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add cyclic_term

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This commit is contained in:
Mark Thom
2018-03-28 23:41:19 -06:00
parent ef65c996ec
commit 7b160199fd
9 changed files with 72 additions and 41 deletions
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1
README.md
View File

@@ -134,6 +134,7 @@ The following predicates are built-in to rusty-wam.
* `catch/3`
* `compare/3`
* `compound/1`
* `cyclic_term/1`
* `display/1`
* `duplicate_term/2`
* `false/0`

27
src/prolog/ast.rs
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@@ -132,11 +132,14 @@ impl PredicateClause {
}
pub type OpDirKey = (ClauseName, Fixity);
// name and fixity -> operator type and precedence.
pub type OpDir = HashMap<OpDirKey, (Specifier, usize, ClauseName)>;
pub type CodeDir = HashMap<PredicateKey, (usize, ClauseName)>;
pub type TermDir = HashMap<PredicateKey, Predicate>;
pub type PredicateKey = (ClauseName, usize); // name, arity.
pub struct ModuleDecl {
@@ -249,11 +252,7 @@ impl TopLevel {
&TopLevel::Declaration(_) => None,
&TopLevel::Fact(ref term) => term.name(),
&TopLevel::Predicate(ref clauses) =>
if let Some(ref term) = clauses.first() {
term.name()
} else {
None
},
clauses.first().and_then(|ref term| term.name()),
&TopLevel::Query(_) => None,
&TopLevel::Rule(Rule { ref head, .. }) =>
Some(head.0.clone())
@@ -270,6 +269,15 @@ impl TopLevel {
&TopLevel::Rule(Rule { ref head, .. }) => head.1.len()
}
}
pub fn as_predicate(self) -> Option<Predicate> {
match self {
TopLevel::Fact(term) => Some(vec![PredicateClause::Fact(term)]),
TopLevel::Rule(rule) => Some(vec![PredicateClause::Rule(rule)]),
TopLevel::Predicate(pred) => Some(pred),
_ => None
}
}
}
#[derive(Clone, Copy)]
@@ -680,6 +688,7 @@ pub enum ClauseType {
Catch,
Compare,
CompareTerm(CompareTermQT),
CyclicTerm,
Display,
DuplicateTerm,
Eq,
@@ -775,12 +784,13 @@ impl ClauseType {
pub fn name(&self) -> ClauseName {
match self {
&ClauseType::AcyclicTerm => clause_name!("acyclic_term"),
&ClauseType::Arg => clause_name!("arg"),
&ClauseType::Arg => clause_name!("arg"),
&ClauseType::CallN => clause_name!("call"),
&ClauseType::CallWithInferenceLimit => clause_name!("call_with_inference_limit"),
&ClauseType::Catch => clause_name!("catch"),
&ClauseType::Compare => clause_name!("compare"),
&ClauseType::CompareTerm(qt) => clause_name!(qt.name()),
&ClauseType::CyclicTerm => clause_name!("cyclic_term"),
&ClauseType::Display => clause_name!("display"),
&ClauseType::DuplicateTerm => clause_name!("duplicate_term"),
&ClauseType::Eq => clause_name!("=="),
@@ -806,6 +816,7 @@ impl ClauseType {
("call_with_inference_limit", 3) => ClauseType::CallWithInferenceLimit,
("catch", 3) => ClauseType::Catch,
("compare", 3) => ClauseType::Compare,
("cyclic_term", 1) => ClauseType::CyclicTerm,
("@>", 2) => ClauseType::CompareTerm(CompareTermQT::GreaterThan),
("@<", 2) => ClauseType::CompareTerm(CompareTermQT::LessThan),
("@>=", 2) => ClauseType::CompareTerm(CompareTermQT::GreaterThanOrEqual),
@@ -1200,7 +1211,7 @@ pub enum BuiltInInstruction {
CompareNumber(CompareNumberQT, ArithmeticTerm, ArithmeticTerm),
DefaultRetryMeElse(usize),
DefaultSetCutPoint(RegType),
DefaultTrustMe,
DefaultTrustMe,
EraseBall,
Fail,
GetArg(bool), // last call.
@@ -1211,7 +1222,7 @@ pub enum BuiltInInstruction {
InstallCleaner,
InstallInferenceCounter(RegType, RegType, RegType),
InstallNewBlock,
InternalCallN,
InternalCallN,
RemoveCallPolicyCheck,
RemoveInferenceCounter(RegType, RegType),
ResetBlock,

5
src/prolog/builtins.rs
View File

@@ -626,6 +626,7 @@ fn get_builtins() -> Code {
sort_execute!(), // sort/2, 467.
keysort_execute!(), // keysort/2, 468.
acyclic_term_execute!(), // acyclic_term/1, 469.
cyclic_term_execute!(), // cyclic_term/1, 470.
]
}
@@ -742,6 +743,7 @@ pub fn build_code_and_op_dirs() -> (CodeDir, OpDir)
code_dir.insert((clause_name!("sort"), 2), (467, builtin.clone()));
code_dir.insert((clause_name!("keysort"), 2), (468, builtin.clone()));
code_dir.insert((clause_name!("acyclic_term"), 1), (469, builtin.clone()));
code_dir.insert((clause_name!("cyclic_term"), 1), (470, builtin.clone()));
(code_dir, op_dir)
}
@@ -804,7 +806,8 @@ pub fn builtin_module() -> Module
(clause_name!("atom"), 1),
(clause_name!("sort"), 2),
(clause_name!("keysort"), 2),
(clause_name!("acyclic_term"), 1)]);
(clause_name!("acyclic_term"), 1),
(clause_name!("cyclic_term"), 1)]);
for arity in 0 .. 63 {
module_decl.exports.push((clause_name!("call"), arity));

2
src/prolog/codegen.rs
View File

@@ -7,7 +7,7 @@ use prolog::iterators::*;
use prolog::targets::*;
use std::cell::Cell;
use std::collections::HashMap;
use std::collections::{HashMap};
use std::rc::Rc;
use std::vec::Vec;

2
src/prolog/io.rs
View File

@@ -496,7 +496,7 @@ fn compile_decl(wam: &mut Machine, tl: TopLevel, queue: Vec<TopLevel>) -> EvalSe
if !code.is_empty() {
if let Some(name) = tl.name() {
wam.add_user_code(name, tl.arity(), code)
wam.add_user_code(name, tl.arity(), code, tl.as_predicate().unwrap())
} else {
EvalSession::from(EvalError::NamelessEntry)
}

34
src/prolog/machine/machine_state.rs
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@@ -1,7 +1,6 @@
use prolog::and_stack::*;
use prolog::ast::*;
use prolog::copier::*;
use prolog::heap_iter::*;
use prolog::num::{BigInt, BigUint, Zero, One};
use prolog::or_stack::*;
use prolog::heap_print::*;
@@ -10,7 +9,7 @@ use prolog::tabled_rc::*;
use downcast::Any;
use std::cmp::Ordering;
use std::collections::{HashMap, HashSet};
use std::collections::HashMap;
use std::mem::swap;
use std::ops::{Index, IndexMut};
use std::rc::Rc;
@@ -397,30 +396,8 @@ pub(crate) trait CallPolicy: Any {
{
match ct {
&ClauseType::AcyclicTerm => {
let addr = machine_st[temp_v!(1)].clone();
let mut seen = HashSet::new();
let mut fail = false;
{
let mut iter = machine_st.pre_order_iter(addr);
loop {
if let Some(addr) = iter.stack().last() {
if !seen.contains(addr) {
seen.insert(addr.clone());
} else {
fail = true;
break;
}
}
if iter.next().is_none() {
break;
}
}
}
machine_st.fail = fail;
let addr = machine_st[temp_v!(1)].clone();
machine_st.fail = machine_st.is_cyclic_term(addr);
return_from_clause!(lco, machine_st)
},
&ClauseType::Arg => {
@@ -476,6 +453,11 @@ pub(crate) trait CallPolicy: Any {
return_from_clause!(lco, machine_st)
},
&ClauseType::CyclicTerm => {
let addr = machine_st[temp_v!(1)].clone();
machine_st.fail = !machine_st.is_cyclic_term(addr);
return_from_clause!(lco, machine_st)
},
&ClauseType::Display => {
let output = machine_st.print_term(machine_st[temp_v!(1)].clone(),
DisplayFormatter {},

26
src/prolog/machine/machine_state_impl.rs
View File

@@ -11,7 +11,7 @@ use prolog::or_stack::*;
use prolog::tabled_rc::*;
use std::cmp::{max, Ordering};
use std::collections::HashMap;
use std::collections::{HashMap, HashSet};
use std::rc::Rc;
macro_rules! try_or_fail {
@@ -1001,6 +1001,30 @@ impl MachineState {
}
}
pub(super) fn is_cyclic_term(&self, addr: Addr) -> bool {
let mut seen = HashSet::new();
let mut fail = false;
let mut iter = self.pre_order_iter(addr);
loop {
if let Some(addr) = iter.stack().last() {
if !seen.contains(addr) {
seen.insert(addr.clone());
} else {
fail = true;
break;
}
}
if iter.next().is_none() {
break;
}
}
fail
}
fn try_get_arg(&mut self) -> Result<(), Vec<HeapCellValue>>
{
let a1 = self.store(self.deref(self[temp_v!(1)].clone()));

10
src/prolog/machine/mod.rs
View File

@@ -25,8 +25,9 @@ pub struct Machine {
call_policy: Box<CallPolicy>,
cut_policy: Box<CutPolicy>,
code: Code,
code_dir: CodeDir,
code_dir: CodeDir,
pub op_dir: OpDir,
term_dir: TermDir,
modules: HashMap<ClauseName, Module>,
cached_query: Option<Code>
}
@@ -68,6 +69,7 @@ impl Machine {
cut_policy: Box::new(DefaultCutPolicy {}),
code,
code_dir,
term_dir: TermDir::new(),
op_dir,
modules: HashMap::new(),
cached_query: None
@@ -173,7 +175,8 @@ impl Machine {
self.code.extend(code.into_iter());
}
pub fn add_user_code(&mut self, name: ClauseName, arity: usize, code: Code) -> EvalSession
pub fn add_user_code(&mut self, name: ClauseName, arity: usize, code: Code, pred: Predicate)
-> EvalSession
{
match self.code_dir.get(&(name.clone(), arity)) {
Some(&(_, ref mod_name)) if mod_name == &clause_name!("builtin") =>
@@ -184,8 +187,9 @@ impl Machine {
let offset = self.code.len();
self.code.extend(code.into_iter());
self.term_dir.insert((name.clone(), arity), pred);
self.code_dir.insert((name, arity), (offset, clause_name!("user")));
EvalSession::EntrySuccess
}

6
src/prolog/macros.rs
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@@ -734,6 +734,12 @@ macro_rules! acyclic_term_execute {
)
}
macro_rules! cyclic_term_execute {
() => (
Line::Control(ControlInstruction::CallClause(ClauseType::CyclicTerm, 1, 0, true))
)
}
macro_rules! return_from_clause {
($lco:expr, $machine_st:expr) => {{
if $lco {