bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/parser/src/lib.rs')
-rw-r--r--crates/parser/src/lib.rs24
1 files changed, 24 insertions, 0 deletions
diff --git a/crates/parser/src/lib.rs b/crates/parser/src/lib.rs
index 841d2aa4e9..f0b93c4511 100644
--- a/crates/parser/src/lib.rs
+++ b/crates/parser/src/lib.rs
@@ -41,6 +41,30 @@ pub use crate::{
syntax_kind::SyntaxKind,
};
+/// Parse a syntactic construct at the *start* of the input.
+///
+/// This is used by macro-by-example parser to implement things like `$i:item`.
+///
+/// Note that this is generally non-optional -- the result is intentionally not
+/// `Option<Output>`. The way MBE work, by the time we *try* to parse `$e:expr`
+/// we already commit to expression. In other words, this API by design can't be
+/// used to implement "rollback and try another alternative" logic.
+pub enum PrefixEntryPoint {
+ Vis,
+}
+
+impl PrefixEntryPoint {
+ pub fn parse(self, input: &Input) -> Output {
+ let entry_point: fn(&'_ mut parser::Parser) = match self {
+ PrefixEntryPoint::Vis => grammar::entry::prefix::vis,
+ };
+ let mut p = parser::Parser::new(input);
+ entry_point(&mut p);
+ let events = p.finish();
+ event::process(events)
+ }
+}
+
/// rust-analyzer parser allows you to choose one of the possible entry points.
///
/// The primary consumer of this API are declarative macros, `$x:expr` matchers