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evacuate arguments on overwrite.

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This commit is contained in:
Mark Thom
2017-05-25 16:41:36 -06:00
parent cf470e48c2
commit 4d6897509d
9 changed files with 80 additions and 54 deletions
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24
src/prolog/debray_allocator.rs
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@@ -14,7 +14,14 @@ pub struct DebrayAllocator<'a> {
in_use: BTreeSet<usize>,
}
impl<'a> DebrayAllocator<'a> {
impl<'a> DebrayAllocator<'a> {
fn is_curr_arg_distinct_from(&self, var: &'a Var) -> bool {
match self.contents.get(&self.arg_c) {
Some(t_var) if **t_var != *var => true,
_ => false
}
}
fn occurs_shallowly_in_head(&self, var: &'a Var, r: usize) -> bool
{
match self.bindings.get(var).unwrap() {
@@ -142,6 +149,7 @@ impl<'a> DebrayAllocator<'a> {
match term_loc {
GenContext::Head =>
if let Level::Shallow = lvl {
self.evacuate_arg(0, target);
self.alloc_with_cr(var)
} else {
self.alloc_with_ca(var)
@@ -262,14 +270,22 @@ impl<'a> Allocator<'a> for DebrayAllocator<'a>
RegType::Perm(0) => {
let pr = cell.get().norm();
self.record_register(var, pr);
(pr, true)
},
r => (r, false)
r => (r, false)
};
match lvl {
Level::Shallow => {
let k = self.arg_c;
if !r.is_perm() {
if self.is_curr_arg_distinct_from(var) {
self.evacuate_arg(term_loc.chunk_num(), target);
}
}
self.arg_c += 1;
cell.set(VarReg::ArgAndNorm(r, k));
@@ -295,14 +311,14 @@ impl<'a> Allocator<'a> for DebrayAllocator<'a>
Level::Deep =>
target.push(Target::subterm_to_value(r))
};
if !r.is_perm() {
let o = r.reg_num();
self.contents.insert(o, var);
self.record_register(var, r);
self.in_use.insert(o);
}
}
}
fn reset(&mut self) {