rishi/scryer-prolog
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realize full cheney in copier.rs

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This commit is contained in:
Mark Thom
2018-07-29 18:38:26 -06:00
parent 1b025d409f
commit 1ce527d179
1 changed files with 12 additions and 14 deletions
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20
src/prolog/copier.rs
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@@ -1,7 +1,6 @@
use prolog::and_stack::*;
use prolog::ast::*;
use std::collections::HashMap;
use std::ops::IndexMut;
type Trail = Vec<(Ref, HeapCellValue)>;
@@ -40,11 +39,6 @@ pub(crate) trait CopierTarget
let mut scan = self.source();
let old_h = self.threshold();
// Lists have a compressed representation as structures,
// removing the need for NamedStr, so we use a redirection
// table for copying lists.
let mut list_redirect = HashMap::new();
self.push(HeapCellValue::Addr(addr));
while scan < self.threshold() {
@@ -54,15 +48,16 @@ pub(crate) trait CopierTarget
HeapCellValue::Addr(a) =>
match a.clone() {
Addr::Lis(a) => {
if let Some(idx) = list_redirect.get(&a) {
self[scan] = HeapCellValue::Addr(Addr::Lis(*idx));
if let HeapCellValue::Addr(Addr::Lis(b)) = self[a].clone() {
if b >= old_h {
self[scan] = HeapCellValue::Addr(Addr::Lis(b));
scan += 1;
continue;
}
}
list_redirect.insert(a, self.threshold());
self[scan] = HeapCellValue::Addr(Addr::Lis(self.threshold()));
let threshold = self.threshold();
self[scan] = HeapCellValue::Addr(Addr::Lis(threshold));
let hcv = self[a].clone();
self.push(hcv);
@@ -70,6 +65,9 @@ pub(crate) trait CopierTarget
let hcv = self[a+1].clone();
self.push(hcv);
trail.push((Ref::HeapCell(a), self[a].clone()));
self[a] = HeapCellValue::Addr(Addr::Lis(threshold));
scan += 1;
},
Addr::HeapCell(_) | Addr::StackCell(_, _) => {