rishi/scryer-prolog
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add randomness predicates, small but consequential changes to TrailRef

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This commit is contained in:
Mark Thom
2019-10-17 00:21:21 -06:00
parent a641822a1b
commit ab9a14cc6a
6 changed files with 99 additions and 17 deletions
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28
src/prolog/machine/machine_state_impl.rs
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@@ -648,9 +648,15 @@ impl MachineState {
self.tr += 1;
}
}
TrailRef::AttrVarLink(h, prev_addr) => {
TrailRef::AttrVarHeapLink(h) => {
if h < self.hb {
self.trail.push(TrailRef::AttrVarLink(h, prev_addr));
self.trail.push(TrailRef::AttrVarHeapLink(h));
self.tr += 1;
}
}
TrailRef::AttrVarListLink(h, l) => {
if h < self.hb {
self.trail.push(TrailRef::AttrVarListLink(h, l));
self.tr += 1;
}
}
@@ -680,7 +686,7 @@ impl MachineState {
// additions, now that deleted attributes can be undeleted by
// backtracking.
for i in (a1..a2).rev() {
match self.trail[i].clone() {
match self.trail[i] {
TrailRef::Ref(Ref::HeapCell(h)) => {
self.heap[h] = HeapCellValue::Addr(Addr::HeapCell(h))
}
@@ -690,8 +696,11 @@ impl MachineState {
TrailRef::Ref(Ref::StackCell(fr, sc)) => {
self.and_stack[fr][sc] = Addr::StackCell(fr, sc)
}
TrailRef::AttrVarLink(h, prev_addr) => {
self.heap[h] = HeapCellValue::Addr(prev_addr)
TrailRef::AttrVarHeapLink(h) => {
self.heap[h] = HeapCellValue::Addr(Addr::HeapCell(h));
}
TrailRef::AttrVarListLink(h, l) => {
self.heap[h] = HeapCellValue::Addr(Addr::Lis(l));
}
}
}
@@ -735,13 +744,14 @@ impl MachineState {
let mut i = self.or_stack[b].tr;
while i < self.tr {
let tr_i = self.trail[i].clone();
let tr_i = self.trail[i];
let hb = self.hb;
match tr_i {
TrailRef::Ref(Ref::AttrVar(tr_i))
| TrailRef::Ref(Ref::HeapCell(tr_i))
| TrailRef::AttrVarLink(tr_i, _) => {
| TrailRef::Ref(Ref::HeapCell(tr_i))
| TrailRef::AttrVarHeapLink(tr_i)
| TrailRef::AttrVarListLink(tr_i, _) => {
if tr_i < hb {
i += 1;
} else {
@@ -765,7 +775,7 @@ impl MachineState {
i += 1;
} else {
let tr = self.tr;
let val = self.trail[tr - 1].clone();
let val = self.trail[tr - 1];
self.trail[i] = val;
self.trail.pop();
self.tr -= 1;