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bug fixes on LCO, backtracking.

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This commit is contained in:
Mark Thom
2017-12-10 01:24:23 -07:00
parent e44ad111c5
commit 37f4450c34
9 changed files with 107 additions and 106 deletions
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2
src/main.rs
View File

@@ -34,7 +34,7 @@ mod tests {
submit(&mut wam, "p(Z, Z).");
submit(&mut wam, "clouds(are, nice).");
// submit returns true on failure, false on success.
// submit returns false on failure, true on success.
assert_eq!(submit(&mut wam, "?- p(Z, Z)."), true);
assert_eq!(submit(&mut wam, "?- p(Z, z)."), true);
assert_eq!(submit(&mut wam, "?- p(Z, w)."), true);

12
src/prolog/ast.rs
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@@ -317,7 +317,7 @@ pub enum Term {
pub enum InlinedQueryTerm {
CompareNumber(CompareNumberQT, Vec<Box<Term>>),
IsAtomic(Vec<Box<Term>>),
IsVar(Vec<Box<Term>>)
IsVar(Vec<Box<Term>>),
}
impl InlinedQueryTerm {
@@ -325,7 +325,7 @@ impl InlinedQueryTerm {
match self {
&InlinedQueryTerm::CompareNumber(_, _) => 2,
&InlinedQueryTerm::IsAtomic(_) => 1,
&InlinedQueryTerm::IsVar(_) => 1
&InlinedQueryTerm::IsVar(_) => 1,
}
}
}
@@ -344,8 +344,8 @@ pub enum QueryTerm {
CallN(Vec<Box<Term>>),
Catch(Vec<Box<Term>>),
Cut,
Is(Vec<Box<Term>>),
Inlined(InlinedQueryTerm),
Is(Vec<Box<Term>>),
Term(Term),
Throw(Vec<Box<Term>>)
}
@@ -756,8 +756,6 @@ impl ControlInstruction {
&ControlInstruction::ThrowExecute => true,
&ControlInstruction::Goto(_, _) => true,
&ControlInstruction::Proceed => true,
&ControlInstruction::IsCall(_, _) => true,
&ControlInstruction::IsExecute(_, _) => true,
_ => false
}
}
@@ -963,10 +961,6 @@ pub struct Heap {
}
impl Heap {
pub fn new() -> Self {
Heap { heap: vec![], h : 0 }
}
pub fn with_capacity(cap: usize) -> Self {
Heap { heap: vec![HeapCellValue::Str(0); cap], h: 0 }
}

17
src/prolog/codegen.rs
View File

@@ -280,12 +280,12 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<'a, TermMarker>
*ctrl = ControlInstruction::Execute(name, arity),
ControlInstruction::CallN(arity) =>
*ctrl = ControlInstruction::ExecuteN(arity),
ControlInstruction::IsCall(r, at) =>
*ctrl = ControlInstruction::IsExecute(r, at),
ControlInstruction::CatchCall =>
*ctrl = ControlInstruction::CatchExecute,
ControlInstruction::ThrowCall =>
*ctrl = ControlInstruction::ThrowExecute,
ControlInstruction::IsCall(r, at) =>
*ctrl = ControlInstruction::IsExecute(r, at),
ControlInstruction::Proceed => {},
_ => dealloc_index += 1 // = code.len()
}
@@ -376,10 +376,8 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<'a, TermMarker>
Line::Cut(CutInstruction::Cut(is_terminal))
});
},
&QueryTerm::Inlined(ref term) =>
self.compile_inlined(term, term_loc, code)?,
&QueryTerm::Is(ref terms) => {
let (mut acode, at) = try!(self.call_arith_eval(terms[1].as_ref(), 1));
let (mut acode, at) = self.call_arith_eval(terms[1].as_ref(), 1)?;
code.append(&mut acode);
match terms[0].as_ref() {
@@ -405,11 +403,20 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<'a, TermMarker>
temp_v!(1))]);
code.push(is_call!(temp_v!(1), at.unwrap_or(interm!(1))));
},
&Term::Constant(_, Constant::Rational(ref r)) => {
let r = r.clone();
code.push(query![put_constant!(Level::Shallow,
Constant::Rational(r),
temp_v!(1))]);
code.push(is_call!(temp_v!(1), at.unwrap_or(interm!(1))));
},
_ => {
code.push(fail!());
}
}
},
&QueryTerm::Inlined(ref term) =>
self.compile_inlined(term, term_loc, code)?,
_ if chunk_num == 0 => {
self.marker.reset_arg(term.arity());

2
src/prolog/fixtures.rs
View File

@@ -279,7 +279,7 @@ impl<'a> VariableFixtures<'a>
{
for term_ref in head.breadth_first_iter() {
match term_ref {
TermRef::Var(_, cell, _) => {
TermRef::Var(Level::Shallow, cell, _) => {
unsafe_vars.remove(&cell.get().norm());
},
_ => {}

8
src/prolog/io.rs
View File

@@ -114,16 +114,16 @@ impl fmt::Display for ControlInstruction {
write!(f, "execute {}/{}", name, arity),
&ControlInstruction::Goto(p, arity) =>
write!(f, "goto {}/{}", p, arity),
&ControlInstruction::IsCall(r, ref at) =>
write!(f, "is_call {}, {}", r, at),
&ControlInstruction::IsExecute(r, ref at) =>
write!(f, "is_execute {}, {}", r, at),
&ControlInstruction::Proceed =>
write!(f, "proceed"),
&ControlInstruction::ThrowCall =>
write!(f, "call_throw"),
&ControlInstruction::ThrowExecute =>
write!(f, "execute_throw"),
&ControlInstruction::IsCall(r, ref at) =>
write!(f, "is_call {}, {}", r, at),
&ControlInstruction::IsExecute(r, ref at) =>
write!(f, "is_execute {}, {}", r, at),
}
}
}

76
src/prolog/machine.rs
View File

@@ -11,6 +11,7 @@ use prolog::or_stack::*;
use prolog::ordered_float::OrderedFloat;
use prolog::fixtures::*;
use std::cmp::max;
use std::collections::HashMap;
use std::ops::{Index, IndexMut};
use std::vec::Vec;
@@ -325,6 +326,7 @@ impl Machine {
self.ms.execute_fact_instr(&fact_instr);
}
self.ms.p += 1;
},
&Line::Indexing(ref indexing_instr) =>
@@ -339,6 +341,7 @@ impl Machine {
self.ms.execute_query_instr(&query_instr);
}
self.ms.p += 1;
}
}
@@ -398,6 +401,7 @@ impl Machine {
match var_data {
&VarData::Perm(_) => {
let e = self.ms.e;
let r = var_data.as_reg_type().reg_num();
let addr = self.ms.and_stack[e][r].clone();
@@ -641,8 +645,9 @@ impl MachineState {
}
}
fn num_frames(&self) -> usize {
self.and_stack.len() + self.or_stack.len()
fn next_global_index(&self) -> usize {
max(if self.and_stack.len() > 0 { self.and_stack[self.e].global_index } else { 0 },
if self.b > 0 { self.or_stack[self.b - 1].global_index } else { 0 }) + 1
}
fn store(&self, a: Addr) -> Addr {
@@ -860,7 +865,7 @@ impl MachineState {
match at {
&ArithmeticTerm::Reg(r) => {
let addr = self[r].clone();
let item = self.deref(addr);
let item = self.store(self.deref(addr));
match item {
Addr::Con(Constant::Integer(bi)) =>
@@ -1663,6 +1668,7 @@ impl MachineState {
if nb > 0 && self.or_stack[b].b == nb {
self.b = self.or_stack[nb - 1].b;
self.or_stack.truncate(self.b);
}
self.p += 1;
@@ -1691,6 +1697,8 @@ impl MachineState {
},
&BuiltInInstruction::UnwindStack => {
self.b = self.block;
self.or_stack.truncate(self.b);
self.fail = true;
},
&BuiltInInstruction::IsAtomic(r) => {
@@ -1732,35 +1740,33 @@ impl MachineState {
{
match instr {
&ControlInstruction::Allocate(num_cells) => {
if let Some(ref or_fr) = self.or_stack.top() {
let and_gi = if self.and_stack.len() > self.e {
self.and_stack[self.e].global_index
} else {
0
};
let gi = self.next_global_index();
if and_gi <= or_fr.global_index {
self.e = or_fr.e;
}
}
self.p += 1;
if self.e + 1 < self.and_stack.len() {
let and_gi = self.and_stack[self.e].global_index;
let or_gi = self.or_stack.top()
.map(|or_fr| or_fr.global_index)
.unwrap_or(0);
if and_gi > or_gi {
let index = self.e + 1;
self.and_stack[index].e = self.e;
self.and_stack[index].cp = self.cp;
self.and_stack[index].global_index = gi;
self.and_stack.resize(index, num_cells);
self.e = index;
} else {
let num_frames = self.num_frames();
self.and_stack.push(num_frames + 1, self.e, self.cp, num_cells);
return;
}
}
self.and_stack.push(gi, self.e, self.cp, num_cells);
self.e = self.and_stack.len() - 1;
};
self.p += 1;
},
&ControlInstruction::Call(ref name, arity, _) =>
self.try_call_predicate(code_dir, name.clone(), arity),
@@ -1798,15 +1804,6 @@ impl MachineState {
self.b0 = self.b;
self.p = CodePtr::DirEntry(p);
},
&ControlInstruction::Proceed =>
self.p = self.cp,
&ControlInstruction::ThrowCall => {
self.cp = self.p + 1;
self.goto_throw();
},
&ControlInstruction::ThrowExecute => {
self.goto_throw();
},
&ControlInstruction::IsCall(r, ref at) => {
let a1 = self[r].clone();
let a2 = try_or_fail!(self, self.get_number(at));
@@ -1820,7 +1817,16 @@ impl MachineState {
self.unify(a1, Addr::Con(Constant::from(a2)));
self.p = self.cp;
}
},
&ControlInstruction::Proceed =>
self.p = self.cp,
&ControlInstruction::ThrowCall => {
self.cp = self.p + 1;
self.goto_throw();
},
&ControlInstruction::ThrowExecute => {
self.goto_throw();
},
};
}
@@ -1829,9 +1835,9 @@ impl MachineState {
match instr {
&IndexedChoiceInstruction::Try(l) => {
let n = self.num_of_args;
let num_frames = self.num_frames();
let gi = self.next_global_index();
self.or_stack.push(num_frames + 1,
self.or_stack.push(gi,
self.e,
self.cp,
self.b,
@@ -1899,7 +1905,7 @@ impl MachineState {
self.heap.truncate(self.or_stack[b].h);
self.b = self.or_stack[b].b;
self.or_stack.pop();
self.or_stack.truncate(self.b);
self.hb = self.heap.h;
self.p += l;
@@ -1912,9 +1918,9 @@ impl MachineState {
match instr {
&ChoiceInstruction::TryMeElse(offset) => {
let n = self.num_of_args;
let num_frames = self.num_frames();
let gi = self.next_global_index();
self.or_stack.push(num_frames + 1,
self.or_stack.push(gi,
self.e,
self.cp,
self.b,
@@ -1983,7 +1989,7 @@ impl MachineState {
self.b = self.or_stack[b].b;
self.or_stack.pop();
self.or_stack.truncate(self.b);
self.hb = self.heap.h;
self.p += 1;

8
src/prolog/macros.rs
View File

@@ -135,14 +135,6 @@ macro_rules! is_var {
)
}
/*
macro_rules! retry_me_else {
($o:expr) => (
Line::Choice(ChoiceInstruction::RetryMeElse($o))
)
}
*/
macro_rules! trust_me {
() => (
Line::Choice(ChoiceInstruction::TrustMe)

6
src/prolog/or_stack.rs
View File

@@ -78,8 +78,10 @@ impl OrStack {
self.0.last()
}
pub fn pop(&mut self) {
self.0.pop();
// truncate expects a 1-indexed new_b, ie.
// the value b of MachineState.
pub fn truncate(&mut self, new_b: usize) {
self.0.truncate(new_b);
}
pub fn is_empty(&self) -> bool {