predicates.insert(key.clone(), skeleton);
+                self.wam
+                    .indices
+                    .extensible_predicates
+                    .insert(key.clone(), skeleton);
 
-                self.retraction_info.push_record(
+                self.retraction_info
-                    RetractionRecord::AddedUserExtensiblePredicate(key),
+                    .push_record(RetractionRecord::AddedUserExtensiblePredicate(key));
-                );
             }
             CompilationTarget::Module(ref module_name) => {
                 if let Some(module) = self.wam.indices.modules.get_mut(module_name) {
@@ -448,8 +440,7 @@ impl<'a> LoadState<'a> {
         }
     }
 
-    pub(super)
+    pub(super) fn add_op_decl(&mut self, op_decl: &OpDecl) {
-    fn add_op_decl(&mut self, op_decl: &OpDecl) {
         match &self.compilation_target {
             CompilationTarget::User => {
                 add_op_decl(
@@ -479,8 +470,7 @@ impl<'a> LoadState<'a> {
         }
     }
 
-    pub(super)
+    pub(super) fn get_clause_type(
-    fn get_clause_type(
         &mut self,
         name: ClauseName,
         arity: usize,
@@ -495,14 +485,11 @@ impl<'a> LoadState<'a> {
                 let idx = self.get_or_insert_code_index((name.clone(), arity));
                 ClauseType::Op(name, fixity, idx)
             }
-            ct => {
+            ct => ct,
-                ct
-            }
         }
     }
 
-    pub(super)
+    pub(super) fn get_qualified_clause_type(
-    fn get_qualified_clause_type(
         &mut self,
         module_name: ClauseName,
         name: ClauseName,
@@ -522,14 +509,11 @@ impl<'a> LoadState<'a> {
 
                 ClauseType::Op(name, fixity, idx)
             }
-            ct => {
+            ct => ct,
-                ct
-            }
         }
     }
 
-    pub(super)
+    pub(super) fn add_meta_predicate_record(
-    fn add_meta_predicate_record(
         &mut self,
         module_name: ClauseName,
         name: ClauseName,
@@ -540,20 +524,26 @@ impl<'a> LoadState<'a> {
 
         match module_name.as_str() {
             "user" => {
-                match self.wam.indices.meta_predicates.insert(key.clone(), meta_specs) {
+                match self
+                    .wam
+                    .indices
+                    .meta_predicates
+                    .insert(key.clone(), meta_specs)
+                {
                     Some(old_meta_specs) => {
-                        self.retraction_info.push_record(
+                        self.retraction_info
-                            RetractionRecord::ReplacedMetaPredicate(
+                            .push_record(RetractionRecord::ReplacedMetaPredicate(
-                                module_name.clone(), key.0, old_meta_specs,
+                                module_name.clone(),
-                            ),
+                                key.0,
-                        );
+                                old_meta_specs,
+                            ));
                     }
                     None => {
-                        self.retraction_info.push_record(
+                        self.retraction_info
-                            RetractionRecord::AddedMetaPredicate(
+                            .push_record(RetractionRecord::AddedMetaPredicate(
-                                module_name.clone(), key,
+                                module_name.clone(),
-                            )
+                                key,
-                        );
+                            ));
                     }
                 }
             }
@@ -564,15 +554,15 @@ impl<'a> LoadState<'a> {
                             Some(old_meta_specs) => {
                                 self.retraction_info.push_record(
                                     RetractionRecord::ReplacedMetaPredicate(
-                                        module_name.clone(), key.0, old_meta_specs,
+                                        module_name.clone(),
+                                        key.0,
+                                        old_meta_specs,
                                     ),
                                 );
                             }
                             None => {
                                 self.retraction_info.push_record(
-                                    RetractionRecord::AddedMetaPredicate(
+                                    RetractionRecord::AddedMetaPredicate(module_name.clone(), key),
-                                        module_name.clone(), key,
-                                    )
                                 );
                             }
                         }
@@ -588,15 +578,14 @@ impl<'a> LoadState<'a> {
 
                         module.meta_predicates.insert(key.clone(), meta_specs);
 
-                        self.retraction_info.push_record(
+                        self.retraction_info
-                            RetractionRecord::AddedMetaPredicate(
+                            .push_record(RetractionRecord::AddedMetaPredicate(
-                                module_name.clone(), key,
+                                module_name.clone(),
-                            )
+                                key,
-                        );
+                            ));
 
-                        self.retraction_info.push_record(
+                        self.retraction_info
-                            RetractionRecord::AddedModule(module_name.clone()),
+                            .push_record(RetractionRecord::AddedModule(module_name.clone()));
-                        );
 
                         self.wam.indices.modules.insert(module_name, module);
                     }
@@ -623,32 +612,29 @@ impl<'a> LoadState<'a> {
         }
     }
 
-    pub(crate)
+    pub(crate) fn add_module(&mut self, module_decl: ModuleDecl, listing_src: ListingSource) {
-    fn add_module(&mut self, module_decl: ModuleDecl, listing_src: ListingSource) {
         let module_name = module_decl.name.clone();
 
-        let mut module =
+        let mut module = match self.wam.indices.modules.remove(&module_name) {
-            match self.wam.indices.modules.remove(&module_name) {
+            Some(mut module) => {
-                Some(mut module) => {
+                let old_module_decl = mem::replace(&mut module.module_decl, module_decl);
-                    let old_module_decl = mem::replace(&mut module.module_decl, module_decl);
 
-                    self.retraction_info.push_record(
+                self.retraction_info
-                        RetractionRecord::ReplacedModule(
+                    .push_record(RetractionRecord::ReplacedModule(
-                            old_module_decl, listing_src.clone(),
+                        old_module_decl,
-                        ),
+                        listing_src.clone(),
-                    );
+                    ));
 
-                    module.listing_src = listing_src;
+                module.listing_src = listing_src;
-                    module
+                module
-                }
+            }
-                None => {
+            None => {
-                    self.retraction_info.push_record(
+                self.retraction_info
-                        RetractionRecord::AddedModule(module_name.clone()),
+                    .push_record(RetractionRecord::AddedModule(module_name.clone()));
-                    );
 
-                    Module::new(module_decl, listing_src)
+                Module::new(module_decl, listing_src)
-                }
+            }
-            };
+        };
 
         self.import_builtins_in_module(
             &mut module.code_dir,
@@ -676,8 +662,7 @@ impl<'a> LoadState<'a> {
         self.wam.indices.modules.insert(module_name, module);
     }
 
-    pub(super)
+    pub(super) fn import_module(&mut self, module_name: ClauseName) -> Result<(), SessionError> {
-    fn import_module(&mut self, module_name: ClauseName) -> Result<(), SessionError> {
         if let Some(module) = self.wam.indices.modules.remove(&module_name) {
             match &self.compilation_target {
                 CompilationTarget::User => {
@@ -717,7 +702,9 @@ impl<'a> LoadState<'a> {
             self.wam.indices.modules.insert(module_name, module);
             Ok(())
         } else {
-            Err(SessionError::ExistenceError(ExistenceError::Module(module_name)))
+            Err(SessionError::ExistenceError(ExistenceError::Module(
+                module_name,
+            )))
         }
     }
 
@@ -765,41 +752,41 @@ impl<'a> LoadState<'a> {
             self.wam.indices.modules.insert(module_name, module);
             Ok(())
         } else {
-            Err(SessionError::ExistenceError(ExistenceError::Module(module_name)))
+            Err(SessionError::ExistenceError(ExistenceError::Module(
+                module_name,
+            )))
         }
     }
 
-    pub(crate)
+    pub(crate) fn use_module(&mut self, module_src: ModuleSource) -> Result<(), SessionError> {
-    fn use_module(&mut self, module_src: ModuleSource) -> Result<(), SessionError> {
+        let (stream, listing_src) = match module_src {
-        let (stream, listing_src) =
+            ModuleSource::File(filename) => {
-            match module_src {
+                let mut path_buf = PathBuf::from(filename.as_str());
-                ModuleSource::File(filename) => {
+                path_buf.set_extension("pl");
-                    let mut path_buf = PathBuf::from(filename.as_str());
+                let file = File::open(&path_buf)?;
-                    path_buf.set_extension("pl");
-                    let file = File::open(&path_buf)?;
 
-                    (Stream::from_file_as_input(filename.clone(), file),
+                (
-                     ListingSource::File(filename, path_buf))
+                    Stream::from_file_as_input(filename.clone(), file),
-                }
+                    ListingSource::File(filename, path_buf),
-                ModuleSource::Library(library) => {
+                )
-                    match LIBRARIES.borrow().get(library.as_str()) {
+            }
-                        Some(code) => {
+            ModuleSource::Library(library) => match LIBRARIES.borrow().get(library.as_str()) {
-                            if let Some(ref module) = self.wam.indices.modules.get(&library) {
+                Some(code) => {
-                                if let ListingSource::DynamicallyGenerated = &module.listing_src {
+                    if let Some(ref module) = self.wam.indices.modules.get(&library) {
-                                    (Stream::from(*code), ListingSource::User)
+                        if let ListingSource::DynamicallyGenerated = &module.listing_src {
-                                } else {
+                            (Stream::from(*code), ListingSource::User)
-                                    return self.import_module(library);
+                        } else {
-                                }
-                            } else {
-                                (Stream::from(*code), ListingSource::User)
-                            }
-                        }
-                        None => {
                             return self.import_module(library);
                         }
+                    } else {
+                        (Stream::from(*code), ListingSource::User)
                     }
                 }
-            };
+                None => {
+                    return self.import_module(library);
+                }
+            },
+        };
 
         let compilation_target = {
             let stream = &mut parsing_stream(stream)?;
@@ -820,43 +807,39 @@ impl<'a> LoadState<'a> {
                 // nothing to do.
                 Ok(())
             }
-            CompilationTarget::Module(module_name) => {
+            CompilationTarget::Module(module_name) => self.import_module(module_name),
-                self.import_module(module_name)
-            }
         }
     }
 
-    pub(crate)
+    pub(crate) fn use_qualified_module(
-    fn use_qualified_module(
         &mut self,
         module_src: ModuleSource,
         exports: IndexSet<ModuleExport>,
     ) -> Result<(), SessionError> {
-        let (stream, listing_src) =
+        let (stream, listing_src) = match module_src {
-            match module_src {
+            ModuleSource::File(filename) => {
-                ModuleSource::File(filename) => {
+                let mut path_buf = PathBuf::from(filename.as_str());
-                    let mut path_buf = PathBuf::from(filename.as_str());
+                path_buf.set_extension("pl");
-                    path_buf.set_extension("pl");
+                let file = File::open(&path_buf)?;
-                    let file = File::open(&path_buf)?;
 
-                    (Stream::from_file_as_input(filename.clone(), file),
+                (
-                     ListingSource::File(filename, path_buf))
+                    Stream::from_file_as_input(filename.clone(), file),
-                }
+                    ListingSource::File(filename, path_buf),
-                ModuleSource::Library(library) => {
+                )
-                    match LIBRARIES.borrow().get(library.as_str()) {
+            }
-                        Some(code) => {
+            ModuleSource::Library(library) => match LIBRARIES.borrow().get(library.as_str()) {
-                            if self.wam.indices.modules.contains_key(&library) {
+                Some(code) => {
-                                return self.import_qualified_module(library, exports);
+                    if self.wam.indices.modules.contains_key(&library) {
-                            } else {
+                        return self.import_qualified_module(library, exports);
-                                (Stream::from(*code), ListingSource::User)
+                    } else {
-                            }
+                        (Stream::from(*code), ListingSource::User)
-                        }
-                        None => {
-                            return self.import_qualified_module(library, exports);
-                        }
                     }
                 }
-            };
+                None => {
+                    return self.import_qualified_module(library, exports);
+                }
+            },
+        };
 
         let compilation_target = {
             let stream = &mut parsing_stream(stream)?;
@@ -884,12 +867,9 @@ impl<'a> LoadState<'a> {
     }
 
     #[inline]
-    pub(super)
+    pub(super) fn composite_op_dir(&self) -> CompositeOpDir {
-    fn composite_op_dir(&self) -> CompositeOpDir {
         match &self.compilation_target {
-            CompilationTarget::User => {
+            CompilationTarget::User => CompositeOpDir::new(&self.wam.indices.op_dir, None),
-                CompositeOpDir::new(&self.wam.indices.op_dir, None)
-            }
             CompilationTarget::Module(ref module_name) => {
                 match self.wam.indices.modules.get(module_name) {
                     Some(ref module) => {

src/machine/machine_errors.rs

@@ -1,4 +1,5 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::{clause_name, temp_v};
 
 use crate::forms::{ModuleSource, Number}; //, PredicateKey};
 use crate::machine::heap::*;
@@ -23,74 +24,59 @@ pub(crate) struct MachineError {
     from: ErrorProvenance,
 }
 
-pub(crate)
+pub(crate) trait TypeError {
-trait TypeError {
     fn type_error(self, h: usize, valid_type: ValidType) -> MachineError;
 }
 
 impl TypeError for Addr {
     fn type_error(self, _: usize, valid_type: ValidType) -> MachineError {
-        let stub = functor!(
+        let stub = functor!("type_error", [atom(valid_type.as_str()), addr(self)]);
-            "type_error",
-            [atom(valid_type.as_str()), addr(self)]
-        );
 
         MachineError {
             stub,
             location: None,
-            from: ErrorProvenance::Received
+            from: ErrorProvenance::Received,
         }
     }
 }
 
 impl TypeError for HeapCellValue {
     fn type_error(self, _: usize, valid_type: ValidType) -> MachineError {
-        let stub = functor!(
+        let stub = functor!("type_error", [atom(valid_type.as_str()), value(self)]);
-            "type_error",
-            [atom(valid_type.as_str()), value(self)]
-        );
 
         MachineError {
             stub,
             location: None,
-            from: ErrorProvenance::Received
+            from: ErrorProvenance::Received,
         }
     }
 }
 
 impl TypeError for MachineStub {
     fn type_error(self, h: usize, valid_type: ValidType) -> MachineError {
-        let stub = functor!(
+        let stub = functor!("type_error", [atom(valid_type.as_str()), aux(h, 0)], [self]);
-            "type_error",
-            [atom(valid_type.as_str()), aux(h, 0)],
-            [self]
-        );
 
         MachineError {
             stub,
             location: None,
-            from: ErrorProvenance::Constructed
+            from: ErrorProvenance::Constructed,
         }
     }
 }
 
 impl TypeError for Number {
     fn type_error(self, _h: usize, valid_type: ValidType) -> MachineError {
-        let stub = functor!(
+        let stub = functor!("type_error", [atom(valid_type.as_str()), number(self)]);
-            "type_error",
-            [atom(valid_type.as_str()), number(self)]
-        );
 
         MachineError {
             stub,
             location: None,
-            from: ErrorProvenance::Received
+            from: ErrorProvenance::Received,
         }
     }
 }
 
-pub(crate)
+pub(crate) trait PermissionError {
-trait PermissionError {
     fn permission_error(self, h: usize, index_str: &'static str, perm: Permission) -> MachineError;
 }
 
@@ -104,7 +90,7 @@ impl PermissionError for Addr {
         MachineError {
             stub,
             location: None,
-            from: ErrorProvenance::Received
+            from: ErrorProvenance::Received,
         }
     }
 }
@@ -120,22 +106,18 @@ impl PermissionError for MachineStub {
         MachineError {
             stub,
             location: None,
-            from: ErrorProvenance::Constructed
+            from: ErrorProvenance::Constructed,
         }
     }
 }
 
-pub(super)
+pub(super) trait DomainError {
-trait DomainError {
     fn domain_error(self, error: DomainErrorType) -> MachineError;
 }
 
 impl DomainError for Addr {
     fn domain_error(self, error: DomainErrorType) -> MachineError {
-        let stub = functor!(
+        let stub = functor!("domain_error", [atom(error.as_str()), addr(self)]);
-            "domain_error",
-            [atom(error.as_str()), addr(self)]
-        );
 
         MachineError {
             stub,
@@ -147,10 +129,7 @@ impl DomainError for Addr {
 
 impl DomainError for Number {
     fn domain_error(self, error: DomainErrorType) -> MachineError {
-        let stub = functor!(
+        let stub = functor!("domain_error", [atom(error.as_str()), number(self)]);
-            "domain_error",
-            [atom(error.as_str()), number(self)]
-        );
 
         MachineError {
             stub,
@@ -161,8 +140,7 @@ impl DomainError for Number {
 }
 
 impl MachineError {
-    pub(super)
+    pub(super) fn functor_stub(name: ClauseName, arity: usize) -> MachineStub {
-    fn functor_stub(name: ClauseName, arity: usize) -> MachineStub {
         functor!(
             "/",
             SharedOpDesc::new(400, YFX),
@@ -171,8 +149,7 @@ impl MachineError {
     }
 
     #[inline]
-    pub(super)
+    pub(super) fn interrupt_error() -> Self {
-    fn interrupt_error() -> Self {
         let stub = functor!("$interrupt_thrown");
 
         MachineError {
@@ -182,8 +159,7 @@ impl MachineError {
         }
     }
 
-    pub(super)
+    pub(super) fn evaluation_error(eval_error: EvalError) -> Self {
-    fn evaluation_error(eval_error: EvalError) -> Self {
         let stub = functor!("evaluation_error", [atom(eval_error.as_str())]);
 
         MachineError {
@@ -193,13 +169,11 @@ impl MachineError {
         }
     }
 
-    pub(super)
+    pub(super) fn type_error<T: TypeError>(h: usize, valid_type: ValidType, culprit: T) -> Self {
-    fn type_error<T: TypeError>(h: usize, valid_type: ValidType, culprit: T) -> Self {
         culprit.type_error(h, valid_type)
     }
 
-    pub(super)
+    pub(super) fn module_resolution_error(
-    fn module_resolution_error(
         h: usize,
         mod_name: ClauseName,
         name: ClauseName,
@@ -218,11 +192,7 @@ impl MachineError {
             [res_stub]
         );
 
-        let stub = functor!(
+        let stub = functor!("evaluation_error", [aux(h, 0)], [ind_stub]);
-            "evaluation_error",
-            [aux(h, 0)],
-            [ind_stub]
-        );
 
         MachineError {
             stub,
@@ -231,14 +201,10 @@ impl MachineError {
         }
     }
 
-    pub(super)
+    pub(super) fn existence_error(h: usize, err: ExistenceError) -> Self {
-    fn existence_error(h: usize, err: ExistenceError) -> Self {
         match err {
             ExistenceError::Module(name) => {
-                let stub = functor!(
+                let stub = functor!("existence_error", [atom("source_sink"), clause_name(name)]);
-                    "existence_error",
-                    [atom("source_sink"), clause_name(name)]
-                );
 
                 MachineError {
                     stub,
@@ -253,11 +219,7 @@ impl MachineError {
                     [clause_name(name), integer(arity)]
                 );
 
-                let stub = functor!(
+                let stub = functor!("existence_error", [atom("procedure"), aux(h, 0)], [culprit]);
-                    "existence_error",
-                    [atom("procedure"), aux(h, 0)],
-                    [culprit]
-                );
 
                 MachineError {
                     stub,
@@ -281,10 +243,7 @@ impl MachineError {
                 }
             }
             ExistenceError::SourceSink(culprit) => {
-                let stub = functor!(
+                let stub = functor!("existence_error", [atom("source_sink"), addr(culprit)]);
-                    "existence_error",
-                    [atom("source_sink"), addr(culprit)]
-                );
 
                 MachineError {
                     stub,
@@ -293,10 +252,7 @@ impl MachineError {
                 }
             }
             ExistenceError::Stream(culprit) => {
-                let stub = functor!(
+                let stub = functor!("existence_error", [atom("stream"), addr(culprit)]);
-                    "existence_error",
-                    [atom("stream"), addr(culprit)]
-                );
 
                 MachineError {
                     stub,
@@ -307,25 +263,18 @@ impl MachineError {
         }
     }
 
-    pub(super)
+    pub(super) fn permission_error<T: PermissionError>(
-    fn permission_error<T: PermissionError>(
         h: usize,
         err: Permission,
         index_str: &'static str,
         culprit: T,
     ) -> Self {
-        culprit.permission_error(
+        culprit.permission_error(h, index_str, err)
-            h,
-            index_str,
-            err,
-        )
     }
 
     fn arithmetic_error(h: usize, err: ArithmeticError) -> Self {
         match err {
-            ArithmeticError::UninstantiatedVar => {
+            ArithmeticError::UninstantiatedVar => Self::instantiation_error(),
-                Self::instantiation_error()
-            }
             ArithmeticError::NonEvaluableFunctor(name, arity) => {
                 let culprit = functor!(
                     "/",
@@ -339,13 +288,11 @@ impl MachineError {
     }
 
     #[inline]
-    pub(super)
+    pub(super) fn domain_error<T: DomainError>(error: DomainErrorType, culprit: T) -> Self {
-    fn domain_error<T: DomainError>(error: DomainErrorType, culprit: T) -> Self {
         culprit.domain_error(error)
     }
 
-    pub(super)
+    pub(super) fn instantiation_error() -> Self {
-    fn instantiation_error() -> Self {
         let stub = functor!("instantiation_error");
 
         MachineError {
@@ -355,8 +302,7 @@ impl MachineError {
         }
     }
 
-    pub(super)
+    pub(super) fn session_error(h: usize, err: SessionError) -> Self {
-    fn session_error(h: usize, err: SessionError) -> Self {
         match err {
             // SessionError::CannotOverwriteBuiltIn(pred_str) |
             /*
@@ -369,9 +315,7 @@ impl MachineError {
                 )
             }
             */
-            SessionError::ExistenceError(err) => {
+            SessionError::ExistenceError(err) => Self::existence_error(h, err),
-                Self::existence_error(h, err)
-            }
             // SessionError::InvalidFileName(filename) => {
             //     Self::existence_error(h, ExistenceError::Module(filename))
             // }
@@ -385,46 +329,32 @@ impl MachineError {
                 )
             }
             */
-            SessionError::ModuleCannotImportSelf(module_name) => {
+            SessionError::ModuleCannotImportSelf(module_name) => Self::permission_error(
-                Self::permission_error(
+                h,
-                    h,
+                Permission::Modify,
-                    Permission::Modify,
+                "module",
-                    "module",
+                functor!("module_cannot_import_self", [clause_name(module_name)]),
-                    functor!("module_cannot_import_self", [clause_name(module_name)]),
+            ),
-                )
+            SessionError::NamelessEntry => Self::permission_error(
-            }
+                h,
-            SessionError::NamelessEntry => {
+                Permission::Create,
-                Self::permission_error(
+                "static_procedure",
-                    h,
+                functor!("nameless_procedure"),
-                    Permission::Create,
+            ),
-                    "static_procedure",
-                    functor!("nameless_procedure")
-                )
-            }
             SessionError::OpIsInfixAndPostFix(op) => {
-                Self::permission_error(
+                Self::permission_error(h, Permission::Create, "operator", functor!(clause_name(op)))
-                    h,
-                    Permission::Create,
-                    "operator",
-                    functor!(clause_name(op)),
-                )
-            }
-            SessionError::CompilationError(err) => {
-                Self::syntax_error(h, err)
-            }
-            SessionError::QueryCannotBeDefinedAsFact => {
-                Self::permission_error(
-                    h,
-                    Permission::Create,
-                    "static_procedure",
-                    functor!("query_cannot_be_defined_as_fact")
-                )
             }
+            SessionError::CompilationError(err) => Self::syntax_error(h, err),
+            SessionError::QueryCannotBeDefinedAsFact => Self::permission_error(
+                h,
+                Permission::Create,
+                "static_procedure",
+                functor!("query_cannot_be_defined_as_fact"),
+            ),
         }
     }
 
-    pub(super)
+    pub(super) fn syntax_error<E: Into<CompilationError>>(h: usize, err: E) -> Self {
-    fn syntax_error<E: Into<CompilationError>>(h: usize, err: E) -> Self {
         let err = err.into();
 
         if let CompilationError::Arithmetic(err) = err {
@@ -434,11 +364,7 @@ impl MachineError {
         let location = err.line_and_col_num();
         let stub = err.as_functor(h);
 
-        let stub = functor!(
+        let stub = functor!("syntax_error", [aux(h, 0)], [stub]);
-            "syntax_error",
-            [aux(h, 0)],
-            [stub]
-        );
 
         MachineError {
             stub,
@@ -447,8 +373,7 @@ impl MachineError {
         }
     }
 
-    pub(super)
+    pub(super) fn representation_error(flag: RepFlag) -> Self {
-    fn representation_error(flag: RepFlag) -> Self {
         let stub = functor!("representation_error", [atom(flag.as_str())]);
 
         MachineError {
@@ -515,56 +440,39 @@ impl From<ParserError> for CompilationError {
 impl CompilationError {
     pub fn line_and_col_num(&self) -> Option<(usize, usize)> {
         match self {
-            &CompilationError::ParserError(ref err) =>
+            &CompilationError::ParserError(ref err) => err.line_and_col_num(),
-                err.line_and_col_num(),
+            _ => None,
-            _ =>
-                None
         }
     }
 
     pub fn as_functor(&self, _h: usize) -> MachineStub {
         match self {
-            &CompilationError::Arithmetic(..) =>
+            &CompilationError::Arithmetic(..) => functor!("arithmetic_error"),
-                functor!("arithmetic_error"),
             // &CompilationError::BadPendingByte =>
             //     functor!("bad_pending_byte"),
-            &CompilationError::CannotParseCyclicTerm =>
+            &CompilationError::CannotParseCyclicTerm => functor!("cannot_parse_cyclic_term"),
-                functor!("cannot_parse_cyclic_term"),
             // &CompilationError::ExpandedTermsListNotAList =>
             //     functor!("expanded_terms_list_is_not_a_list"),
-            &CompilationError::ExpectedRel =>
+            &CompilationError::ExpectedRel => functor!("expected_relation"),
-                functor!("expected_relation"),
             // &CompilationError::ExpectedTopLevelTerm =>
             //     functor!("expected_atom_or_cons_or_clause"),
-            &CompilationError::InadmissibleFact =>
+            &CompilationError::InadmissibleFact => functor!("inadmissible_fact"),
-                functor!("inadmissible_fact"),
+            &CompilationError::InadmissibleQueryTerm => functor!("inadmissible_query_term"),
-            &CompilationError::InadmissibleQueryTerm =>
+            &CompilationError::InconsistentEntry => functor!("inconsistent_entry"),
-                functor!("inadmissible_query_term"),
-            &CompilationError::InconsistentEntry =>
-                functor!("inconsistent_entry"),
             // &CompilationError::InvalidDoubleQuotesDecl =>
             //     functor!("invalid_double_quotes_declaration"),
             // &CompilationError::InvalidHook =>
             //     functor!("invalid_hook"),
-            &CompilationError::InvalidMetaPredicateDecl =>
+            &CompilationError::InvalidMetaPredicateDecl => functor!("invalid_meta_predicate_decl"),
-                functor!("invalid_meta_predicate_decl"),
+            &CompilationError::InvalidModuleDecl => functor!("invalid_module_declaration"),
-            &CompilationError::InvalidModuleDecl =>
+            &CompilationError::InvalidModuleExport => functor!("invalid_module_export"),
-                functor!("invalid_module_declaration"),
+            &CompilationError::InvalidModuleResolution(ref module_name) => {
-            &CompilationError::InvalidModuleExport =>
+                functor!("no_such_module", [clause_name(module_name.clone())])
-                functor!("invalid_module_export"),
+            }
-            &CompilationError::InvalidModuleResolution(ref module_name) =>
+            &CompilationError::InvalidRuleHead => functor!("invalid_head_of_rule"),
-                functor!(
+            &CompilationError::InvalidUseModuleDecl => functor!("invalid_use_module_declaration"),
-                    "no_such_module",
+            &CompilationError::ParserError(ref err) => functor!(err.as_str()),
-                    [clause_name(module_name.clone())]
+            &CompilationError::UnreadableTerm => functor!("unreadable_term"),
-                ),
-            &CompilationError::InvalidRuleHead =>
-                functor!("invalid_head_of_rule"),
-            &CompilationError::InvalidUseModuleDecl =>
-                functor!("invalid_use_module_declaration"),
-            &CompilationError::ParserError(ref err) =>
-                functor!(err.as_str()),
-            &CompilationError::UnreadableTerm =>
-                functor!("unreadable_term"),
         }
     }
 }
@@ -715,16 +623,15 @@ impl EvalError {
 pub(super) enum CycleSearchResult {
     EmptyList,
     NotList,
-    PartialList(usize, Ref),           // the list length (up to max), and an offset into the heap.
+    PartialList(usize, Ref), // the list length (up to max), and an offset into the heap.
-    ProperList(usize),                 // the list length.
+    ProperList(usize),       // the list length.
     PStrLocation(usize, usize, usize), // the list length (up to max), the heap offset, byte offset into the string.
     UntouchedList(usize),              // the address of an uniterated Addr::Lis(address).
 }
 
 impl MachineState {
     // see 8.4.3 of Draft Technical Corrigendum 2.
-    pub(super)
+    pub(super) fn check_sort_errors(&self) -> CallResult {
-    fn check_sort_errors(&self) -> CallResult {
         let stub = MachineError::functor_stub(clause_name!("sort"), 2);
         let list = self.store(self.deref(self[temp_v!(1)].clone()));
         let sorted = self.store(self.deref(self[temp_v!(2)].clone()));
@@ -734,7 +641,9 @@ impl MachineState {
                 return Err(self.error_form(MachineError::instantiation_error(), stub))
             }
             CycleSearchResult::NotList => {
-                return Err(self.error_form(MachineError::type_error(0, ValidType::List, list), stub))
+                return Err(
+                    self.error_form(MachineError::type_error(0, ValidType::List, list), stub)
+                )
             }
             _ => {}
         };
@@ -766,7 +675,8 @@ impl MachineState {
                                 new_l = l;
                             }
                             HeapCellValue::NamedStr(2, ref name, Some(_))
-                                if name.as_str() == "-" => {
+                                if name.as_str() == "-" =>
+                            {
                                 break;
                             }
                             HeapCellValue::Addr(Addr::HeapCell(_)) => {
@@ -793,11 +703,10 @@ impl MachineState {
     }
 
     // see 8.4.4 of Draft Technical Corrigendum 2.
-    pub(super)
+    pub(super) fn check_keysort_errors(&self) -> CallResult {
-    fn check_keysort_errors(&self) -> CallResult {
         let stub = MachineError::functor_stub(clause_name!("keysort"), 2);
 
-        let pairs  = self.store(self.deref(self[temp_v!(1)].clone()));
+        let pairs = self.store(self.deref(self[temp_v!(1)].clone()));
         let sorted = self.store(self.deref(self[temp_v!(2)].clone()));
 
         match self.detect_cycles(pairs.clone()) {
@@ -814,8 +723,7 @@ impl MachineState {
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn type_error<T: TypeError>(
-    fn type_error<T: TypeError>(
         &self,
         valid_type: ValidType,
         culprit: T,
@@ -823,33 +731,25 @@ impl MachineState {
         arity: usize,
     ) -> MachineStub {
         let stub = MachineError::functor_stub(caller, arity);
-        let err = MachineError::type_error(
+        let err = MachineError::type_error(self.heap.h(), valid_type, culprit);
-            self.heap.h(),
-            valid_type,
-            culprit,
-        );
 
         return self.error_form(err, stub);
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn representation_error(
-    fn representation_error(
         &self,
         rep_flag: RepFlag,
         caller: ClauseName,
         arity: usize,
     ) -> MachineStub {
         let stub = MachineError::functor_stub(caller, arity);
-        let err = MachineError::representation_error(
+        let err = MachineError::representation_error(rep_flag);
-            rep_flag,
-        );
 
         return self.error_form(err, stub);
     }
 
-    pub(super)
+    pub(super) fn error_form(&self, err: MachineError, src: MachineStub) -> MachineStub {
-    fn error_form(&self, err: MachineError, src: MachineStub) -> MachineStub {
         let location = err.location;
         let err_len = err.len();
 
@@ -874,8 +774,7 @@ impl MachineState {
         stub
     }
 
-    pub(super)
+    pub(super) fn throw_exception(&mut self, err: MachineStub) {
-    fn throw_exception(&mut self, err: MachineStub) {
         let h = self.heap.h();
 
         self.ball.boundary = 0;

src/machine/machine_indices.rs

@@ -1,18 +1,19 @@
 use crate::prolog_parser_rebis::ast::*;
+use crate::prolog_parser_rebis::clause_name;
 
 use crate::clause_types::*;
 use crate::fixtures::*;
 use crate::forms::*;
-use crate::machine::CompilationTarget;
+use crate::instructions::*;
 use crate::machine::code_repo::CodeRepo;
-use crate::machine::Ball;
 use crate::machine::heap::*;
 use crate::machine::machine_state::*;
 use crate::machine::partial_string::*;
 use crate::machine::raw_block::RawBlockTraits;
 use crate::machine::streams::Stream;
 use crate::machine::term_stream::LoadStatePayload;
-use crate::instructions::*;
+use crate::machine::Ball;
+use crate::machine::CompilationTarget;
 use crate::ordered_float::OrderedFloat;
 use crate::rug::{Integer, Rational};
 
@@ -96,20 +97,14 @@ impl Ord for Ref {
     fn cmp(&self, other: &Ref) -> Ordering {
         match (self, other) {
             (Ref::AttrVar(h1), Ref::AttrVar(h2))
-          | (Ref::HeapCell(h1), Ref::HeapCell(h2))
+            | (Ref::HeapCell(h1), Ref::HeapCell(h2))
-          | (Ref::HeapCell(h1), Ref::AttrVar(h2))
+            | (Ref::HeapCell(h1), Ref::AttrVar(h2))
-          | (Ref::AttrVar(h1), Ref::HeapCell(h2)) => {
+            | (Ref::AttrVar(h1), Ref::HeapCell(h2)) => h1.cmp(&h2),
-                h1.cmp(&h2)
-            }
             (Ref::StackCell(fr1, sc1), Ref::StackCell(fr2, sc2)) => {
                 fr1.cmp(&fr2).then_with(|| sc1.cmp(&sc2))
             }
-            (Ref::StackCell(..), _) => {
+            (Ref::StackCell(..), _) => Ordering::Greater,
-                Ordering::Greater
+            (_, Ref::StackCell(..)) => Ordering::Less,
-            }
-            (_, Ref::StackCell(..)) => {
-                Ordering::Less
-            }
         }
     }
 }
@@ -124,35 +119,23 @@ impl PartialEq<Ref> for Addr {
 impl PartialOrd<Ref> for Addr {
     fn partial_cmp(&self, r: &Ref) -> Option<Ordering> {
         match self {
-            &Addr::StackCell(fr, sc) => {
+            &Addr::StackCell(fr, sc) => match *r {
-                match *r {
+                Ref::AttrVar(_) | Ref::HeapCell(_) => Some(Ordering::Greater),
-                    Ref::AttrVar(_) | Ref::HeapCell(_) => {
+                Ref::StackCell(fr1, sc1) => {
+                    if fr1 < fr || (fr1 == fr && sc1 < sc) {
                         Some(Ordering::Greater)
-                    }
+                    } else if fr1 == fr && sc1 == sc {
-                    Ref::StackCell(fr1, sc1) => {
+                        Some(Ordering::Equal)
-                        if fr1 < fr || (fr1 == fr && sc1 < sc) {
+                    } else {
-                            Some(Ordering::Greater)
-                        } else if fr1 == fr && sc1 == sc {
-                            Some(Ordering::Equal)
-                        } else {
-                            Some(Ordering::Less)
-                        }
-                    }
-                }
-            }
-            &Addr::HeapCell(h) | &Addr::AttrVar(h) => {
-                match r {
-                    Ref::StackCell(..) => {
                         Some(Ordering::Less)
                     }
-                    Ref::AttrVar(h1) | Ref::HeapCell(h1) => {
-                        h.partial_cmp(h1)
-                    }
                 }
-            }
+            },
-            _ => {
+            &Addr::HeapCell(h) | &Addr::AttrVar(h) => match r {
-                None
+                Ref::StackCell(..) => Some(Ordering::Less),
-            }
+                Ref::AttrVar(h1) | Ref::HeapCell(h1) => h.partial_cmp(h1),
+            },
+            _ => None,
         }
     }
 }
@@ -161,26 +144,21 @@ impl Addr {
     #[inline]
     pub fn is_heap_bound(&self) -> bool {
         match self {
-            Addr::Char(_) | Addr::EmptyList |
+            Addr::Char(_)
-            Addr::CutPoint(_) | Addr::Usize(_) | Addr::Fixnum(_) |
+            | Addr::EmptyList
-            Addr::Float(_) => {
+            | Addr::CutPoint(_)
-                false
+            | Addr::Usize(_)
-            }
+            | Addr::Fixnum(_)
-            _ => {
+            | Addr::Float(_) => false,
-                true
+            _ => true,
-            }
         }
     }
 
     #[inline]
     pub fn is_ref(&self) -> bool {
         match self {
-            Addr::HeapCell(_) | Addr::StackCell(_, _) | Addr::AttrVar(_) => {
+            Addr::HeapCell(_) | Addr::StackCell(_, _) | Addr::AttrVar(_) => true,
-                true
+            _ => false,
-            }
-            _ => {
-                false
-            }
         }
     }
 
@@ -194,92 +172,54 @@ impl Addr {
         }
     }
 
-    pub(super)
+    pub(super) fn order_category(&self, heap: &Heap) -> Option<TermOrderCategory> {
-    fn order_category(&self, heap: &Heap) -> Option<TermOrderCategory> {
         match Number::try_from((*self, heap)) {
             Ok(Number::Integer(_)) | Ok(Number::Fixnum(_)) | Ok(Number::Rational(_)) => {
                 Some(TermOrderCategory::Integer)
             }
-            Ok(Number::Float(_)) => {
+            Ok(Number::Float(_)) => Some(TermOrderCategory::FloatingPoint),
-                Some(TermOrderCategory::FloatingPoint)
+            _ => match self {
-            }
+                Addr::HeapCell(_) | Addr::AttrVar(_) | Addr::StackCell(..) => {
-            _ => {
+                    Some(TermOrderCategory::Variable)
-                match self {
-                    Addr::HeapCell(_) | Addr::AttrVar(_) | Addr::StackCell(..) => {
-                        Some(TermOrderCategory::Variable)
-                    }
-                    Addr::Float(_) => {
-                        Some(TermOrderCategory::FloatingPoint)
-                    }
-                    &Addr::Con(h) => {
-                        match &heap[h] {
-                            HeapCellValue::Atom(..) => {
-                                Some(TermOrderCategory::Atom)
-                            }
-                            HeapCellValue::DBRef(_) => {
-                                None
-                            }
-                            _ => {
-                                unreachable!()
-                            }
-                        }
-                    }
-                    Addr::Char(_) | Addr::EmptyList => {
-                        Some(TermOrderCategory::Atom)
-                    }
-                    Addr::Fixnum(_) | Addr::Usize(_) => {
-                        Some(TermOrderCategory::Integer)
-                    }
-                    Addr::Lis(_) | Addr::PStrLocation(..) | Addr::Str(_) => {
-                        Some(TermOrderCategory::Compound)
-                    }
-                    Addr::CutPoint(_) | Addr::LoadStatePayload(_) | Addr::Stream(_) | Addr::TcpListener(_) => {
-                        None
-                    }
                 }
-            }
+                Addr::Float(_) => Some(TermOrderCategory::FloatingPoint),
+                &Addr::Con(h) => match &heap[h] {
+                    HeapCellValue::Atom(..) => Some(TermOrderCategory::Atom),
+                    HeapCellValue::DBRef(_) => None,
+                    _ => {
+                        unreachable!()
+                    }
+                },
+                Addr::Char(_) | Addr::EmptyList => Some(TermOrderCategory::Atom),
+                Addr::Fixnum(_) | Addr::Usize(_) => Some(TermOrderCategory::Integer),
+                Addr::Lis(_) | Addr::PStrLocation(..) | Addr::Str(_) => {
+                    Some(TermOrderCategory::Compound)
+                }
+                Addr::CutPoint(_)
+                | Addr::LoadStatePayload(_)
+                | Addr::Stream(_)
+                | Addr::TcpListener(_) => None,
+            },
         }
     }
 
     pub fn as_constant_index(&self, machine_st: &MachineState) -> Option<Constant> {
         match self {
-            &Addr::Char(c) => {
+            &Addr::Char(c) => Some(Constant::Char(c)),
-                Some(Constant::Char(c))
+            &Addr::Con(h) => match &machine_st.heap[h] {
-            }
+                &HeapCellValue::Atom(ref name, _) if name.is_char() => {
-            &Addr::Con(h) => {
+                    Some(Constant::Char(name.as_str().chars().next().unwrap()))
-                match &machine_st.heap[h] {
-                    &HeapCellValue::Atom(ref name, _) if name.is_char() => {
-                        Some(Constant::Char(name.as_str().chars().next().unwrap()))
-                    }
-                    &HeapCellValue::Atom(ref name, _) => {
-                        Some(Constant::Atom(name.clone(), None))
-                    }
-                    &HeapCellValue::Integer(ref n) => {
-                        Some(Constant::Integer(n.clone()))
-                    }
-                    &HeapCellValue::Rational(ref n) => {
-                        Some(Constant::Rational(n.clone()))
-                    }
-                    _ => {
-                        None
-                    }
                 }
-            }
+                &HeapCellValue::Atom(ref name, _) => Some(Constant::Atom(name.clone(), None)),
-            &Addr::EmptyList => {
+                &HeapCellValue::Integer(ref n) => Some(Constant::Integer(n.clone())),
-                Some(Constant::EmptyList)
+                &HeapCellValue::Rational(ref n) => Some(Constant::Rational(n.clone())),
-            }
+                _ => None,
-            &Addr::Fixnum(n) => {
+            },
-                Some(Constant::Fixnum(n))
+            &Addr::EmptyList => Some(Constant::EmptyList),
-            }
+            &Addr::Fixnum(n) => Some(Constant::Fixnum(n)),
-            &Addr::Float(f) => {
+            &Addr::Float(f) => Some(Constant::Float(f)),
-                Some(Constant::Float(f))
+            &Addr::Usize(n) => Some(Constant::Usize(n)),
-            }
+            _ => None,
-            &Addr::Usize(n) => {
-                Some(Constant::Usize(n))
-            }
-            _ => {
-                None
-            }
         }
     }
 
@@ -383,61 +323,37 @@ impl HeapCellValue {
     #[inline]
     pub fn as_addr(&self, focus: usize) -> Addr {
         match self {
-            HeapCellValue::Addr(ref a) => {
+            HeapCellValue::Addr(ref a) => *a,
-                *a
+            HeapCellValue::Atom(..)
-            }
+            | HeapCellValue::DBRef(..)
-            HeapCellValue::Atom(..) | HeapCellValue::DBRef(..) | HeapCellValue::Integer(..) |
+            | HeapCellValue::Integer(..)
-            HeapCellValue::Rational(..) => {
+            | HeapCellValue::Rational(..) => Addr::Con(focus),
-                Addr::Con(focus)
+            HeapCellValue::LoadStatePayload(_) => Addr::LoadStatePayload(focus),
-            }
+            HeapCellValue::NamedStr(_, _, _) => Addr::Str(focus),
-            HeapCellValue::LoadStatePayload(_) => {
+            HeapCellValue::PartialString(..) => Addr::PStrLocation(focus, 0),
-                Addr::LoadStatePayload(focus)
+            HeapCellValue::Stream(_) => Addr::Stream(focus),
-            }
+            HeapCellValue::TcpListener(_) => Addr::TcpListener(focus),
-            HeapCellValue::NamedStr(_, _, _) => {
-                Addr::Str(focus)
-            }
-            HeapCellValue::PartialString(..) => {
-                Addr::PStrLocation(focus, 0)
-            }
-            HeapCellValue::Stream(_) => {
-                Addr::Stream(focus)
-            }
-            HeapCellValue::TcpListener(_) => {
-                Addr::TcpListener(focus)
-            }
         }
     }
 
     #[inline]
     pub fn context_free_clone(&self) -> HeapCellValue {
         match self {
-            &HeapCellValue::Addr(addr) => {
+            &HeapCellValue::Addr(addr) => HeapCellValue::Addr(addr),
-                HeapCellValue::Addr(addr)
+            &HeapCellValue::Atom(ref name, ref op) => HeapCellValue::Atom(name.clone(), op.clone()),
-            }
+            &HeapCellValue::DBRef(ref db_ref) => HeapCellValue::DBRef(db_ref.clone()),
-            &HeapCellValue::Atom(ref name, ref op) => {
+            &HeapCellValue::Integer(ref n) => HeapCellValue::Integer(n.clone()),
-                HeapCellValue::Atom(name.clone(), op.clone())
-            }
-            &HeapCellValue::DBRef(ref db_ref) => {
-                HeapCellValue::DBRef(db_ref.clone())
-            }
-            &HeapCellValue::Integer(ref n) => {
-                HeapCellValue::Integer(n.clone())
-            }
             &HeapCellValue::LoadStatePayload(_) => {
                 HeapCellValue::Atom(clause_name!("$live_term_stream"), None)
             }
             &HeapCellValue::NamedStr(arity, ref name, ref op) => {
                 HeapCellValue::NamedStr(arity, name.clone(), op.clone())
             }
-            &HeapCellValue::Rational(ref r) => {
+            &HeapCellValue::Rational(ref r) => HeapCellValue::Rational(r.clone()),
-                HeapCellValue::Rational(r.clone())
-            }
             &HeapCellValue::PartialString(ref pstr, has_tail) => {
                 HeapCellValue::PartialString(pstr.clone(), has_tail)
             }
-            &HeapCellValue::Stream(ref stream) => {
+            &HeapCellValue::Stream(ref stream) => HeapCellValue::Stream(stream.clone()),
-                HeapCellValue::Stream(stream.clone())
-            }
             &HeapCellValue::TcpListener(_) => {
                 HeapCellValue::Atom(clause_name!("$tcp_listener"), None)
             }
@@ -473,8 +389,7 @@ impl Deref for CodeIndex {
 
 impl CodeIndex {
     #[inline]
-    pub(super)
+    pub(super) fn new(ptr: IndexPtr) -> Self {
-    fn new(ptr: IndexPtr) -> Self {
         CodeIndex(Rc::new(Cell::new(ptr)))
     }
 
@@ -482,7 +397,7 @@ impl CodeIndex {
     pub fn is_undefined(&self) -> bool {
         match self.0.get() {
             IndexPtr::Undefined => true, // | &IndexPtr::DynamicUndefined => true,
-            _ => false
+            _ => false,
         }
     }
 
@@ -536,7 +451,7 @@ pub enum CodePtr {
     CallN(usize, LocalCodePtr, bool),               // arity, local, last call.
     Local(LocalCodePtr),
     // DynamicTransaction(DynamicTransactionType, LocalCodePtr), // the type of transaction, the return pointer.
-    REPL(REPLCodePtr, LocalCodePtr),                          // the REPL code, the return pointer.
+    REPL(REPLCodePtr, LocalCodePtr), // the REPL code, the return pointer.
     VerifyAttrInterrupt(usize), // location of the verify attribute interrupt code in the CodeDir.
 }
 
@@ -544,10 +459,10 @@ impl CodePtr {
     pub fn local(&self) -> LocalCodePtr {
         match self {
             &CodePtr::BuiltInClause(_, ref local)
-          | &CodePtr::CallN(_, ref local, _)
+            | &CodePtr::CallN(_, ref local, _)
-          | &CodePtr::Local(ref local) => local.clone(),
+            | &CodePtr::Local(ref local) => local.clone(),
             &CodePtr::VerifyAttrInterrupt(p) => LocalCodePtr::DirEntry(p),
-            &CodePtr::REPL(_, p) => p // | &CodePtr::DynamicTransaction(_, p) => p,
+            &CodePtr::REPL(_, p) => p, // | &CodePtr::DynamicTransaction(_, p) => p,
         }
     }
 
@@ -566,12 +481,11 @@ pub enum LocalCodePtr {
     DirEntry(usize), // offset
     Halt,
     IndexingBuf(usize, usize, usize), // DirEntry offset, first internal offset, second internal offset
-    // TopLevel(usize, usize), // chunk_num, offset
+                                      // TopLevel(usize, usize), // chunk_num, offset
 }
 
 impl LocalCodePtr {
-    pub(crate)
+    pub(crate) fn assign_if_local(&mut self, cp: CodePtr) {
-    fn assign_if_local(&mut self, cp: CodePtr) {
         match cp {
             CodePtr::Local(local) => *self = local,
             _ => {}
@@ -579,8 +493,7 @@ impl LocalCodePtr {
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn abs_loc(&self) -> usize {
-    fn abs_loc(&self) -> usize {
         match self {
             LocalCodePtr::DirEntry(ref p) => *p,
             LocalCodePtr::IndexingBuf(ref p, ..) => *p,
@@ -588,35 +501,28 @@ impl LocalCodePtr {
         }
     }
 
-    pub(crate)
+    pub(crate) fn is_reset_cont_marker(&self, code_repo: &CodeRepo, last_call: bool) -> bool {
-    fn is_reset_cont_marker(&self, code_repo: &CodeRepo, last_call: bool) -> bool {
         match code_repo.lookup_instr(last_call, &CodePtr::Local(*self)) {
-            Some(line) => {
+            Some(line) => match line.as_ref() {
-                match line.as_ref() {
+                Line::Control(ControlInstruction::CallClause(ref ct, ..)) => {
-                    Line::Control(ControlInstruction::CallClause(ref ct, ..)) => {
+                    if let ClauseType::System(SystemClauseType::ResetContinuationMarker) = *ct {
-                        if let ClauseType::System(SystemClauseType::ResetContinuationMarker) = *ct {
+                        return true;
-                            return true;
-                        }
                     }
-                    _ => {}
                 }
-            }
+                _ => {}
+            },
             None => {}
         }
 
         false
     }
 
-    pub(crate)
+    pub(crate) fn as_functor<T: RawBlockTraits>(&self, heap: &mut HeapTemplate<T>) -> Addr {
-    fn as_functor<T: RawBlockTraits>(&self, heap: &mut HeapTemplate<T>) -> Addr {
         let addr = Addr::HeapCell(heap.h());
 
         match self {
             LocalCodePtr::DirEntry(p) => {
-                heap.append(functor!(
+                heap.append(functor!("dir_entry", [integer(*p)]));
-                    "dir_entry",
-                    [integer(*p)]
-                ));
             }
             LocalCodePtr::Halt => {
                 heap.append(functor!("halt"));
@@ -658,7 +564,7 @@ impl PartialOrd<CodePtr> for CodePtr {
 impl PartialOrd<LocalCodePtr> for LocalCodePtr {
     fn partial_cmp(&self, other: &LocalCodePtr) -> Option<Ordering> {
         match (self, other) {
-	        (&LocalCodePtr::DirEntry(p1), &LocalCodePtr::DirEntry(ref p2)) |
+            (&LocalCodePtr::DirEntry(p1), &LocalCodePtr::DirEntry(ref p2)) |
             (&LocalCodePtr::TopLevel(_, p1), &LocalCodePtr::TopLevel(_, ref p2)) => {
                 p1.partial_cmp(p2)
             }
@@ -693,12 +599,9 @@ impl Add<usize> for LocalCodePtr {
     #[inline]
     fn add(self, rhs: usize) -> Self::Output {
         match self {
-            LocalCodePtr::DirEntry(p) =>
+            LocalCodePtr::DirEntry(p) => LocalCodePtr::DirEntry(p + rhs),
-                LocalCodePtr::DirEntry(p + rhs),
+            LocalCodePtr::Halt => unreachable!(),
-            LocalCodePtr::Halt =>
+            LocalCodePtr::IndexingBuf(p, o, i) => LocalCodePtr::IndexingBuf(p, o, i + rhs),
-                unreachable!(),
-            LocalCodePtr::IndexingBuf(p, o, i) =>
-                LocalCodePtr::IndexingBuf(p, o, i + rhs),
         }
     }
 }
@@ -709,12 +612,11 @@ impl Sub<usize> for LocalCodePtr {
     #[inline]
     fn sub(self, rhs: usize) -> Self::Output {
         match self {
-            LocalCodePtr::DirEntry(p) =>
+            LocalCodePtr::DirEntry(p) => p.checked_sub(rhs).map(LocalCodePtr::DirEntry),
-                p.checked_sub(rhs).map(LocalCodePtr::DirEntry),
+            LocalCodePtr::Halt => unreachable!(),
-            LocalCodePtr::Halt =>
+            LocalCodePtr::IndexingBuf(p, o, i) => i
-                unreachable!(),
+                .checked_sub(rhs)
-            LocalCodePtr::IndexingBuf(p, o, i) =>
+                .map(|r| LocalCodePtr::IndexingBuf(p, o, r)),
-                i.checked_sub(rhs).map(|r| LocalCodePtr::IndexingBuf(p, o, r)),
         }
     }
 }
@@ -723,15 +625,12 @@ impl SubAssign<usize> for LocalCodePtr {
     #[inline]
     fn sub_assign(&mut self, rhs: usize) {
         match self {
-            LocalCodePtr::DirEntry(ref mut p) =>
+            LocalCodePtr::DirEntry(ref mut p) => *p -= rhs,
-                *p -= rhs,
+            LocalCodePtr::Halt | LocalCodePtr::IndexingBuf(..) => unreachable!(),
-            LocalCodePtr::Halt | LocalCodePtr::IndexingBuf(..) =>
-                unreachable!(),
         }
     }
 }
 
-
 impl AddAssign<usize> for LocalCodePtr {
     #[inline]
     fn add_assign(&mut self, rhs: usize) {
@@ -749,14 +648,12 @@ impl Add<usize> for CodePtr {
 
     fn add(self, rhs: usize) -> Self::Output {
         match self {
-            p @ CodePtr::REPL(..) |
+            p @ CodePtr::REPL(..) | p @ CodePtr::VerifyAttrInterrupt(_) => {
-            p @ CodePtr::VerifyAttrInterrupt(_) => { // |
+                // |
-            // p @ CodePtr::DynamicTransaction(..) => {
+                // p @ CodePtr::DynamicTransaction(..) => {
                 p
             }
-            CodePtr::Local(local) => {
+            CodePtr::Local(local) => CodePtr::Local(local + rhs),
-                CodePtr::Local(local + rhs)
-            }
             CodePtr::BuiltInClause(_, local) | CodePtr::CallN(_, local, _) => {
                 CodePtr::Local(local + rhs)
             }
@@ -784,7 +681,6 @@ impl SubAssign<usize> for CodePtr {
     }
 }
 
-
 pub type HeapVarDict = IndexMap<Rc<Var>, Addr>;
 pub type AllocVarDict = IndexMap<Rc<Var>, VarData>;
 
@@ -830,23 +726,17 @@ impl IndexStore {
         key: &PredicateKey,
     ) -> Option<&mut PredicateSkeleton> {
         match (key.0.as_str(), key.1) {
-            ("term_expansion", 2) => {
+            ("term_expansion", 2) => self.extensible_predicates.get_mut(key),
-                self.extensible_predicates.get_mut(key)
+            _ => match compilation_target {
-            }
+                CompilationTarget::User => self.extensible_predicates.get_mut(key),
-            _ => {
+                CompilationTarget::Module(ref module_name) => {
-                match compilation_target {
+                    if let Some(module) = self.modules.get_mut(module_name) {
-                    CompilationTarget::User => {
+                        module.extensible_predicates.get_mut(key)
-                        self.extensible_predicates.get_mut(key)
+                    } else {
-                    }
+                        None
-                    CompilationTarget::Module(ref module_name) => {
-                        if let Some(module) = self.modules.get_mut(module_name) {
-                            module.extensible_predicates.get_mut(key)
-                        } else {
-                            None
-                        }
                     }
                 }
-            }
+            },
         }
     }
 
@@ -858,19 +748,17 @@ impl IndexStore {
         match (key.0.as_str(), key.1) {
             ("term_expansion", 2) => {
                 self.extensible_predicates.remove(key);
-            },
+            }
-            _ => {
+            _ => match compilation_target {
-                match compilation_target {
+                CompilationTarget::User => {
-                    CompilationTarget::User => {
+                    self.extensible_predicates.remove(key);
-                        self.extensible_predicates.remove(key);
+                }
-                    }
+                CompilationTarget::Module(ref module_name) => {
-                    CompilationTarget::Module(ref module_name) => {
+                    if let Some(module) = self.modules.get_mut(module_name) {
-                        if let Some(module) = self.modules.get_mut(module_name) {
+                        module.extensible_predicates.remove(key);
-                            module.extensible_predicates.remove(key);
-                        }
                     }
                 }
-            }
+            },
         }
     }
 
@@ -883,15 +771,9 @@ impl IndexStore {
     ) -> Option<CodeIndex> {
         if module.as_str() == "user" {
             match ClauseType::from(name, arity, op_spec) {
-                ClauseType::Named(name, arity, _) => {
+                ClauseType::Named(name, arity, _) => self.code_dir.get(&(name, arity)).cloned(),
-                    self.code_dir.get(&(name, arity)).cloned()
+                ClauseType::Op(name, spec, ..) => self.code_dir.get(&(name, spec.arity())).cloned(),
-                }
+                _ => None,
-                ClauseType::Op(name, spec, ..) => {
-                    self.code_dir.get(&(name, spec.arity())).cloned()
-                }
-                _ => {
-                    None
-                }
             }
         } else {
             self.modules.get(&module).and_then(|module| {
@@ -902,9 +784,7 @@ impl IndexStore {
                     ClauseType::Op(name, spec, ..) => {
                         module.code_dir.get(&(name, spec.arity())).cloned()
                     }
-                    _ => {
+                    _ => None,
-                        None
-                    }
                 }
             })
         }
@@ -917,44 +797,32 @@ impl IndexStore {
         compilation_target: &CompilationTarget,
     ) -> Option<&Vec<MetaSpec>> {
         match compilation_target {
-            CompilationTarget::User => {
+            CompilationTarget::User => self.meta_predicates.get(&(name, arity)),
-                self.meta_predicates.get(&(name, arity))
+            CompilationTarget::Module(ref module_name) => match self.modules.get(module_name) {
-            }
+                Some(ref module) => module
-            CompilationTarget::Module(ref module_name) => {
+                    .meta_predicates
-                match self.modules.get(module_name) {
+                    .get(&(name.clone(), arity))
-                    Some(ref module) => {
+                    .or_else(|| self.meta_predicates.get(&(name, arity))),
-                        module.meta_predicates.get(&(name.clone(), arity))
+                None => self.meta_predicates.get(&(name, arity)),
-                              .or_else(|| {
+            },
-                                  self.meta_predicates.get(&(name, arity))
-                              })
-                    }
-                    None => {
-                        self.meta_predicates.get(&(name, arity))
-                    }
-                }
-            }
         }
     }
 
     pub fn is_dynamic_predicate(&self, module_name: ClauseName, key: PredicateKey) -> bool {
         match module_name.as_str() {
-            "user" => {
+            "user" => self
-                self.extensible_predicates.get(&key)
+                .extensible_predicates
+                .get(&key)
+                .map(|skeleton| skeleton.is_dynamic)
+                .unwrap_or(false),
+            _ => match self.modules.get(&module_name) {
+                Some(ref module) => module
+                    .extensible_predicates
+                    .get(&key)
                     .map(|skeleton| skeleton.is_dynamic)
-                    .unwrap_or(false)
+                    .unwrap_or(false),
-            }
+                None => false,
-            _ => {
+            },
-                match self.modules.get(&module_name) {
-                    Some(ref module) => {
-                        module.extensible_predicates.get(&key)
-                              .map(|skeleton| skeleton.is_dynamic)
-                              .unwrap_or(false)
-                    }
-                    None => {
-                        false
-                    }
-                }
-            }
         }
     }
 
@@ -963,8 +831,7 @@ impl IndexStore {
         IndexStore::default()
     }
 
-    pub(super)
+    pub(super) fn get_cleaner_sites(&self) -> (usize, usize) {
-    fn get_cleaner_sites(&self) -> (usize, usize) {
         let r_w_h = clause_name!("run_cleaners_with_handling");
         let r_wo_h = clause_name!("run_cleaners_without_handling");
         let iso_ext = clause_name!("iso_ext");
@@ -996,10 +863,8 @@ pub enum RefOrOwned<'a, T: 'a> {
 impl<'a, T: 'a + fmt::Debug> fmt::Debug for RefOrOwned<'a, T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            &RefOrOwned::Borrowed(ref borrowed) =>
+            &RefOrOwned::Borrowed(ref borrowed) => write!(f, "Borrowed({:?})", borrowed),
-                write!(f, "Borrowed({:?})", borrowed),
+            &RefOrOwned::Owned(ref owned) => write!(f, "Owned({:?})", owned),
-            &RefOrOwned::Owned(ref owned) =>
-                write!(f, "Owned({:?})", owned),
         }
     }
 }
@@ -1012,7 +877,9 @@ impl<'a, T> RefOrOwned<'a, T> {
         }
     }
 
-    pub fn to_owned(self) -> T where T: Clone
+    pub fn to_owned(self) -> T
+    where
+        T: Clone,
     {
         match self {
             RefOrOwned::Borrowed(item) => item.clone(),

src/machine/machine_state.rs

@@ -1,5 +1,6 @@
 use crate::prolog_parser_rebis::ast::*;
 use crate::prolog_parser_rebis::tabled_rc::*;
+use crate::prolog_parser_rebis::{clause_name, temp_v};
 
 use crate::clause_types::*;
 use crate::forms::*;
@@ -14,7 +15,9 @@ use crate::machine::stack::*;
 use crate::machine::streams::*;
 use crate::rug::Integer;
 
-use crate::downcast::Any;
+use crate::downcast::{
+    downcast, downcast_methods, downcast_methods_core, downcast_methods_std, impl_downcast, Any,
+};
 
 use crate::indexmap::IndexMap;
 
@@ -32,33 +35,26 @@ pub struct Ball {
 }
 
 impl Ball {
-    pub(super)
+    pub(super) fn new() -> Self {
-    fn new() -> Self {
         Ball {
             boundary: 0,
             stub: Heap::new(),
         }
     }
 
-    pub(super)
+    pub(super) fn reset(&mut self) {
-    fn reset(&mut self) {
         self.boundary = 0;
         self.stub.clear();
     }
 
-    pub(super)
+    pub(super) fn copy_and_align(&self, h: usize) -> Heap {
-    fn copy_and_align(&self, h: usize) -> Heap {
         let diff = self.boundary as i64 - h as i64;
         let mut stub = Heap::new();
 
         for heap_value in self.stub.iter_from(0) {
             stub.push(match heap_value {
-                &HeapCellValue::Addr(addr) => {
+                &HeapCellValue::Addr(addr) => HeapCellValue::Addr(addr - diff),
-                    HeapCellValue::Addr(addr - diff)
+                heap_value => heap_value.context_free_clone(),
-                }
-                heap_value => {
-                    heap_value.context_free_clone()
-                }
             });
         }
 
@@ -123,11 +119,7 @@ pub(super) struct CopyBallTerm<'a> {
 }
 
 impl<'a> CopyBallTerm<'a> {
-    pub(super) fn new(
+    pub(super) fn new(stack: &'a mut Stack, heap: &'a mut Heap, stub: &'a mut Heap) -> Self {
-        stack: &'a mut Stack,
-        heap: &'a mut Heap,
-        stub: &'a mut Heap,
-    ) -> Self {
         let hb = heap.h();
 
         CopyBallTerm {
@@ -182,12 +174,8 @@ impl<'a> CopierTarget for CopyBallTerm<'a> {
                 let index = h - self.heap_boundary;
                 self.stub[index].as_addr(h)
             }
-            Addr::StackCell(fr, sc) => {
+            Addr::StackCell(fr, sc) => self.stack.index_and_frame(fr)[sc],
-                self.stack.index_and_frame(fr)[sc]
+            addr => addr,
-            }
-            addr => {
-                addr
-            }
         }
     }
 
@@ -226,9 +214,7 @@ impl Index<RegType> for MachineState {
 impl IndexMut<RegType> for MachineState {
     fn index_mut(&mut self, reg: RegType) -> &mut Self::Output {
         match reg {
-            RegType::Temp(temp) => {
+            RegType::Temp(temp) => &mut self.registers[temp],
-                &mut self.registers[temp]
-            }
             RegType::Perm(perm) => {
                 let e = self.e;
 
@@ -255,15 +241,12 @@ pub(super) enum HeapPtr {
 
 impl HeapPtr {
     #[inline]
-    pub(super)
+    pub(super) fn read(&self, heap: &Heap) -> Addr {
-    fn read(&self, heap: &Heap) -> Addr {
         match self {
-            &HeapPtr::HeapCell(h) => {
+            &HeapPtr::HeapCell(h) => Addr::HeapCell(h),
-                Addr::HeapCell(h)
-            }
             &HeapPtr::PStrChar(h, n) => {
                 if let &HeapCellValue::PartialString(ref pstr, has_tail) = &heap[h] {
-                    if let Some(c) = pstr.range_from(n ..).next() {
+                    if let Some(c) = pstr.range_from(n..).next() {
                         Addr::Char(c)
                     } else if has_tail {
                         Addr::HeapCell(h + 1)
@@ -274,9 +257,7 @@ impl HeapPtr {
                     unreachable!()
                 }
             }
-            &HeapPtr::PStrLocation(h, n) => {
+            &HeapPtr::PStrLocation(h, n) => Addr::PStrLocation(h, n),
-                Addr::PStrLocation(h, n)
-            }
         }
     }
 }
@@ -313,16 +294,11 @@ pub struct MachineState {
     pub(super) last_call: bool,
     pub(crate) heap_locs: HeapVarDict,
     pub(crate) flags: MachineFlags,
-    pub(crate) at_end_of_expansion: bool
+    pub(crate) at_end_of_expansion: bool,
 }
 
 impl MachineState {
-    pub(crate)
+    pub(crate) fn read_term(&mut self, mut stream: Stream, indices: &mut IndexStore) -> CallResult {
-    fn read_term(
-        &mut self,
-        mut stream: Stream,
-        indices: &mut IndexStore,
-    ) -> CallResult {
         self.check_stream_properties(
             &mut stream,
             StreamType::Text,
@@ -342,11 +318,7 @@ impl MachineState {
         let mut orig_stream = stream.clone();
 
         loop {
-            match self.read(
+            match self.read(stream.clone(), self.atom_tbl.clone(), &indices.op_dir) {
-                stream.clone(),
-                self.atom_tbl.clone(),
-                &indices.op_dir,
-            ) {
                 Ok(term_write_result) => {
                     let term = self[temp_v!(2)];
                     self.unify(Addr::HeapCell(term_write_result.heap_loc), term);
@@ -363,7 +335,8 @@ impl MachineState {
                         let h = self.heap.h();
                         let spec = fetch_atom_op_spec(clause_name!("="), None, &indices.op_dir);
 
-                        self.heap.push(HeapCellValue::NamedStr(2, clause_name!("="), spec));
+                        self.heap
+                            .push(HeapCellValue::NamedStr(2, clause_name!("="), spec));
                         self.heap.push(HeapCellValue::Atom(var_atom, None));
                         self.heap.push(HeapCellValue::Addr(binding));
 
@@ -406,8 +379,7 @@ impl MachineState {
                     }
 
                     let vars_addr = self[temp_v!(4)];
-                    let vars_offset =
+                    let vars_offset = Addr::HeapCell(self.heap.to_list(var_list.into_iter()));
-                        Addr::HeapCell(self.heap.to_list(var_list.into_iter()));
 
                     self.unify(vars_offset, vars_addr);
 
@@ -427,7 +399,7 @@ impl MachineState {
                             self[temp_v!(2)],
                             &mut orig_stream,
                             clause_name!("read_term"),
-                            3
+                            3,
                         )?;
 
                         if orig_stream.options.eof_action == EOFAction::Reset {
@@ -448,12 +420,10 @@ impl MachineState {
         }
     }
 
-    pub(crate)
+    pub(crate) fn write_term<'a>(
-    fn write_term<'a>(
         &'a self,
         op_dir: &'a OpDir,
-    ) -> Result<Option<HCPrinter<'a, PrinterOutputter>>, MachineStub>
+    ) -> Result<Option<HCPrinter<'a, PrinterOutputter>>, MachineStub> {
-    {
         let ignore_ops = self.store(self.deref(self[temp_v!(3)]));
         let numbervars = self.store(self.deref(self[temp_v!(4)]));
         let quoted = self.store(self.deref(self[temp_v!(5)]));
@@ -462,7 +432,7 @@ impl MachineState {
         let mut printer = HCPrinter::new(&self, op_dir, PrinterOutputter::new());
 
         if let &Addr::Con(h) = &ignore_ops {
-	        if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
+            if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
                 printer.ignore_ops = name.as_str() == "true";
             } else {
                 unreachable!()
@@ -470,7 +440,7 @@ impl MachineState {
         }
 
         if let &Addr::Con(h) = &numbervars {
-	        if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
+            if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
                 printer.numbervars = name.as_str() == "true";
             } else {
                 unreachable!()
@@ -478,7 +448,7 @@ impl MachineState {
         }
 
         if let &Addr::Con(h) = &quoted {
-	        if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
+            if let HeapCellValue::Atom(ref name, _) = &self.heap[h] {
                 printer.quoted = name.as_str() == "true";
             } else {
                 unreachable!()
@@ -514,9 +484,7 @@ impl MachineState {
                 for addr in addrs {
                     match addr {
                         Addr::Str(s) => match &self.heap[s] {
-                            &HeapCellValue::NamedStr(2, ref name, _)
+                            &HeapCellValue::NamedStr(2, ref name, _) if name.as_str() == "=" => {
-                                if name.as_str() == "=" =>
-                            {
                                 let atom = self.heap[s + 1].as_addr(s + 1);
                                 let var = self.heap[s + 2].as_addr(s + 2);
 
@@ -540,11 +508,9 @@ impl MachineState {
 
                                 var_names.insert(var, atom);
                             }
-                            _ => {
+                            _ => {}
-                            }
                         },
-                        _ => {
+                        _ => {}
-                        }
                     }
                 }
 
@@ -558,8 +524,7 @@ impl MachineState {
         Ok(Some(printer))
     }
 
-    pub(super)
+    pub(super) fn throw_undefined_error(&mut self, name: ClauseName, arity: usize) -> MachineStub {
-    fn throw_undefined_error(&mut self, name: ClauseName, arity: usize) -> MachineStub {
         let stub = MachineError::functor_stub(name.clone(), arity);
         let h = self.heap.h();
         let key = ExistenceError::Procedure(name, arity);
@@ -568,13 +533,11 @@ impl MachineState {
     }
 
     #[inline]
-    pub(crate)
+    pub(crate) fn heap_pstr_iter<'a>(&'a self, focus: Addr) -> HeapPStrIter<'a> {
-    fn heap_pstr_iter<'a>(&'a self, focus: Addr) -> HeapPStrIter<'a> {
         HeapPStrIter::new(self, focus)
     }
 
-    pub(super)
+    pub(super) fn try_char_list(&self, addrs: Vec<Addr>) -> Result<String, MachineError> {
-    fn try_char_list(&self, addrs: Vec<Addr>) -> Result<String, MachineError> {
         let mut chars = String::new();
         let mut iter = addrs.iter();
 
@@ -594,55 +557,46 @@ impl MachineState {
                         }
                     }
                 }
-                _ => {
+                _ => {}
-                }
             };
 
             let h = self.heap.h();
 
-            return Err(
+            return Err(MachineError::type_error(h, ValidType::Character, addr));
-                MachineError::type_error(h, ValidType::Character, addr)
-            );
         }
 
         Ok(chars)
     }
 
-    pub(super)
+    pub(super) fn read_predicate_key(&self, name: Addr, arity: Addr) -> (ClauseName, usize) {
-    fn read_predicate_key(&self, name: Addr, arity: Addr) -> (ClauseName, usize) {
         let predicate_name = atom_from!(self, self.store(self.deref(name)));
         let arity = self.store(self.deref(arity));
 
-        let arity =
+        let arity = match Number::try_from((arity, &self.heap)) {
-            match Number::try_from((arity, &self.heap)) {
+            Ok(Number::Integer(n)) if &*n >= &0 && &*n <= &MAX_ARITY => n.to_usize().unwrap(),
-                Ok(Number::Integer(n)) if &*n >= &0 && &*n <= &MAX_ARITY =>
+            Ok(Number::Fixnum(n)) if n >= 0 && n <= MAX_ARITY as isize => {
-                    n.to_usize().unwrap(),
+                usize::try_from(n).unwrap()
-                Ok(Number::Fixnum(n)) if n >= 0 && n <= MAX_ARITY as isize =>
+            }
-                    usize::try_from(n).unwrap(),
+            _ => unreachable!(),
-                _ =>
+        };
-                    unreachable!()
-            };
 
         (predicate_name, arity)
     }
 
-    pub(super)
+    pub(super) fn call_at_index(&mut self, arity: usize, p: LocalCodePtr) {
-    fn call_at_index(&mut self, arity: usize, p: LocalCodePtr) {
         self.cp.assign_if_local(self.p.clone() + 1);
         self.num_of_args = arity;
         self.b0 = self.b;
         self.p = CodePtr::Local(p);
     }
 
-    pub(super)
+    pub(super) fn execute_at_index(&mut self, arity: usize, p: LocalCodePtr) {
-    fn execute_at_index(&mut self, arity: usize, p: LocalCodePtr) {
         self.num_of_args = arity;
         self.b0 = self.b;
         self.p = CodePtr::Local(p);
     }
 
-    pub(super)
+    pub(super) fn module_lookup(
-    fn module_lookup(
         &mut self,
         indices: &IndexStore,
         call_policy: &mut Box<dyn CallPolicy>,
@@ -687,10 +641,15 @@ pub(crate) type CallResult = Result<(), Vec<HeapCellValue>>;
 pub(crate) trait CallPolicy: Any + fmt::Debug {
     fn retry_me_else(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
         let b = machine_st.b;
-        let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
+        let n = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .univ_prelude
+            .num_cells;
 
-        for i in 1 .. n + 1 {
+        for i in 1..n + 1 {
-            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
+            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i - 1];
         }
 
         machine_st.num_of_args = n;
@@ -706,17 +665,24 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
         machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
 
         machine_st.trail.truncate(machine_st.tr);
-        machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
+        machine_st
+            .heap
+            .truncate(machine_st.stack.index_or_frame(b).prelude.h);
 
-        let attr_var_init_queue_b =
+        let attr_var_init_queue_b = machine_st
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
+            .stack
-        let attr_var_init_bindings_b =
+            .index_or_frame(b)
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
+            .prelude
+            .attr_var_init_queue_b;
+        let attr_var_init_bindings_b = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .attr_var_init_bindings_b;
 
-        machine_st.attr_var_init.backtrack(
+        machine_st
-            attr_var_init_queue_b,
+            .attr_var_init
-            attr_var_init_bindings_b,
+            .backtrack(attr_var_init_queue_b, attr_var_init_bindings_b);
-        );
 
         machine_st.hb = machine_st.heap.h();
         machine_st.p += 1;
@@ -726,10 +692,15 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
 
     fn retry(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
         let b = machine_st.b;
-        let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
+        let n = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .univ_prelude
+            .num_cells;
 
-        for i in 1 .. n + 1 {
+        for i in 1..n + 1 {
-            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
+            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i - 1];
         }
 
         machine_st.num_of_args = n;
@@ -745,14 +716,24 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
         machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
 
         machine_st.trail.truncate(machine_st.tr);
-        machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
+        machine_st
+            .heap
+            .truncate(machine_st.stack.index_or_frame(b).prelude.h);
 
-        let attr_var_init_queue_b =
+        let attr_var_init_queue_b = machine_st
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
+            .stack
-        let attr_var_init_bindings_b =
+            .index_or_frame(b)
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
+            .prelude
+            .attr_var_init_queue_b;
+        let attr_var_init_bindings_b = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .attr_var_init_bindings_b;
 
-        machine_st.attr_var_init.backtrack(attr_var_init_queue_b, attr_var_init_bindings_b);
+        machine_st
+            .attr_var_init
+            .backtrack(attr_var_init_queue_b, attr_var_init_bindings_b);
 
         machine_st.hb = machine_st.heap.h();
         machine_st.p = CodePtr::Local(dir_entry!(machine_st.p.local().abs_loc() + offset));
@@ -762,10 +743,15 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
 
     fn trust(&mut self, machine_st: &mut MachineState, offset: usize) -> CallResult {
         let b = machine_st.b;
-        let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
+        let n = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .univ_prelude
+            .num_cells;
 
-        for i in 1 .. n + 1 {
+        for i in 1..n + 1 {
-            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
+            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i - 1];
         }
 
         machine_st.num_of_args = n;
@@ -779,17 +765,24 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
         machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
 
         machine_st.trail.truncate(machine_st.tr);
-        machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
+        machine_st
+            .heap
+            .truncate(machine_st.stack.index_or_frame(b).prelude.h);
 
-        let attr_var_init_queue_b =
+        let attr_var_init_queue_b = machine_st
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
+            .stack
-        let attr_var_init_bindings_b =
+            .index_or_frame(b)
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
+            .prelude
+            .attr_var_init_queue_b;
+        let attr_var_init_bindings_b = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .attr_var_init_bindings_b;
 
-        machine_st.attr_var_init.backtrack(
+        machine_st
-            attr_var_init_queue_b,
+            .attr_var_init
-            attr_var_init_bindings_b,
+            .backtrack(attr_var_init_queue_b, attr_var_init_bindings_b);
-        );
 
         machine_st.b = machine_st.stack.index_or_frame(b).prelude.b;
         machine_st.stack.truncate(b);
@@ -802,10 +795,15 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
 
     fn trust_me(&mut self, machine_st: &mut MachineState) -> CallResult {
         let b = machine_st.b;
-        let n = machine_st.stack.index_or_frame(b).prelude.univ_prelude.num_cells;
+        let n = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .univ_prelude
+            .num_cells;
 
-        for i in 1 .. n + 1 {
+        for i in 1..n + 1 {
-            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i-1];
+            machine_st.registers[i] = machine_st.stack.index_or_frame(b)[i - 1];
         }
 
         machine_st.num_of_args = n;
@@ -819,17 +817,24 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
         machine_st.tr = machine_st.stack.index_or_frame(b).prelude.tr;
 
         machine_st.trail.truncate(machine_st.tr);
-        machine_st.heap.truncate(machine_st.stack.index_or_frame(b).prelude.h);
+        machine_st
+            .heap
+            .truncate(machine_st.stack.index_or_frame(b).prelude.h);
 
-        let attr_var_init_queue_b =
+        let attr_var_init_queue_b = machine_st
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_queue_b;
+            .stack
-        let attr_var_init_bindings_b =
+            .index_or_frame(b)
-            machine_st.stack.index_or_frame(b).prelude.attr_var_init_bindings_b;
+            .prelude
+            .attr_var_init_queue_b;
+        let attr_var_init_bindings_b = machine_st
+            .stack
+            .index_or_frame(b)
+            .prelude
+            .attr_var_init_bindings_b;
 
-        machine_st.attr_var_init.backtrack(
+        machine_st
-            attr_var_init_queue_b,
+            .attr_var_init
-            attr_var_init_bindings_b,
+            .backtrack(attr_var_init_queue_b, attr_var_init_bindings_b);
-        );
 
         machine_st.b = machine_st.stack.index_or_frame(b).prelude.b;
         machine_st.stack.truncate(b);
@@ -928,13 +933,13 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
                     Addr::Con(h) if machine_st.heap.atom_at(h) => {
                         if let HeapCellValue::Atom(ref atom, _) = &machine_st.heap[h] {
                             match atom.as_str() {
-                                ">" | "<" | "=" => {
+                                ">" | "<" | "=" => {}
-                                }
                                 _ => {
                                     let stub =
                                         MachineError::functor_stub(clause_name!("compare"), 3);
 
-                                    let err = MachineError::domain_error(DomainErrorType::Order, a1);
+                                    let err =
+                                        MachineError::domain_error(DomainErrorType::Order, a1);
                                     return Err(machine_st.error_form(err, stub));
                                 }
                             }
@@ -948,8 +953,7 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
                         let err = MachineError::type_error(h, ValidType::Atom, a1);
                         return Err(machine_st.error_form(err, stub));
                     }
-                    _ => {
+                    _ => {}
-                    }
                 }
 
                 let atom = match machine_st.compare_term_test(&a2, &a3) {
@@ -998,9 +1002,7 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
                         let addr = machine_st[temp_v!(1)];
                         let eof = clause_name!("end_of_file".to_string(), machine_st.atom_tbl);
 
-                        let atom = machine_st.heap.to_unifiable(
+                        let atom = machine_st.heap.to_unifiable(HeapCellValue::Atom(eof, None));
-                            HeapCellValue::Atom(eof, None)
-                        );
 
                         machine_st.unify(addr, atom);
                     }
@@ -1056,7 +1058,9 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
                 let mut list = machine_st.try_from_list(temp_v!(1), stub)?;
 
                 list.sort_unstable_by(|a1, a2| {
-                    machine_st.compare_term_test(a1, a2).unwrap_or(Ordering::Less)
+                    machine_st
+                        .compare_term_test(a1, a2)
+                        .unwrap_or(Ordering::Less)
                 });
 
                 machine_st.term_dedup(&mut list);
@@ -1081,7 +1085,9 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
                 }
 
                 key_pairs.sort_by(|a1, a2| {
-                    machine_st.compare_term_test(&a1.0, &a2.0).unwrap_or(Ordering::Less)
+                    machine_st
+                        .compare_term_test(&a1.0, &a2.0)
+                        .unwrap_or(Ordering::Less)
                 });
 
                 let key_pairs = key_pairs.into_iter().map(|kp| kp.1);
@@ -1155,11 +1161,7 @@ pub(crate) trait CallPolicy: Any + fmt::Debug {
                 let stub = MachineError::functor_stub(clause_name!("call"), arity + 1);
 
                 return Err(machine_st.error_form(
-                    MachineError::type_error(
+                    MachineError::type_error(machine_st.heap.h(), ValidType::Callable, name),
-                        machine_st.heap.h(),
-                        ValidType::Callable,
-                        name
-                    ),
                     stub,
                 ));
             }
@@ -1200,7 +1202,8 @@ impl CallPolicy for CWILCallPolicy {
         arity: usize,
         idx: &CodeIndex,
     ) -> CallResult {
-        self.prev_policy.context_call(machine_st, name, arity, idx)?;//, indices)?;
+        self.prev_policy
+            .context_call(machine_st, name, arity, idx)?; //, indices)?;
         self.increment(machine_st)
     }
 
@@ -1239,7 +1242,7 @@ impl CallPolicy for CWILCallPolicy {
             code_dir,
             op_dir,
             current_input_stream,
-            current_output_stream
+            current_output_stream,
         )?;
 
         self.increment(machine_st)
@@ -1283,8 +1286,7 @@ pub(crate) struct CWILCallPolicy {
 }
 
 impl CWILCallPolicy {
-    pub(crate)
+    pub(crate) fn new_in_place(policy: &mut Box<dyn CallPolicy>) {
-    fn new_in_place(policy: &mut Box<dyn CallPolicy>) {
         let mut prev_policy: Box<dyn CallPolicy> = Box::new(DefaultCallPolicy {});
         mem::swap(&mut prev_policy, policy);
 
@@ -1319,8 +1321,7 @@ impl CWILCallPolicy {
         Ok(())
     }
 
-    pub(crate)
+    pub(crate) fn add_limit(&mut self, mut limit: Integer, b: usize) -> &Integer {
-    fn add_limit(&mut self, mut limit: Integer, b: usize) -> &Integer {
         limit += &self.count;
 
         match self.limits.last().cloned() {
@@ -1331,8 +1332,7 @@ impl CWILCallPolicy {
         &self.count
     }
 
-    pub(crate)
+    pub(crate) fn remove_limit(&mut self, b: usize) -> &Integer {
-    fn remove_limit(&mut self, b: usize) -> &Integer {
         if let Some((_, bp)) = self.limits.last().cloned() {
             if bp == b {
                 self.limits.pop();
@@ -1342,13 +1342,11 @@ impl CWILCallPolicy {
         &self.count
     }
 
-    pub(crate)
+    pub(crate) fn is_empty(&self) -> bool {
-    fn is_empty(&self) -> bool {
         self.limits.is_empty()
     }
 
-    pub(crate)
+    pub(crate) fn into_inner(&mut self) -> Box<dyn CallPolicy> {
-    fn into_inner(&mut self) -> Box<dyn CallPolicy> {
         let mut new_inner: Box<dyn CallPolicy> = Box::new(DefaultCallPolicy {});
         mem::swap(&mut self.prev_policy, &mut new_inner);
         new_inner

src/machine/mod.rs

@@ -1,5 +1,8 @@
 use crate::prolog_parser_rebis::ast::*;
 use crate::prolog_parser_rebis::tabled_rc::*;
+use crate::prolog_parser_rebis::{clause_name, temp_v};
+
+use crate::lazy_static::lazy_static;
 
 use crate::clause_types::*;
 use crate::forms::*;
@@ -34,8 +37,8 @@ mod machine_state_impl;
 mod system_calls;
 
 //use crate::machine::attributed_variables::*;
-use crate::machine::compile::*;
 use crate::machine::code_repo::*;
+use crate::machine::compile::*;
 // use crate::machine::loader::*;
 use crate::machine::machine_errors::*;
 use crate::machine::machine_indices::*;
@@ -45,6 +48,7 @@ use crate::machine::streams::*;
 use crate::indexmap::IndexMap;
 
 //use std::convert::TryFrom;
+use prolog_parser_rebis::ast::ClauseName;
 use std::fs::File;
 use std::mem;
 use std::path::PathBuf;
@@ -162,18 +166,13 @@ impl Machine {
     }
 
     fn load_file(&mut self, path: String, stream: Stream) {
-        self.machine_st[temp_v!(1)] = Addr::Stream(
+        self.machine_st[temp_v!(1)] =
-            self.machine_st.heap.push(HeapCellValue::Stream(
+            Addr::Stream(self.machine_st.heap.push(HeapCellValue::Stream(stream)));
-                stream,
-            ))
-        );
 
-        self.machine_st[temp_v!(2)] = Addr::Con(
+        self.machine_st[temp_v!(2)] = Addr::Con(self.machine_st.heap.push(HeapCellValue::Atom(
-            self.machine_st.heap.push(HeapCellValue::Atom(
+            clause_name!(path, self.machine_st.atom_tbl),
-                clause_name!(path, self.machine_st.atom_tbl),
+            None,
-                None,
+        )));
-            ))
-        );
 
         self.run_module_predicate(clause_name!("loader"), (clause_name!("file_load"), 2));
     }
@@ -206,11 +205,9 @@ impl Machine {
         bootstrapping_compile(
             Stream::from(include_str!("attributed_variables.pl")),
             self,
-            ListingSource::from_file_and_path(
+            ListingSource::from_file_and_path(clause_name!("attributed_variables"), path_buf),
-                clause_name!("attributed_variables"),
+        )
-                path_buf,
+        .unwrap();
-            ),
-        ).unwrap();
 
         let mut path_buf = current_dir();
         path_buf.push("machine/project_attributes.pl");
@@ -218,11 +215,9 @@ impl Machine {
         bootstrapping_compile(
             Stream::from(include_str!("project_attributes.pl")),
             self,
-            ListingSource::from_file_and_path(
+            ListingSource::from_file_and_path(clause_name!("project_attributes"), path_buf),
-                clause_name!("project_attributes"),
+        )
-                path_buf,
+        .unwrap();
-            ),
-        ).unwrap();
 
         if let Some(module) = self.indices.modules.get(&clause_name!("$atts")) {
             if let Some(code_index) = module.code_dir.get(&(clause_name!("driver"), 2)) {
@@ -255,12 +250,13 @@ impl Machine {
 
     fn configure_modules(&mut self) {
         fn update_call_n_indices(loader: &Module, target_module: &mut Module) {
-            for arity in 1 .. 66 {
+            for arity in 1..66 {
                 let key = (clause_name!("call"), arity);
 
                 match loader.code_dir.get(&key) {
                     Some(src_code_index) => {
-                        let target_code_index = target_module.code_dir
+                        let target_code_index = target_module
+                            .code_dir
                             .entry(key.clone())
                             .or_insert_with(|| CodeIndex::new(IndexPtr::Undefined));
 
@@ -289,10 +285,11 @@ impl Machine {
                     builtins.module_decl.exports.push(export.clone());
                 }
 
-                for arity in 10 .. 66 {
+                for arity in 10..66 {
-                    builtins.module_decl.exports.push(
+                    builtins
-                        ModuleExport::PredicateKey((clause_name!("call"), arity)),
+                        .module_decl
-                    );
+                        .exports
+                        .push(ModuleExport::PredicateKey((clause_name!("call"), arity)));
                 }
             }
 
@@ -306,8 +303,7 @@ impl Machine {
         }
     }
 
-    pub fn new(user_input: Stream, user_output: Stream) -> Self
+    pub fn new(user_input: Stream, user_output: Stream) -> Self {
-    {
         use crate::ref_thread_local::RefThreadLocal;
 
         let mut wam = Machine {
@@ -333,16 +329,15 @@ impl Machine {
                 clause_name!("ops_and_meta_predicates.pl"),
                 lib_path.clone(),
             ),
-        ).unwrap();
+        )
+        .unwrap();
 
         bootstrapping_compile(
             Stream::from(LIBRARIES.borrow()["builtins"]),
             &mut wam,
-            ListingSource::from_file_and_path(
+            ListingSource::from_file_and_path(clause_name!("builtins.pl"), lib_path.clone()),
-                clause_name!("builtins.pl"),
+        )
-                lib_path.clone(),
+        .unwrap();
-            ),
-        ).unwrap();
 
         if let Some(builtins) = wam.indices.modules.get(&clause_name!("builtins")) {
             load_module(
@@ -361,11 +356,9 @@ impl Machine {
         bootstrapping_compile(
             Stream::from(include_str!("../loader.pl")),
             &mut wam,
-            ListingSource::from_file_and_path(
+            ListingSource::from_file_and_path(clause_name!("loader.pl"), lib_path.clone()),
-                clause_name!("loader.pl"),
+        )
-                lib_path.clone(),
+        .unwrap();
-            ),
-        ).unwrap();
 
         wam.configure_modules();
 
@@ -391,25 +384,19 @@ impl Machine {
     pub fn configure_streams(&mut self) {
         self.user_input.options.alias = Some(clause_name!("user_input"));
 
-        self.indices.stream_aliases.insert(
+        self.indices
-            clause_name!("user_input"),
+            .stream_aliases
-            self.user_input.clone(),
+            .insert(clause_name!("user_input"), self.user_input.clone());
-        );
 
-        self.indices.streams.insert(
+        self.indices.streams.insert(self.user_input.clone());
-            self.user_input.clone()
-        );
 
         self.user_output.options.alias = Some(clause_name!("user_output"));
 
-        self.indices.stream_aliases.insert(
+        self.indices
-            clause_name!("user_output"),
+            .stream_aliases
-            self.user_output.clone(),
+            .insert(clause_name!("user_output"), self.user_output.clone());
-        );
 
-        self.indices.streams.insert(
+        self.indices.streams.insert(self.user_output.clone());
-            self.user_output.clone()
-        );
     }
 
     fn throw_session_error(&mut self, err: SessionError, key: PredicateKey) {
@@ -508,8 +495,7 @@ impl Machine {
         self.machine_st.p = CodePtr::Local(p);
     }
 
-    pub(super)
+    pub(super) fn run_query(&mut self) {
-    fn run_query(&mut self) {
         while !self.machine_st.p.is_halt() {
             self.machine_st.query_stepper(
                 &mut self.indices,
@@ -546,26 +532,22 @@ impl MachineState {
         user_output: &mut Stream,
     ) {
         match instr {
-            &Line::Arithmetic(ref arith_instr) => {
+            &Line::Arithmetic(ref arith_instr) => self.execute_arith_instr(arith_instr),
-                self.execute_arith_instr(arith_instr)
-            }
             &Line::Choice(ref choice_instr) => {
                 self.execute_choice_instr(choice_instr, &mut policies.call_policy)
             }
             &Line::Cut(ref cut_instr) => {
                 self.execute_cut_instr(cut_instr, &mut policies.cut_policy)
             }
-            &Line::Control(ref control_instr) => {
+            &Line::Control(ref control_instr) => self.execute_ctrl_instr(
-                self.execute_ctrl_instr(
+                indices,
-                    indices,
+                code_repo,
-                    code_repo,
+                &mut policies.call_policy,
-                    &mut policies.call_policy,
+                &mut policies.cut_policy,
-                    &mut policies.cut_policy,
+                user_input,
-                    user_input,
+                user_output,
-                    user_output,
+                control_instr,
-                    control_instr,
+            ),
-                )
-            }
             &Line::Fact(ref fact_instr) => {
                 self.execute_fact_instr(&fact_instr);
                 self.p += 1;
@@ -617,15 +599,13 @@ impl MachineState {
 
     fn check_machine_index(&mut self, code_repo: &CodeRepo) -> bool {
         match self.p {
-            CodePtr::Local(LocalCodePtr::DirEntry(p)) |
+            CodePtr::Local(LocalCodePtr::DirEntry(p))
-            CodePtr::Local(LocalCodePtr::IndexingBuf(p, ..))
+            | CodePtr::Local(LocalCodePtr::IndexingBuf(p, ..))
-                if p < code_repo.code.len() => {
+                if p < code_repo.code.len() => {}
-                }
             CodePtr::Local(LocalCodePtr::Halt) | CodePtr::REPL(..) => {
                 return false;
             }
-            _ => {
+            _ => {}
-            }
         }
 
         true
@@ -689,13 +669,7 @@ impl MachineState {
         user_output: &mut Stream,
     ) {
         loop {
-            self.execute_instr(
+            self.execute_instr(indices, policies, code_repo, user_input, user_output);
-                indices,
-                policies,
-                code_repo,
-                user_input,
-                user_output,
-            );
 
             if self.fail {
                 self.backtrack();

src/machine/preprocessor.rs

@@ -1,11 +1,12 @@
 use crate::prolog_parser_rebis::ast::*;
 use crate::prolog_parser_rebis::tabled_rc::*;
+use crate::prolog_parser_rebis::{atom, clause_name, rc_atom};
 
 use crate::forms::*;
 use crate::iterators::*;
-use crate::machine::*;
 use crate::machine::load_state::*;
 use crate::machine::machine_errors::*;
+use crate::machine::*;
 
 use crate::indexmap::IndexSet;
 
@@ -85,27 +86,24 @@ fn setup_op_decl(
     to_op_decl(prec, spec.as_str(), name)
 }
 
-fn setup_predicate_indicator(term: &mut Term) -> Result<PredicateKey, CompilationError>
+fn setup_predicate_indicator(term: &mut Term) -> Result<PredicateKey, CompilationError> {
-{
     match term {
         Term::Clause(_, ref slash, ref mut terms, Some(_))
             if (slash.as_str() == "/" || slash.as_str() == "//") && terms.len() == 2 =>
         {
             let arity = *terms.pop().unwrap();
-            let name  = *terms.pop().unwrap();
+            let name = *terms.pop().unwrap();
 
             let arity = arity
                 .to_constant()
-                .and_then(|c| {
+                .and_then(|c| match c {
-                    match c {
+                    Constant::Integer(n) => n.to_usize(),
-                        Constant::Integer(n) => n.to_usize(),
+                    Constant::Fixnum(n) => usize::try_from(n).ok(),
-                        Constant::Fixnum(n) => usize::try_from(n).ok(),
+                    _ => None,
-                        _ => None
-                    }
                 })
                 .ok_or(CompilationError::InvalidModuleExport)?;
 
-            let name  = name
+            let name = name
                 .to_constant()
                 .and_then(|c| c.to_atom())
                 .ok_or(CompilationError::InvalidModuleExport)?;
@@ -116,9 +114,7 @@ fn setup_predicate_indicator(term: &mut Term) -> Result<PredicateKey, Compilatio
                 Ok((name, arity + 2))
             }
         }
-        _ => {
+        _ => Err(CompilationError::InvalidModuleExport),
-            Err(CompilationError::InvalidModuleExport)
-        }
     }
 }
 
@@ -155,10 +151,7 @@ fn setup_module_export(
         .or_else(|_| {
             if let Term::Clause(_, name, terms, _) = term {
                 if terms.len() == 3 && name.as_str() == "op" {
-                    Ok(ModuleExport::OpDecl(setup_op_decl(
+                    Ok(ModuleExport::OpDecl(setup_op_decl(terms, atom_tbl)?))
-                        terms,
-                        atom_tbl
-                    )?))
                 } else {
                     Err(CompilationError::InvalidModuleDecl)
                 }
@@ -168,8 +161,7 @@ fn setup_module_export(
         })
 }
 
-pub(super)
+pub(super) fn setup_module_export_list(
-fn setup_module_export_list(
     mut export_list: Term,
     atom_tbl: TabledData<Atom>,
 ) -> Result<Vec<ModuleExport>, CompilationError> {
@@ -218,8 +210,7 @@ fn setup_use_module_decl(mut terms: Vec<Box<Term>>) -> Result<ModuleSource, Comp
                 .map(|c| ModuleSource::Library(c))
                 .ok_or(CompilationError::InvalidUseModuleDecl)
         }
-        Term::Constant(_, Constant::Atom(ref name, _)) =>
+        Term::Constant(_, Constant::Atom(ref name, _)) => Ok(ModuleSource::File(name.clone())),
-            Ok(ModuleSource::File(name.clone())),
         _ => Err(CompilationError::InvalidUseModuleDecl),
     }
 }
@@ -271,12 +262,8 @@ fn setup_qualified_import(
                 .map(|c| ModuleSource::Library(c))
                 .ok_or(CompilationError::InvalidUseModuleDecl)
         }
-        Term::Constant(_, Constant::Atom(ref name, _)) => {
+        Term::Constant(_, Constant::Atom(ref name, _)) => Ok(ModuleSource::File(name.clone())),
-            Ok(ModuleSource::File(name.clone()))
+        _ => Err(CompilationError::InvalidUseModuleDecl),
-        }
-        _ => {
-            Err(CompilationError::InvalidUseModuleDecl)
-        }
     }?;
 
     let mut exports = IndexSet::new();
@@ -334,8 +321,7 @@ fn setup_qualified_import(
 fn setup_meta_predicate<'a>(
     mut terms: Vec<Box<Term>>,
     load_state: &LoadState<'a>,
-) -> Result<(ClauseName, ClauseName, Vec<MetaSpec>), CompilationError>
+) -> Result<(ClauseName, ClauseName, Vec<MetaSpec>), CompilationError> {
-{
     fn get_name_and_meta_specs(
         name: ClauseName,
         terms: &mut [Box<Term>],
@@ -345,26 +331,23 @@ fn setup_meta_predicate<'a>(
         for meta_spec in terms.into_iter() {
             match &**meta_spec {
                 Term::Constant(_, Constant::Atom(meta_spec, _)) => {
-                    let meta_spec =
+                    let meta_spec = match meta_spec.as_str() {
-                        match meta_spec.as_str() {
+                        "+" => MetaSpec::Plus,
-                            "+" => MetaSpec::Plus,
+                        "-" => MetaSpec::Minus,
-                            "-" => MetaSpec::Minus,
+                        "?" => MetaSpec::Either,
-                            "?" => MetaSpec::Either,
+                        _ => return Err(CompilationError::InvalidMetaPredicateDecl),
-                            _   => return Err(CompilationError::InvalidMetaPredicateDecl),
+                    };
-                        };
 
                     meta_specs.push(meta_spec);
                 }
-                Term::Constant(_, Constant::Fixnum(n)) => {
+                Term::Constant(_, Constant::Fixnum(n)) => match usize::try_from(*n) {
-                    match usize::try_from(*n) {
+                    Ok(n) if n <= MAX_ARITY => {
-                        Ok(n) if n <= MAX_ARITY => {
+                        meta_specs.push(MetaSpec::RequiresExpansionWithArgument(n));
-                            meta_specs.push(MetaSpec::RequiresExpansionWithArgument(n));
-                        }
-                        _ => {
-                            return Err(CompilationError::InvalidMetaPredicateDecl);
-                        }
                     }
-                }
+                    _ => {
+                        return Err(CompilationError::InvalidMetaPredicateDecl);
+                    }
+                },
                 _ => {
                     return Err(CompilationError::InvalidMetaPredicateDecl);
                 }
@@ -375,42 +358,35 @@ fn setup_meta_predicate<'a>(
     }
 
     match *terms.pop().unwrap() {
-        Term::Clause(_, name, mut terms, _)
+        Term::Clause(_, name, mut terms, _) if name.as_str() == ":" && terms.len() == 2 => {
-            if name.as_str() == ":" && terms.len() == 2 => {
+            let spec = *terms.pop().unwrap();
-                let spec = *terms.pop().unwrap();
+            let module_name = *terms.pop().unwrap();
-                let module_name = *terms.pop().unwrap();
 
-                match module_name {
+            match module_name {
-                    Term::Constant(_, Constant::Atom(module_name, _)) => {
+                Term::Constant(_, Constant::Atom(module_name, _)) => match spec {
-                        match spec {
+                    Term::Clause(_, name, mut terms, _) => {
-                            Term::Clause(_, name, mut terms, _) => {
+                        let (name, meta_specs) = get_name_and_meta_specs(name, &mut terms)?;
-                                let (name, meta_specs) =
-                                    get_name_and_meta_specs(name, &mut terms)?;
 
-                                Ok((module_name, name, meta_specs))
+                        Ok((module_name, name, meta_specs))
-                            }
-                            _ => {
-                                Err(CompilationError::InvalidMetaPredicateDecl)
-                            }
-                        }
                     }
-                    _ => {
+                    _ => Err(CompilationError::InvalidMetaPredicateDecl),
-                        Err(CompilationError::InvalidMetaPredicateDecl)
+                },
-                    }
+                _ => Err(CompilationError::InvalidMetaPredicateDecl),
-                }
             }
+        }
         Term::Clause(_, name, mut terms, _) => {
             let (name, meta_specs) = get_name_and_meta_specs(name, &mut terms)?;
-            Ok((load_state.compilation_target.module_name(), name, meta_specs))
+            Ok((
-        }
+                load_state.compilation_target.module_name(),
-        _ => {
+                name,
-            Err(CompilationError::InvalidMetaPredicateDecl)
+                meta_specs,
+            ))
         }
+        _ => Err(CompilationError::InvalidMetaPredicateDecl),
     }
 }
 
-fn merge_clauses(tls: &mut VecDeque<TopLevel>) -> Result<TopLevel, CompilationError>
+fn merge_clauses(tls: &mut VecDeque<TopLevel>) -> Result<TopLevel, CompilationError> {
-{
     let mut clauses = vec![];
 
     while let Some(tl) = tls.pop_front() {
@@ -432,9 +408,7 @@ fn merge_clauses(tls: &mut VecDeque<TopLevel>) -> Result<TopLevel, CompilationEr
                 let clause = PredicateClause::Rule(rule);
                 clauses.push(clause);
             }
-            TopLevel::Predicate(predicate) => {
+            TopLevel::Predicate(predicate) => clauses.extend(predicate.into_iter()),
-                clauses.extend(predicate.into_iter())
-            }
             _ => {
                 tls.push_front(tl);
                 break;
@@ -506,8 +480,8 @@ fn check_for_internal_if_then(terms: &mut Vec<Term>) {
 
         conq_terms.push_front(Term::Constant(
             Cell::default(),
-            Constant::Atom(clause_name!("blocked_!"), None))
+            Constant::Atom(clause_name!("blocked_!"), None),
-        );
+        ));
 
         while let Some(term) = pre_cut_terms.pop_back() {
             conq_terms.push_front(term);
@@ -531,38 +505,29 @@ fn setup_declaration<'a>(
     let atom_tbl = load_state.wam.machine_st.atom_tbl.clone();
 
     match term {
-        Term::Clause(_, name, mut terms, _) =>
+        Term::Clause(_, name, mut terms, _) => match (name.as_str(), terms.len()) {
-            match (name.as_str(), terms.len()) {
+            ("dynamic", 1) => {
-                ("dynamic", 1) => {
+                let (name, arity) = setup_predicate_indicator(&mut *terms.pop().unwrap())?;
-		            let (name, arity) = setup_predicate_indicator(&mut *terms.pop().unwrap())?;
+                Ok(Declaration::Dynamic(name, arity))
-		            Ok(Declaration::Dynamic(name, arity))
+            }
-		        }
+            ("module", 2) => Ok(Declaration::Module(setup_module_decl(terms, atom_tbl)?)),
-                ("module", 2) =>
+            ("op", 3) => Ok(Declaration::Op(setup_op_decl(terms, atom_tbl)?)),
-                    Ok(Declaration::Module(setup_module_decl(terms, atom_tbl)?)),
+            ("non_counted_backtracking", 1) => {
-                ("op", 3) =>
+                let (name, arity) = setup_predicate_indicator(&mut *terms.pop().unwrap())?;
-                    Ok(Declaration::Op(setup_op_decl(terms, atom_tbl)?)),
+                Ok(Declaration::NonCountedBacktracking(name, arity))
-                ("non_counted_backtracking", 1) => {
+            }
-                    let (name, arity) = setup_predicate_indicator(&mut *terms.pop().unwrap())?;
+            ("use_module", 1) => Ok(Declaration::UseModule(setup_use_module_decl(terms)?)),
-                    Ok(Declaration::NonCountedBacktracking(name, arity))
+            ("use_module", 2) => {
-                }
+                let (name, exports) = setup_qualified_import(terms, atom_tbl)?;
-                ("use_module", 1) => {
+                Ok(Declaration::UseQualifiedModule(name, exports))
-                    Ok(Declaration::UseModule(setup_use_module_decl(terms)?))
+            }
-                }
+            ("meta_predicate", 1) => {
-                ("use_module", 2) => {
+                let (module_name, name, meta_specs) = setup_meta_predicate(terms, load_state)?;
-                    let (name, exports) = setup_qualified_import(terms, atom_tbl)?;
+                Ok(Declaration::MetaPredicate(module_name, name, meta_specs))
-                    Ok(Declaration::UseQualifiedModule(name, exports))
+            }
-                }
+            _ => Err(CompilationError::InconsistentEntry),
-                ("meta_predicate", 1) => {
+        },
-                    let (module_name, name, meta_specs) = setup_meta_predicate(terms, load_state)?;
+        _ => Err(CompilationError::InconsistentEntry),
-                    Ok(Declaration::MetaPredicate(module_name, name, meta_specs))
-                }
-                _ => {
-                    Err(CompilationError::InconsistentEntry)
-                }
-            },
-        _ => {
-            Err(CompilationError::InconsistentEntry)
-        }
     }
 }
 
@@ -596,8 +561,7 @@ pub(crate) struct Preprocessor {
 }
 
 impl Preprocessor {
-    pub(super)
+    pub(super) fn new(flags: MachineFlags) -> Self {
-    fn new(flags: MachineFlags) -> Self {
         Preprocessor {
             flags,
             queue: VecDeque::new(),
@@ -606,12 +570,8 @@ impl Preprocessor {
 
     fn setup_fact(&mut self, term: Term) -> Result<Term, CompilationError> {
         match term {
-            Term::Clause(..) | Term::Constant(_, Constant::Atom(..)) => {
+            Term::Clause(..) | Term::Constant(_, Constant::Atom(..)) => Ok(term),
-                Ok(term)
+            _ => Err(CompilationError::InadmissibleFact),
-            }
-            _ => {
-                Err(CompilationError::InadmissibleFact)
-            }
         }
     }
 
@@ -712,109 +672,97 @@ impl Preprocessor {
                     Ok(clause_to_query_term(load_state, name, vec![], fixity))
                 }
             }
-            Term::Constant(_, Constant::Char('!')) => {
+            Term::Constant(_, Constant::Char('!')) => Ok(QueryTerm::BlockedCut),
-                Ok(QueryTerm::BlockedCut)
-            }
             Term::Var(_, ref v) if v.as_str() == "!" => {
                 Ok(QueryTerm::UnblockedCut(Cell::default()))
             }
-            Term::Clause(r, name, mut terms, fixity) => {
+            Term::Clause(r, name, mut terms, fixity) => match (name.as_str(), terms.len()) {
-                match (name.as_str(), terms.len()) {
+                (";", 2) => {
-                    (";", 2) => {
+                    let term = Term::Clause(r, name.clone(), terms, fixity);
-                        let term = Term::Clause(r, name.clone(), terms, fixity);
 
-                        let (stub, clauses) = self.fabricate_disjunct(term);
+                    let (stub, clauses) = self.fabricate_disjunct(term);
-                        self.queue.push_back(clauses);
+                    self.queue.push_back(clauses);
 
-                        Ok(QueryTerm::Jump(stub))
+                    Ok(QueryTerm::Jump(stub))
-                    }
+                }
-                    ("->", 2) => {
+                ("->", 2) => {
-                        let conq = *terms.pop().unwrap();
+                    let conq = *terms.pop().unwrap();
-                        let prec = *terms.pop().unwrap();
+                    let prec = *terms.pop().unwrap();
 
-                        let (stub, clauses) = self.fabricate_if_then(prec, conq);
+                    let (stub, clauses) = self.fabricate_if_then(prec, conq);
-                        self.queue.push_back(clauses);
+                    self.queue.push_back(clauses);
 
-                        Ok(QueryTerm::Jump(stub))
+                    Ok(QueryTerm::Jump(stub))
-                    }
+                }
-                    ("\\+", 1) => {
+                ("\\+", 1) => {
-                        terms.push(Box::new(Term::Constant(
+                    terms.push(Box::new(Term::Constant(
-                            Cell::default(),
+                        Cell::default(),
-                            Constant::Atom(clause_name!("$fail"), None)
+                        Constant::Atom(clause_name!("$fail"), None),
-                        )));
+                    )));
 
-                        let conq = Term::Constant(
+                    let conq =
-                            Cell::default(),
+                        Term::Constant(Cell::default(), Constant::Atom(clause_name!("true"), None));
-                            Constant::Atom(clause_name!("true"), None)
-                        );
 
-                        let prec = Term::Clause(Cell::default(), clause_name!("->"), terms, None);
+                    let prec = Term::Clause(Cell::default(), clause_name!("->"), terms, None);
-                        let terms = vec![Box::new(prec), Box::new(conq)];
+                    let terms = vec![Box::new(prec), Box::new(conq)];
 
-                        let term = Term::Clause(Cell::default(), clause_name!(";"), terms, None);
+                    let term = Term::Clause(Cell::default(), clause_name!(";"), terms, None);
-                        let (stub, clauses) = self.fabricate_disjunct(term);
+                    let (stub, clauses) = self.fabricate_disjunct(term);
 
-                        debug_assert!(clauses.len() > 0);
+                    debug_assert!(clauses.len() > 0);
-                        self.queue.push_back(clauses);
+                    self.queue.push_back(clauses);
 
-                        Ok(QueryTerm::Jump(stub))
+                    Ok(QueryTerm::Jump(stub))
-                    }
+                }
-                    ("$get_level", 1) => {
+                ("$get_level", 1) => {
-                        if let Term::Var(_, ref var) = *terms[0] {
+                    if let Term::Var(_, ref var) = *terms[0] {
-                            Ok(QueryTerm::GetLevelAndUnify(Cell::default(), var.clone()))
+                        Ok(QueryTerm::GetLevelAndUnify(Cell::default(), var.clone()))
-                        } else {
+                    } else {
-                            Err(CompilationError::InadmissibleQueryTerm)
+                        Err(CompilationError::InadmissibleQueryTerm)
-                        }
-                    }
-                    (":", 2) => {
-                        let predicate_name = *terms.pop().unwrap();
-                        let module_name = *terms.pop().unwrap();
-
-                        match (module_name, predicate_name) {
-                            (Term::Constant(_, Constant::Atom(module_name, _)),
-                             Term::Constant(_, Constant::Atom(predicate_name, fixity))) => {
-                                Ok(qualified_clause_to_query_term(
-                                    load_state,
-                                    module_name,
-                                    predicate_name,
-                                    vec![],
-                                    fixity,
-                                ))
-                            }
-                            (Term::Constant(_, Constant::Atom(module_name, _)),
-                             Term::Clause(_, name, terms, fixity)) => {
-                                Ok(qualified_clause_to_query_term(
-                                    load_state,
-                                    module_name,
-                                    name,
-                                    terms,
-                                    fixity,
-                                ))
-                            }
-                            (module_name, predicate_name) => {
-                                terms.push(Box::new(module_name));
-                                terms.push(Box::new(predicate_name));
-
-                                Ok(clause_to_query_term(load_state, name, terms, fixity))
-                            }
-                        }
-                    }
-                    _ => {
-                        Ok(clause_to_query_term(load_state, name, terms, fixity))
                     }
                 }
-            }
+                (":", 2) => {
-            Term::Var(..) => {
+                    let predicate_name = *terms.pop().unwrap();
-                Ok(QueryTerm::Clause(
+                    let module_name = *terms.pop().unwrap();
-                    Cell::default(),
+
-                    ClauseType::CallN,
+                    match (module_name, predicate_name) {
-                    vec![Box::new(term)],
+                        (
-                    false,
+                            Term::Constant(_, Constant::Atom(module_name, _)),
-                ))
+                            Term::Constant(_, Constant::Atom(predicate_name, fixity)),
-            }
+                        ) => Ok(qualified_clause_to_query_term(
-            _ => {
+                            load_state,
-                Err(CompilationError::InadmissibleQueryTerm)
+                            module_name,
-            }
+                            predicate_name,
+                            vec![],
+                            fixity,
+                        )),
+                        (
+                            Term::Constant(_, Constant::Atom(module_name, _)),
+                            Term::Clause(_, name, terms, fixity),
+                        ) => Ok(qualified_clause_to_query_term(
+                            load_state,
+                            module_name,
+                            name,
+                            terms,
+                            fixity,
+                        )),
+                        (module_name, predicate_name) => {
+                            terms.push(Box::new(module_name));
+                            terms.push(Box::new(predicate_name));
+
+                            Ok(clause_to_query_term(load_state, name, terms, fixity))
+                        }
+                    }
+                }
+                _ => Ok(clause_to_query_term(load_state, name, terms, fixity)),
+            },
+            Term::Var(..) => Ok(QueryTerm::Clause(
+                Cell::default(),
+                ClauseType::CallN,
+                vec![Box::new(term)],
+                false,
+            )),
+            _ => Err(CompilationError::InadmissibleQueryTerm),
         }
     }
 
@@ -835,9 +783,7 @@ impl Preprocessor {
                     self.to_query_term(load_state, Term::Clause(r, name, subterms, fixity))
                 }
             }
-            _ => {
+            _ => self.to_query_term(load_state, term),
-                self.to_query_term(load_state, term)
-            }
         }
     }
 
@@ -884,30 +830,23 @@ impl Preprocessor {
         mut terms: Vec<Box<Term>>,
         cut_context: CutContext,
     ) -> Result<Rule, CompilationError> {
-        let post_head_terms: Vec<_> = terms.drain(1 ..).collect();
+        let post_head_terms: Vec<_> = terms.drain(1..).collect();
 
-        let mut query_terms =
+        let mut query_terms = self.setup_query(load_state, post_head_terms, cut_context)?;
-            self.setup_query(load_state, post_head_terms, cut_context)?;
 
-        let clauses = query_terms.drain(1 ..).collect();
+        let clauses = query_terms.drain(1..).collect();
         let qt = query_terms.pop().unwrap();
 
         match *terms.pop().unwrap() {
-            Term::Clause(_, name, terms, _) => {
+            Term::Clause(_, name, terms, _) => Ok(Rule {
-                Ok(Rule {
+                head: (name, terms, qt),
-                    head: (name, terms, qt),
+                clauses,
-                    clauses,
+            }),
-                })
+            Term::Constant(_, Constant::Atom(name, _)) => Ok(Rule {
-            }
+                head: (name, vec![], qt),
-            Term::Constant(_, Constant::Atom(name, _)) => {
+                clauses,
-                Ok(Rule {
+            }),
-                    head: (name, vec![], qt),
+            _ => Err(CompilationError::InvalidRuleHead),
-                    clauses,
-                })
-            }
-            _ => {
-                Err(CompilationError::InvalidRuleHead)
-            }
         }
     }
 
@@ -917,11 +856,14 @@ impl Preprocessor {
         terms: Vec<Box<Term>>,
         cut_context: CutContext,
     ) -> Result<TopLevel, CompilationError> {
-        Ok(TopLevel::Query(self.setup_query(load_state, terms, cut_context)?))
+        Ok(TopLevel::Query(self.setup_query(
+            load_state,
+            terms,
+            cut_context,
+        )?))
     }
 
-    pub(super)
+    pub(super) fn try_term_to_tl<'a>(
-    fn try_term_to_tl<'a>(
         &mut self,
         load_state: &mut LoadState<'a>,
         term: Term,
@@ -944,9 +886,7 @@ impl Preprocessor {
                     Ok(TopLevel::Fact(self.setup_fact(term)?))
                 }
             }
-            term => {
+            term => Ok(TopLevel::Fact(self.setup_fact(term)?)),
-                Ok(TopLevel::Fact(self.setup_fact(term)?))
-            }
         }
     }
 
@@ -965,21 +905,18 @@ impl Preprocessor {
         Ok(results)
     }
 
-    pub(super)
+    pub(super) fn parse_queue<'a>(
-    fn parse_queue<'a>(
         &mut self,
         load_state: &mut LoadState<'a>,
     ) -> Result<VecDeque<TopLevel>, CompilationError> {
         let mut queue = VecDeque::new();
 
         while let Some(terms) = self.queue.pop_front() {
-            let clauses = merge_clauses(
+            let clauses = merge_clauses(&mut self.try_terms_to_tls(
-                &mut self.try_terms_to_tls(
+                load_state,
-                    load_state,
+                terms,
-                    terms,
+                CutContext::HasCutVariable,
-                    CutContext::HasCutVariable,
+            )?)?;
-                )?
-            )?;
 
             queue.push_back(clauses);
         }

src/main.rs

@@ -1,43 +1,35 @@
-extern crate blake2;
+use blake2;
-extern crate chrono;
+use chrono;
-extern crate cpu_time;
+use cpu_time;
-extern crate crossterm;
+use crossterm;
-extern crate divrem;
+use divrem;
-#[macro_use]
+use downcast;
-extern crate downcast;
+use git_version;
-extern crate git_version;
+use indexmap;
-extern crate hostname;
+use lazy_static;
-extern crate indexmap;
+use native_tls;
-#[macro_use]
+use nix::sys::signal;
-extern crate lazy_static;
+use openssl;
-extern crate libc;
+use ordered_float;
-extern crate native_tls;
+use prolog_parser_rebis;
-extern crate nix;
+use ref_thread_local;
-extern crate openssl;
+use ring;
-extern crate ordered_float;
+use ripemd160;
-#[macro_use]
+use rustyline;
-extern crate prolog_parser_rebis;
+use sha3;
-#[macro_use]
+use unicode_reader;
-extern crate ref_thread_local;
-extern crate ring;
-extern crate ripemd160;
-#[cfg(feature = "rug")]
-extern crate rug;
-#[cfg(feature = "num-rug-adapter")]
-extern crate num_rug_adapter as rug;
-extern crate rustyline;
-extern crate sha3;
-extern crate unicode_reader;
 
-use crate::nix::sys::signal;
+#[cfg(feature = "num-rug-adapter")]
+use num_rug_adapter as rug;
+#[cfg(feature = "rug")]
+use rug;
 
 #[macro_use]
 mod macros;
 mod allocator;
 mod arithmetic;
-mod machine;
-mod codegen;
 mod clause_types;
+mod codegen;
 mod debray_allocator;
 mod fixtures;
 mod forms;
@@ -46,17 +38,18 @@ mod heap_print;
 mod indexing;
 mod instructions;
 mod iterators;
+mod machine;
 mod read;
 mod targets;
 mod write;
 
-use machine::*;
 use machine::streams::*;
+use machine::*;
 use read::*;
 
 use std::sync::atomic::Ordering;
 
-extern fn handle_sigint(signal: libc::c_int) {
+extern "C" fn handle_sigint(signal: libc::c_int) {
     let signal = signal::Signal::from_c_int(signal).unwrap();
     if signal == signal::Signal::SIGINT {
         INTERRUPT.store(true, Ordering::Relaxed);