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Make MBE expansion more resilient (WIP)

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This commit is contained in:
Florian Diebold
2020-03-13 13:03:31 +01:00
committed by Florian Diebold
parent d3773ec152
commit b973158aeb
10 changed files with 167 additions and 90 deletions
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4
crates/ra_mbe/src/lib.rs
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@@ -30,6 +30,8 @@ pub enum ExpandError {
InvalidRepeat,
}
pub type ExpandResult<T> = (T, Option<ExpandError>);
pub use crate::syntax_bridge::{
ast_to_token_tree, parse_to_token_tree, syntax_node_to_token_tree, token_tree_to_syntax_node,
TokenMap,
@@ -150,7 +152,7 @@ impl MacroRules {
Ok(MacroRules { rules, shift: Shift::new(tt) })
}
pub fn expand(&self, tt: &tt::Subtree) -> Result<tt::Subtree, ExpandError> {
pub fn expand(&self, tt: &tt::Subtree) -> ExpandResult<tt::Subtree> {
// apply shift
let mut tt = tt.clone();
self.shift.shift_all(&mut tt);