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"Fix" mbe to work with decomposed tokens

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We regressed $i * 2 where $i = 1 + 1, need to fix that!
This commit is contained in:
Aleksey Kladov
2019-09-10 14:27:08 +03:00
parent 40170885e7
commit 1c5800dee8
6 changed files with 46 additions and 84 deletions
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50
crates/ra_mbe/src/mbe_expander.rs
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@@ -339,21 +339,13 @@ fn expand_subtree(
template: &crate::Subtree,
ctx: &mut ExpandCtx,
) -> Result<tt::Subtree, ExpandError> {
let token_trees = template
.token_trees
.iter()
.map(|it| expand_tt(it, ctx))
.filter(|it| {
// Filter empty subtree
if let Ok(tt::TokenTree::Subtree(subtree)) = it {
subtree.delimiter != tt::Delimiter::None || !subtree.token_trees.is_empty()
} else {
true
}
})
.collect::<Result<Vec<_>, ExpandError>>()?;
let mut buf: Vec<tt::TokenTree> = Vec::new();
for tt in template.token_trees.iter() {
let tt = expand_tt(tt, ctx)?;
push_tt(&mut buf, tt);
}
Ok(tt::Subtree { token_trees, delimiter: template.delimiter })
Ok(tt::Subtree { delimiter: template.delimiter, token_trees: buf })
}
/// Reduce single token subtree to single token
@@ -377,7 +369,7 @@ fn expand_tt(
let res: tt::TokenTree = match template {
crate::TokenTree::Subtree(subtree) => expand_subtree(subtree, ctx)?.into(),
crate::TokenTree::Repeat(repeat) => {
let mut token_trees: Vec<tt::TokenTree> = Vec::new();
let mut buf: Vec<tt::TokenTree> = Vec::new();
ctx.nesting.push(0);
// Dirty hack to make macro-expansion terminate.
// This should be replaced by a propper macro-by-example implementation
@@ -418,23 +410,23 @@ fn expand_tt(
let idx = ctx.nesting.pop().unwrap();
ctx.nesting.push(idx + 1);
token_trees.push(reduce_single_token(t));
push_subtree(&mut buf, t);
if let Some(ref sep) = repeat.separator {
match sep {
crate::Separator::Ident(ident) => {
has_seps = 1;
token_trees.push(tt::Leaf::from(ident.clone()).into());
buf.push(tt::Leaf::from(ident.clone()).into());
}
crate::Separator::Literal(lit) => {
has_seps = 1;
token_trees.push(tt::Leaf::from(lit.clone()).into());
buf.push(tt::Leaf::from(lit.clone()).into());
}
crate::Separator::Puncts(puncts) => {
has_seps = puncts.len();
for punct in puncts {
token_trees.push(tt::Leaf::from(*punct).into());
buf.push(tt::Leaf::from(*punct).into());
}
}
}
@@ -450,16 +442,16 @@ fn expand_tt(
ctx.nesting.pop().unwrap();
for _ in 0..has_seps {
token_trees.pop();
buf.pop();
}
if crate::RepeatKind::OneOrMore == repeat.kind && counter == 0 {
return Err(ExpandError::UnexpectedToken);
}
// Check if it is a singel token subtree without any delimiter
// Check if it is a single token subtree without any delimiter
// e.g {Delimiter:None> ['>'] /Delimiter:None>}
reduce_single_token(tt::Subtree { token_trees, delimiter: tt::Delimiter::None })
reduce_single_token(tt::Subtree { delimiter: tt::Delimiter::None, token_trees: buf })
}
crate::TokenTree::Leaf(leaf) => match leaf {
crate::Leaf::Ident(ident) => {
@@ -586,3 +578,17 @@ mod tests {
expand_rule(&rules.rules[0], &invocation_tt)
}
}
fn push_tt(buf: &mut Vec<tt::TokenTree>, tt: tt::TokenTree) {
match tt {
tt::TokenTree::Subtree(tt) => push_subtree(buf, tt),
_ => buf.push(tt),
}
}
fn push_subtree(buf: &mut Vec<tt::TokenTree>, tt: tt::Subtree) {
match tt.delimiter {
tt::Delimiter::None => buf.extend(tt.token_trees),
_ => buf.push(tt.into()),
}
}