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correct acyclic iteration.

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This commit is contained in:
Mark Thom
2018-02-09 16:31:56 -07:00
parent 5b1475435a
commit 211bdd3a13
1 changed files with 12 additions and 21 deletions
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33
src/prolog/heap_iter.rs
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@@ -146,14 +146,8 @@ pub struct HeapCellAcyclicIterator<HeapCellIter> {
impl<HeapCellIter: MutStackHeapCellIterator> HeapCellAcyclicIterator<HeapCellIter>
{
pub fn new(mut iter: HeapCellIter) -> Self {
let mut seen = HashSet::new();
if let Some(addr) = iter.stack().last() {
seen.insert(addr.clone());
}
HeapCellAcyclicIterator { iter, seen }
pub fn new(iter: HeapCellIter) -> Self {
HeapCellAcyclicIterator { iter, seen: HashSet::new() }
}
}
@@ -162,21 +156,18 @@ impl<HeapCellIter> Iterator for HeapCellAcyclicIterator<HeapCellIter>
+ MutStackHeapCellIterator
{
type Item = HeapCellValue;
fn next(&mut self) -> Option<Self::Item> {
while let Some(hcv) = self.iter.next() {
if let Some(addr) = self.iter.stack().pop() {
if self.seen.contains(&addr) {
continue;
} else {
self.iter.stack().push(addr.clone());
self.seen.insert(addr);
}
}
return Some(hcv);
fn next(&mut self) -> Option<Self::Item> {
while let Some(addr) = self.iter.stack().pop() {
if self.seen.contains(&addr) {
continue;
} else {
self.iter.stack().push(addr.clone());
self.seen.insert(addr);
break;
}
}
None
self.iter.next()
}
}