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use copy_term/3 to print residual goals (#254)

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This commit is contained in:
Mark Thom
2020-04-04 18:44:16 -06:00
parent 141f3bcec3
commit bbf1aa1668
1 changed files with 31 additions and 15 deletions
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46
src/prolog/machine/copier.rs
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@@ -53,13 +53,27 @@ impl<T: CopierTarget> CopyTermState<T> {
&mut self.target[scan] &mut self.target[scan]
} }
fn copy_list(&mut self, addr: usize) { fn trail_list_cell(&mut self, addr: usize, threshold: usize) {
if let Addr::Lis(h) = self.target[addr + 1].as_addr(addr + 1) { let trail_item = mem::replace(
if h >= self.old_h { &mut self.target[addr],
*self.value_at_scan() = HeapCellValue::Addr(Addr::Lis(h)); HeapCellValue::Addr(Addr::Lis(threshold)),
self.scan += 1; );
return; self.trail.push((
Ref::HeapCell(addr),
trail_item,
));
}
fn copy_list(&mut self, addr: usize) {
for offset in 0 .. 2 {
if let Addr::Lis(h) = self.target[addr + offset].as_addr(addr + offset) {
if h >= self.old_h {
*self.value_at_scan() = HeapCellValue::Addr(Addr::Lis(h));
self.scan += 1;
return;
}
} }
} }
@@ -74,15 +88,14 @@ impl<T: CopierTarget> CopyTermState<T> {
let cdr = self.target.store(self.target.deref(Addr::HeapCell(addr + 1))); let cdr = self.target.store(self.target.deref(Addr::HeapCell(addr + 1)));
if let Addr::Lis(_) = cdr { if !cdr.is_ref() {
let tail_addr = self.target[addr + 1].as_addr(addr + 1); self.trail_list_cell(addr + 1, threshold);
} else {
let car = self.target.store(self.target.deref(Addr::HeapCell(addr)));
self.trail.push(( if !car.is_ref() {
Ref::HeapCell(addr + 1), self.trail_list_cell(addr, threshold);
HeapCellValue::Addr(tail_addr), }
));
self.target[addr + 1] = HeapCellValue::Addr(Addr::Lis(threshold));
} }
self.scan += 1; self.scan += 1;
@@ -163,7 +176,7 @@ impl<T: CopierTarget> CopyTermState<T> {
}; };
self.target[frontier] = HeapCellValue::Addr(Addr::HeapCell(threshold)); self.target[frontier] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.target[h] = HeapCellValue::Addr(Addr::HeapCell(frontier)); self.target[h] = HeapCellValue::Addr(Addr::HeapCell(threshold));
self.trail.push(( self.trail.push((
Ref::AttrVar(h), Ref::AttrVar(h),
@@ -271,6 +284,9 @@ impl<T: CopierTarget> CopyTermState<T> {
*self.value_at_scan() = HeapCellValue::Addr(addr); *self.value_at_scan() = HeapCellValue::Addr(addr);
} }
} }
Addr::Lis(h) if h >= self.old_h => {
self.scan += 1;
}
Addr::Lis(h) => { Addr::Lis(h) => {
self.copy_list(h); self.copy_list(h);
} }