Merge #1138

1138: Add L_DOLLAR and R_DOLLAR r=matklad a=edwin0cheng

As discussion in issue https://github.com/rust-analyzer/rust-analyzer/issues/1132 and PR #1125 , this PR add 2 `Syntax::Kind` : `L_DOLLAR` and `R_DOLLAR` for representing `Delimiter::None` in mbe and proc_marco. By design, It should not affect the final syntax tree, and will be discard in `TreeSink`.

My original idea is handling these 2 tokens case by case, but i found that they will appear in every place in the parser (imagine `tt` matcher). So this PR only handle it in `Parser::do_bump` and `Parser::start`, although It will not fix the `expr` matcher executing order problem in original idea.


Co-authored-by: Edwin Cheng <[email protected]>

1 files changed, 26 insertions, 7 deletions

diff --git a/crates/ra_parser/src/lib.rs b/crates/ra_parser/src/lib.rs
index 3ceeeebd7..56755c394 100644
--- a/crates/ra_parser/src/lib.rs
+++ b/crates/ra_parser/src/lib.rs
@@ -53,20 +53,39 @@ pub trait TreeSink {
     fn error(&mut self, error: ParseError);
 }
 
-/// Parse given tokens into the given sink as a rust file.
-pub fn parse(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
+fn parse_from_tokens<F>(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink, f: F)
+where
+    F: FnOnce(&mut parser::Parser),
+{
     let mut p = parser::Parser::new(token_source);
-    grammar::root(&mut p);
+    f(&mut p);
     let events = p.finish();
     event::process(tree_sink, events);
 }
 
+/// Parse given tokens into the given sink as a rust file.
+pub fn parse(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
+    parse_from_tokens(token_source, tree_sink, grammar::root);
+}
+
 /// Parse given tokens into the given sink as a path
 pub fn parse_path(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
-    let mut p = parser::Parser::new(token_source);
-    grammar::path(&mut p);
-    let events = p.finish();
-    event::process(tree_sink, events);
+    parse_from_tokens(token_source, tree_sink, grammar::path);
+}
+
+/// Parse given tokens into the given sink as a expression
+pub fn parse_expr(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
+    parse_from_tokens(token_source, tree_sink, grammar::expr);
+}
+
+/// Parse given tokens into the given sink as a ty
+pub fn parse_ty(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
+    parse_from_tokens(token_source, tree_sink, grammar::type_);
+}
+
+/// Parse given tokens into the given sink as a pattern
+pub fn parse_pat(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
+    parse_from_tokens(token_source, tree_sink, grammar::pattern);
 }
 
 /// A parsing function for a specific braced-block.