From be03aa5ee79241a6d22a79625e37f2ce5559a345 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Thu, 31 Jan 2019 15:26:01 +0300
Subject: [PATCH] extract tt cursor
---
crates/ra_macros/src/lib.rs | 1 +
crates/ra_macros/src/mbe.rs | 2 +-
crates/ra_macros/src/mbe_parser.rs | 102 ++---------------------------
crates/ra_macros/src/tt_cursor.rs | 92 ++++++++++++++++++++++++++
4 files changed, 101 insertions(+), 96 deletions(-)
create mode 100644 crates/ra_macros/src/tt_cursor.rs
diff --git a/crates/ra_macros/src/lib.rs b/crates/ra_macros/src/lib.rs
index 9485b1c3db6..e35a056ccf8 100644
--- a/crates/ra_macros/src/lib.rs
+++ b/crates/ra_macros/src/lib.rs
@@ -12,5 +12,6 @@ macro_rules! impl_froms {
pub mod tt;
pub mod mbe;
+mod tt_cursor;
mod mbe_parser;
mod mbe_expander;
diff --git a/crates/ra_macros/src/mbe.rs b/crates/ra_macros/src/mbe.rs
index ec811c5f0bf..6a168a1b5e2 100644
--- a/crates/ra_macros/src/mbe.rs
+++ b/crates/ra_macros/src/mbe.rs
@@ -1,6 +1,6 @@
use smol_str::SmolStr;
-use crate::tt::{self, Delimiter};
+use crate::tt::Delimiter;
pub use crate::{
mbe_parser::parse,
diff --git a/crates/ra_macros/src/mbe_parser.rs b/crates/ra_macros/src/mbe_parser.rs
index 93c2d40b4a7..024d3a0404a 100644
--- a/crates/ra_macros/src/mbe_parser.rs
+++ b/crates/ra_macros/src/mbe_parser.rs
@@ -1,99 +1,12 @@
use crate::{tt, mbe};
+use crate::tt_cursor::TtCursor;
/// This module parses a raw `tt::TokenStream` into macro-by-example token
/// stream. This is a *mostly* identify function, expect for handling of
/// `$var:tt_kind` and `$(repeat),*` constructs.
-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 at_punct(&self) -> Option<&'a tt::Punct> {
- match self.current() {
- Some(tt::TokenTree::Leaf(tt::Leaf::Punct(it))) => Some(it),
- _ => None,
- }
- }
-
- fn at_char(&self, char: char) -> bool {
- match self.at_punct() {
- Some(tt::Punct { char: c }) if *c == char => true,
- _ => false,
- }
- }
-
- fn at_ident(&mut self) -> Option<&'a tt::Ident> {
- match self.current() {
- Some(tt::TokenTree::Leaf(tt::Leaf::Ident(i))) => Some(i),
- _ => None,
- }
- }
-
- fn bump(&mut self) {
- self.pos += 1;
- }
-
- fn eat(&mut self) -> Option<&'a tt::TokenTree> {
- match self.current() {
- Some(it) => {
- self.bump();
- Some(it)
- }
- None => None,
- }
- }
-
- fn eat_subtree(&mut self) -> Option<&'a tt::Subtree> {
- match self.current()? {
- tt::TokenTree::Subtree(sub) => {
- self.bump();
- Some(sub)
- }
- _ => return None,
- }
- }
-
- fn eat_punct(&mut self) -> Option<&'a tt::Punct> {
- if let Some(it) = self.at_punct() {
- self.bump();
- return Some(it);
- }
- None
- }
-
- fn eat_ident(&mut self) -> Option<&'a tt::Ident> {
- if let Some(i) = self.at_ident() {
- self.bump();
- return Some(i);
- }
- None
- }
-
- fn expect_char(&mut self, char: char) -> Option<()> {
- if self.at_char(char) {
- self.bump();
- return Some(());
- }
- None
- }
-}
-
pub fn parse(tt: &tt::Subtree) -> Option<mbe::MacroRules> {
- let mut parser = RulesParser::new(tt);
+ let mut parser = TtCursor::new(tt);
let mut rules = Vec::new();
while !parser.is_eof() {
rules.push(parse_rule(&mut parser)?)
@@ -101,7 +14,7 @@ pub fn parse(tt: &tt::Subtree) -> Option<mbe::MacroRules> {
Some(mbe::MacroRules { rules })
}
-fn parse_rule(p: &mut RulesParser) -> Option<mbe::Rule> {
+fn parse_rule(p: &mut TtCursor) -> Option<mbe::Rule> {
let lhs = parse_subtree(p.eat_subtree()?)?;
p.expect_char('=')?;
p.expect_char('>')?;
@@ -111,7 +24,7 @@ fn parse_rule(p: &mut RulesParser) -> Option<mbe::Rule> {
fn parse_subtree(tt: &tt::Subtree) -> Option<mbe::Subtree> {
let mut token_trees = Vec::new();
- let mut p = RulesParser::new(tt);
+ let mut p = TtCursor::new(tt);
while let Some(tt) = p.eat() {
let child: mbe::TokenTree = match tt {
tt::TokenTree::Leaf(leaf) => match leaf {
@@ -142,7 +55,7 @@ fn parse_subtree(tt: &tt::Subtree) -> Option<mbe::Subtree> {
})
}
-fn parse_var(p: &mut RulesParser) -> Option<mbe::Var> {
+fn parse_var(p: &mut TtCursor) -> Option<mbe::Var> {
let ident = p.eat_ident().unwrap();
let text = ident.text.clone();
let kind = if p.at_char(':') {
@@ -150,8 +63,7 @@ fn parse_var(p: &mut RulesParser) -> Option<mbe::Var> {
if let Some(ident) = p.eat_ident() {
Some(ident.text.clone())
} else {
- // ugly as hell :(
- p.pos -= 1;
+ p.rev_bump();
None
}
} else {
@@ -160,7 +72,7 @@ fn parse_var(p: &mut RulesParser) -> Option<mbe::Var> {
Some(mbe::Var { text, kind })
}
-fn parse_repeat(p: &mut RulesParser) -> Option<mbe::Repeat> {
+fn parse_repeat(p: &mut TtCursor) -> Option<mbe::Repeat> {
let subtree = p.eat_subtree().unwrap();
let subtree = parse_subtree(subtree)?;
let sep = p.eat_punct()?;
diff --git a/crates/ra_macros/src/tt_cursor.rs b/crates/ra_macros/src/tt_cursor.rs
new file mode 100644
index 00000000000..380c60b4080
--- /dev/null
+++ b/crates/ra_macros/src/tt_cursor.rs
@@ -0,0 +1,92 @@
+use crate::tt;
+
+pub(crate) struct TtCursor<'a> {
+ subtree: &'a tt::Subtree,
+ pos: usize,
+}
+
+impl<'a> TtCursor<'a> {
+ pub(crate) fn new(subtree: &'a tt::Subtree) -> TtCursor<'a> {
+ TtCursor { subtree, pos: 0 }
+ }
+
+ pub(crate) fn is_eof(&self) -> bool {
+ self.pos == self.subtree.token_trees.len()
+ }
+
+ pub(crate) fn current(&self) -> Option<&'a tt::TokenTree> {
+ self.subtree.token_trees.get(self.pos)
+ }
+
+ pub(crate) fn at_punct(&self) -> Option<&'a tt::Punct> {
+ match self.current() {
+ Some(tt::TokenTree::Leaf(tt::Leaf::Punct(it))) => Some(it),
+ _ => None,
+ }
+ }
+
+ pub(crate) fn at_char(&self, char: char) -> bool {
+ match self.at_punct() {
+ Some(tt::Punct { char: c }) if *c == char => true,
+ _ => false,
+ }
+ }
+
+ pub(crate) fn at_ident(&mut self) -> Option<&'a tt::Ident> {
+ match self.current() {
+ Some(tt::TokenTree::Leaf(tt::Leaf::Ident(i))) => Some(i),
+ _ => None,
+ }
+ }
+
+ pub(crate) fn bump(&mut self) {
+ self.pos += 1;
+ }
+ pub(crate) fn rev_bump(&mut self) {
+ self.pos -= 1;
+ }
+
+ pub(crate) fn eat(&mut self) -> Option<&'a tt::TokenTree> {
+ match self.current() {
+ Some(it) => {
+ self.bump();
+ Some(it)
+ }
+ None => None,
+ }
+ }
+
+ pub(crate) fn eat_subtree(&mut self) -> Option<&'a tt::Subtree> {
+ match self.current()? {
+ tt::TokenTree::Subtree(sub) => {
+ self.bump();
+ Some(sub)
+ }
+ _ => return None,
+ }
+ }
+
+ pub(crate) fn eat_punct(&mut self) -> Option<&'a tt::Punct> {
+ if let Some(it) = self.at_punct() {
+ self.bump();
+ return Some(it);
+ }
+ None
+ }
+
+ pub(crate) fn eat_ident(&mut self) -> Option<&'a tt::Ident> {
+ if let Some(i) = self.at_ident() {
+ self.bump();
+ return Some(i);
+ }
+ None
+ }
+
+ pub(crate) fn expect_char(&mut self, char: char) -> Option<()> {
+ if self.at_char(char) {
+ self.bump();
+ return Some(());
+ }
+ None
+ }
+}