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By pass unbind $var while mbe expanding

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This commit is contained in:
Edwin Cheng 2019-05-03 23:23:21 +08:00
parent e8e46100d6
commit 31909cc7d7
3 changed files with 39 additions and 7 deletions
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2
crates/ra_mbe/src/lib.rs
View File

@ -154,4 +154,4 @@ pub(crate) struct Var {
}
#[cfg(test)]
mod tests;
mod tests;

42
crates/ra_mbe/src/mbe_expander.rs
View File

@ -84,6 +84,10 @@ enum Binding {
}
impl Bindings {
fn contains(&self, name: &SmolStr) -> bool {
self.inner.contains_key(name)
}
fn get(&self, name: &SmolStr, nesting: &[usize]) -> Result<&tt::TokenTree, ExpandError> {
let mut b = self
.inner
@ -458,6 +462,33 @@ fn expand_tt(
// FIXME: Properly handle $crate token
tt::Leaf::from(tt::Ident { text: "$crate".into(), id: TokenId::unspecified() })
.into()
} else if !ctx.bindings.contains(&v.text) {
// Note that it is possible to have a `$var` inside a macro which is not bound.
// For example:
// ```
// macro_rules! foo {
// ($a:ident, $b:ident, $c:tt) => {
// macro_rules! bar {
// ($bi:ident) => {
// fn $bi() -> u8 {$c}
// }
// }
// }
// ```
// We just treat it a normal tokens
tt::Subtree {
delimiter: tt::Delimiter::None,
token_trees: vec![
tt::Leaf::from(tt::Punct { char: '$', spacing: tt::Spacing::Alone })
.into(),
tt::Leaf::from(tt::Ident {
text: v.text.clone(),
id: TokenId::unspecified(),
})
.into(),
],
}
.into()
} else {
let tkn = ctx.bindings.get(&v.text, &ctx.nesting)?.clone();
ctx.var_expanded = true;
@ -484,11 +515,12 @@ mod tests {
#[test]
fn test_expand_rule() {
assert_err(
"($i:ident) => ($j)",
"foo!{a}",
ExpandError::BindingError(String::from("could not find binding `j`")),
);
// FIXME: The missing $var check should be in parsing phase
// assert_err(
// "($i:ident) => ($j)",
// "foo!{a}",
// ExpandError::BindingError(String::from("could not find binding `j`")),
// );
assert_err(
"($($i:ident);*) => ($i)",

2
crates/ra_mbe/src/tests.rs
View File

@ -952,7 +952,7 @@ macro_rules! foo {
MacroKind::Items,
&rules,
r#"foo!(x,y, 1);"#,
r#"macro_rules ! bar {(bi : ident) => {fn bi () -> u8 {1}}} bar ! (x) ; fn y () -> u8 {1}"#,
r#"macro_rules ! bar {($ bi : ident) => {fn $ bi () -> u8 {1}}} bar ! (x) ; fn y () -> u8 {1}"#,
);
}