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Reduce re-allocations in eval

This commit is contained in:
greg 2017-01-05 03:47:52 -08:00
parent 8651839a66
commit dc81d237c5
1 changed files with 10 additions and 8 deletions
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18
src/eval.rs
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@ -165,17 +165,18 @@ impl<'a> Evaluator<'a> {
Some(expr) => (expr, None), Some(expr) => (expr, None),
} }
} }
BinExp(op, box left, box right) => { BinExp(op, mut left, mut right) => {
if right.is_reducible() { if right.is_reducible() {
let new = self.reduce_expr(right); let mut side_effect = None;
return (BinExp(op, Box::new(left), Box::new(new.0)), new.1); take_mut::take(right.as_mut(), |expr| { let (a, b) = self.reduce_expr(expr); side_effect = b; a});
return (BinExp(op, left, right), side_effect);
} }
// special case for variable assignment // special case for variable assignment
if *op == "=" { if *op == "=" {
match left { match *left {
Variable(var) => { Variable(var) => {
let binding = SideEffect::AddBinding(var, right); let binding = SideEffect::AddBinding(var, *right);
return (Null, Some(binding)); return (Null, Some(binding));
} }
_ => return (Null, None), _ => return (Null, None),
@ -183,10 +184,11 @@ impl<'a> Evaluator<'a> {
} }
if left.is_reducible() { if left.is_reducible() {
let new = self.reduce_expr(left); let mut side_effect = None;
(BinExp(op, Box::new(new.0), Box::new(right)), new.1) take_mut::take(left.as_mut(), |expr| { let (a, b) = self.reduce_expr(expr); side_effect = b; a});
(BinExp(op, left, right), side_effect)
} else { } else {
(self.reduce_binop(op, left, right), None) //can assume both arguments are maximally reduced (self.reduce_binop(op, *left, *right), None) //can assume both arguments are maximally reduced
} }
} }
Call(name, mut args) => { Call(name, mut args) => {