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internal: Avoid temporary Vec in MBE #11475

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Merged
merged 1 commit into from
Feb 15, 2022
Merged

internal: Avoid temporary Vec in MBE #11475

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20 changes: 10 additions & 10 deletions crates/mbe/src/expander/matcher.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -437,11 +437,12 @@ fn match_loop_inner<'t>(
let mut new_item = item.clone();
new_item.bindings = bindings_builder.copy(&new_item.bindings);
new_item.dot.next();
let mut vars = Vec::new();
collect_vars(&mut vars, tokens);
for var in vars {
bindings_builder.push_empty(&mut new_item.bindings, &var);
}
collect_vars(
&mut |s| {
bindings_builder.push_empty(&mut new_item.bindings, &s);
},
tokens,
);
cur_items.push(new_item);
}
cur_items.push(MatchState {
Expand Down Expand Up @@ -729,17 +730,16 @@ fn match_meta_var(kind: &str, input: &mut TtIter) -> ExpandResult<Option<Fragmen
input.expect_fragment(fragment).map(|it| it.map(Fragment::Tokens))
}

fn collect_vars(buf: &mut Vec<SmolStr>, pattern: &MetaTemplate) {
fn collect_vars(collector_fun: &mut impl FnMut(SmolStr), pattern: &MetaTemplate) {
for op in pattern.iter() {
match op {
Op::Var { name, .. } => buf.push(name.clone()),
Op::Var { name, .. } => collector_fun(name.clone()),
Op::Leaf(_) => (),
Op::Subtree { tokens, .. } => collect_vars(buf, tokens),
Op::Repeat { tokens, .. } => collect_vars(buf, tokens),
Op::Subtree { tokens, .. } => collect_vars(collector_fun, tokens),
Op::Repeat { tokens, .. } => collect_vars(collector_fun, tokens),
}
}
}

impl MetaTemplate {
fn iter_delimited<'a>(&'a self, delimited: Option<&'a tt::Delimiter>) -> OpDelimitedIter<'a> {
OpDelimitedIter { inner: &self.0, idx: 0, delimited }
Expand Down