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add variant_hash and is_non_variant to fix setof/3, bagof/3

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This commit is contained in:
Mark Thom
2025-12-12 18:05:47 -08:00
parent 29cd80510b
commit 6284aa3a3f
12 changed files with 248 additions and 143 deletions
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47
src/machine/system_calls.rs
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@@ -574,53 +574,6 @@ pub(crate) struct FindallCopyInfo {
}
impl MachineState {
// determine whether two terms are variants, i.e. if there exists
// a bijection between their variable sets such that applying it
// to h1 produces h2 (ISO Prolog standard section 7.1.6.1).
// return true on failure and false on success.
#[inline(always)]
pub fn is_not_variant(&self) -> bool {
let h1 = self.registers[1];
let h2 = self.registers[2];
let mut a_to_b = IndexMap::with_hasher(FxBuildHasher::default());
let mut b_to_a = IndexMap::with_hasher(FxBuildHasher::default());
for term_pair in ParallelHeapIter::from(self, h1, h2) {
match term_pair {
TermPair::Vars(v1_offset, v2_offset) => {
match a_to_b.entry(v1_offset) {
indexmap::map::Entry::Occupied(stored_v2_offset) => {
if v2_offset != *stored_v2_offset.get() {
return true;
}
}
indexmap::map::Entry::Vacant(entry) => {
entry.insert_entry(v2_offset);
}
}
match b_to_a.entry(v2_offset) {
indexmap::map::Entry::Occupied(stored_v1_offset) => {
if v1_offset != *stored_v1_offset.get() {
return true;
}
}
indexmap::map::Entry::Vacant(entry) => {
entry.insert_entry(v1_offset);
}
}
}
TermPair::Less(..) => return true,
TermPair::Greater(..) => return true,
TermPair::Unordered(cell_1, cell_2) if cell_1 != cell_2 => return true,
_ => {}
}
}
false
}
fn copy_lifted_heap_from_offset(&mut self, offset: usize, lh_offset: usize) {
let reserve_size = self.lifted_heap.cell_len() - lh_offset;
let mut writer = step_or_resource_error!(self, self.heap.reserve(reserve_size));