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add term variables

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This commit is contained in:
Mark Thom
2018-09-24 23:33:47 -06:00
parent 5e30fa6264
commit 4cf1aa0d8f
6 changed files with 70 additions and 33 deletions
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4
README.md
View File

@@ -33,7 +33,7 @@ Extend rusty-wam to include the following, among other features:
* Default representation of strings as list of chars, using a packed
internal representation (_done_).
- A representation of 'partial strings' as difference lists
of characters (_in progress_).
of characters (_done_).
* `term_expansion/2` and `goal_expansion/2` (_in progress_).
* Definite Clause Grammars.
* Attributed variables using the SICStus Prolog interface and
@@ -153,6 +153,7 @@ The following predicates are built-in to rusty-wam.
* `member/2`
* `memberchk/2`
* `nonvar/1`
* `numbervars/{2,3}`
* `once/1`
* `partial_string/2`
* `rational/1`
@@ -163,6 +164,7 @@ The following predicates are built-in to rusty-wam.
* `setup_call_cleanup/3`
* `sort/2`
* `string/1`
* `term_variables/2`
* `throw/1`
* `true/0`
* `var/1`

3
src/prolog/instructions.rs
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@@ -238,6 +238,7 @@ pub enum SystemClauseType {
SetDoubleQuotes,
SkipMaxList,
Succeed,
TermVariables,
UnwindStack
}
@@ -275,6 +276,7 @@ impl SystemClauseType {
&SystemClauseType::SetDoubleQuotes => clause_name!("$set_double_quotes"),
&SystemClauseType::SkipMaxList => clause_name!("$skip_max_list"),
&SystemClauseType::Succeed => clause_name!("$succeed"),
&SystemClauseType::TermVariables => clause_name!("$term_variables"),
&SystemClauseType::UnwindStack => clause_name!("$unwind_stack"),
}
}
@@ -308,6 +310,7 @@ impl SystemClauseType {
("$set_cp_by_default", 1) => Some(SystemClauseType::SetCutPointByDefault(temp_v!(1))),
("$set_double_quotes", 1) => Some(SystemClauseType::SetDoubleQuotes),
("$skip_max_list", 4) => Some(SystemClauseType::SkipMaxList),
("$term_variables", 2) => Some(SystemClauseType::TermVariables),
("$unwind_stack", 0) => Some(SystemClauseType::UnwindStack),
_ => None
}

29
src/prolog/lib/numbervars.pl
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@@ -1,29 +0,0 @@
:- module(numbervars, [numbervars/2, numbervars/3]).
numbervars(Term, NewTerm) :- duplicate_term(Term, NewTerm), numbervars(Term, NewTerm, 0, _).
numbervars(Term, NewTerm, N) :-
( integer(N), N >= 0 -> duplicate_term(Term, NewTerm), numbervars(Term, NewTerm, N, _)
; integer(N) -> throw(error(domain_error(not_less_than_zero, N), numbervars/3))
; throw(error(type_error(integer, N), numbervars/3))
).
numbervars(Term, NewTerm, N1, N2) :-
var(Term), !, NewTerm = '$VAR'(N1), N2 is N1 + 1.
numbervars(Term, NewTerm, N1, N2) :- compound(Term), !,
Term =.. [Name | Args],
NewTerm =.. [Name | NewArgs],
fold_numbervars(Args, NewArgs, N1, N2).
numbervars(_, _, N, N).
marked_already(Term, NewTerm) :-
var(Term), nonvar(NewTerm), NewTerm = '$VAR'(_).
marked_already(Term, NewTerm) :-
atomic(Term).
fold_numbervars([HeadTerm | Terms], [NewHeadTerm | NewTerms], N1, Nn) :-
( marked_already(HeadTerm, NewHeadTerm) -> N1 = N2
; numbervars(HeadTerm, NewHeadTerm, N1, N2)
),
fold_numbervars(Terms, NewTerms, N2, Nn).
fold_numbervars([], [], N, N).

19
src/prolog/lib/terms.pl Normal file
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@@ -0,0 +1,19 @@
:- module(terms, [term_variables/2, numbervars/2, numbervars/3]).
term_variables(Term, Vars) :- '$term_variables'(Term, Vars).
numbervars(Term, N) :-
integer(N),
term_variables(Term, Vars),
numberlist(Vars, N, N1).
numbervars(Term, N0, N) :-
integer(N0),
integer(N),
term_variables(Term, Vars),
numberlist(Vars, N0, N).
numberlist([], N,N).
numberlist(['$VAR'(N0)|Vars], N0,N) :-
N1 is N0+1,
numberlist(Vars, N1,N).

4
src/prolog/machine/mod.rs
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@@ -120,7 +120,7 @@ impl<'a> SubModuleUser for MachineCodeIndices<'a> {
static LISTS: &str = include_str!("../lib/lists.pl");
static CONTROL: &str = include_str!("../lib/control.pl");
static QUEUES: &str = include_str!("../lib/queues.pl");
static NUMVARS: &str = include_str!("../lib/numbervars.pl");
static TERMS: &str = include_str!("../lib/terms.pl");
impl Machine {
pub fn new() -> Self {
@@ -144,7 +144,7 @@ impl Machine {
compile_user_module(&mut wam, LISTS.as_bytes());
compile_user_module(&mut wam, CONTROL.as_bytes());
compile_user_module(&mut wam, QUEUES.as_bytes());
compile_user_module(&mut wam, NUMVARS.as_bytes());
compile_user_module(&mut wam, TERMS.as_bytes());
wam
}

44
src/prolog/machine/system_calls.rs
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@@ -1,13 +1,14 @@
use prolog_parser::ast::*;
use prolog::heap_iter::*;
use prolog::instructions::*;
use prolog::machine::MachineCodeIndices;
use prolog::machine::machine_errors::*;
use prolog::machine::machine_state::*;
use prolog::num::{ToPrimitive, Zero};
use prolog::num::bigint::{BigInt};
//use prolog::term_writer::*;
use std::collections::HashSet;
use std::rc::Rc;
struct BrentAlgState {
@@ -435,6 +436,47 @@ impl MachineState {
return Err(err);
},
&SystemClauseType::Succeed => {},
&SystemClauseType::TermVariables => {
let a1 = self[temp_v!(1)].clone();
let mut vars = Vec::new();
{
let iter = HCPreOrderIterator::new(self, a1);
for item in iter {
match item {
HeapCellValue::Addr(Addr::HeapCell(h)) =>
vars.push(Ref::HeapCell(h)),
HeapCellValue::Addr(Addr::StackCell(fr, sc)) =>
vars.push(Ref::StackCell(fr, sc)),
_ => {}
}
}
}
let mut h = self.heap.h;
let outcome = Addr::HeapCell(h);
let mut seen_vars = HashSet::new();
for r in vars {
if seen_vars.contains(&r) {
continue;
}
self.heap.push(HeapCellValue::Addr(Addr::Lis(h+1)));
self.heap.push(HeapCellValue::Addr(r.as_addr()));
h += 2;
seen_vars.insert(r);
}
self.heap.push(HeapCellValue::Addr(Addr::Con(Constant::EmptyList)));
let a2 = self[temp_v!(2)].clone();
self.unify(a2, outcome);
},
&SystemClauseType::UnwindStack => self.unwind_stack()
};