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* Optimisation in the // operator: if one of the sets is empty, return 

the other set.
This commit is contained in:
Eelco Dolstra 2010-08-02 16:31:05 +00:00
parent 7af6a2fd71
commit 6d6200f37a
1 changed files with 8 additions and 6 deletions
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14
src/libexpr/eval.cc
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@ -750,13 +750,15 @@ void ExprOpImpl::eval(EvalState & state, Env & env, Value & v)
void ExprOpUpdate::eval(EvalState & state, Env & env, Value & v)
{
Value v2;
state.evalAttrs(env, e1, v2);
state.cloneAttrs(v2, v);
Value v1, v2;
state.evalAttrs(env, e1, v1);
state.evalAttrs(env, e2, v2);
if (v1.attrs->size() == 0) { v = v2; return; }
if (v2.attrs->size() == 0) { v = v1; return; }
state.cloneAttrs(v1, v);
foreach (Bindings::iterator, i, *v2.attrs) {
Attr & a = (*v.attrs)[i->first];
mkCopy(a.value, i->second.value);