rishi/scryer-prolog
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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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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 {},