From e28a5e048a9da3091897c86e48bc7d4fb2cf601c Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Thu, 31 Jan 2019 11:25:27 +0300
Subject: parsing scaffold
---
crates/ra_hir/src/macros/mbe.rs | 49 +++++++++++++++++++++++++++++++++++++----
1 file changed, 45 insertions(+), 4 deletions(-)
(limited to 'crates/ra_hir/src/macros')
diff --git a/crates/ra_hir/src/macros/mbe.rs b/crates/ra_hir/src/macros/mbe.rs
index 7af7066fb..2e7f9cbf4 100644
--- a/crates/ra_hir/src/macros/mbe.rs
+++ b/crates/ra_hir/src/macros/mbe.rs
@@ -9,8 +9,8 @@ pub(crate) struct MacroRules {
#[derive(Debug)]
struct Rule {
- lhs: TokenTree,
- rhs: TokenTree,
+ lhs: Subtree,
+ rhs: Subtree,
}
#[derive(Debug)]
@@ -75,6 +75,47 @@ struct Var {
text: SmolStr,
}
-pub(crate) fn parse(tt: &tt::Subtree) -> MacroRules {
- MacroRules { rules: Vec::new() }
+pub(crate) fn parse(tt: &tt::Subtree) -> Option<MacroRules> {
+ let mut parser = RulesParser::new(tt);
+ let mut rules = Vec::new();
+ while !parser.is_eof() {
+ rules.push(parse_rule(&mut parser)?)
+ }
+ Some(MacroRules { rules })
+}
+
+fn parse_rule(p: &mut RulesParser) -> Option<Rule> {
+ let lhs = match p.current()? {
+ tt::TokenTree::Subtree(sub) => parse_subtree(sub)?,
+ _ => return None,
+ };
+ let rhs = unimplemented!();
+ Some(Rule { lhs, rhs })
+}
+
+fn parse_subtree(tt: &tt::Subtree) -> Option<Subtree> {
+ unimplemented!()
+}
+
+struct RulesParser<'a> {
+ subtree: &'a tt::Subtree,
+ pos: usize,
+}
+
+impl<'a> RulesParser<'a> {
+ fn new(subtree: &'a tt::Subtree) -> RulesParser<'a> {
+ RulesParser { subtree, pos: 0 }
+ }
+
+ fn is_eof(&self) -> bool {
+ self.pos == self.subtree.token_trees.len()
+ }
+
+ fn current(&self) -> Option<&'a tt::TokenTree> {
+ self.subtree.token_trees.get(self.pos)
+ }
+
+ fn bump(&mut self) {
+ self.pos += 1;
+ }
}
--
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