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Change TokenSource to iteration based

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This commit is contained in:
Edwin Cheng 2019-05-25 20:31:53 +08:00
parent ef00b5af1c
commit fcb1eef323
8 changed files with 174 additions and 103 deletions
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57
crates/ra_parser/src/parser.rs
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@ -19,15 +19,14 @@ use crate::{
/// "start expression, consume number literal,
/// finish expression". See `Event` docs for more.
pub(crate) struct Parser<'t> {
token_source: &'t dyn TokenSource,
token_pos: usize,
token_source: &'t mut dyn TokenSource,
events: Vec<Event>,
steps: Cell<u32>,
}
impl<'t> Parser<'t> {
pub(super) fn new(token_source: &'t dyn TokenSource) -> Parser<'t> {
Parser { token_source, token_pos: 0, events: Vec::new(), steps: Cell::new(0) }
pub(super) fn new(token_source: &'t mut dyn TokenSource) -> Parser<'t> {
Parser { token_source, events: Vec::new(), steps: Cell::new(0) }
}
pub(crate) fn finish(self) -> Vec<Event> {
@ -49,7 +48,7 @@ impl<'t> Parser<'t> {
let c1 = self.nth(0);
let c2 = self.nth(1);
if self.token_source.is_token_joint_to_next(self.token_pos) {
if self.token_source.current().is_jointed_to_next {
Some((c1, c2))
} else {
None
@ -64,8 +63,8 @@ impl<'t> Parser<'t> {
let c1 = self.nth(0);
let c2 = self.nth(1);
let c3 = self.nth(2);
if self.token_source.is_token_joint_to_next(self.token_pos)
&& self.token_source.is_token_joint_to_next(self.token_pos + 1)
if self.token_source.current().is_jointed_to_next
&& self.token_source.lookahead_nth(1).is_jointed_to_next
{
Some((c1, c2, c3))
} else {
@ -76,6 +75,8 @@ impl<'t> Parser<'t> {
/// Lookahead operation: returns the kind of the next nth
/// token.
pub(crate) fn nth(&self, n: usize) -> SyntaxKind {
assert!(n <= 3);
let steps = self.steps.get();
assert!(steps <= 10_000_000, "the parser seems stuck");
self.steps.set(steps + 1);
@ -86,7 +87,7 @@ impl<'t> Parser<'t> {
let mut i = 0;
loop {
let mut kind = self.token_source.token_kind(self.token_pos + i);
let mut kind = self.token_source.lookahead_nth(i).kind;
if let Some((composited, step)) = self.is_composite(kind, i) {
kind = composited;
i += step;
@ -115,7 +116,7 @@ impl<'t> Parser<'t> {
/// Checks if the current token is contextual keyword with text `t`.
pub(crate) fn at_contextual_kw(&self, kw: &str) -> bool {
self.token_source.is_keyword(self.token_pos, kw)
self.token_source.is_keyword(kw)
}
/// Starts a new node in the syntax tree. All nodes and tokens
@ -130,12 +131,12 @@ impl<'t> Parser<'t> {
/// Advances the parser by one token unconditionally
/// Mainly use in `token_tree` parsing
pub(crate) fn bump_raw(&mut self) {
let mut kind = self.token_source.token_kind(self.token_pos);
let mut kind = self.token_source.current().kind;
// Skip dollars, do_bump will eat these later
let mut i = 0;
while kind == SyntaxKind::L_DOLLAR || kind == SyntaxKind::R_DOLLAR {
kind = self.token_source.token_kind(self.token_pos + i);
kind = self.token_source.lookahead_nth(i).kind;
i += 1;
}
@ -236,7 +237,11 @@ impl<'t> Parser<'t> {
fn do_bump(&mut self, kind: SyntaxKind, n_raw_tokens: u8) {
self.eat_dollars();
self.token_pos += usize::from(n_raw_tokens);
for _ in 0..n_raw_tokens {
self.token_source.bump();
}
self.push_event(Event::Token { kind, n_raw_tokens });
}
@ -249,10 +254,14 @@ impl<'t> Parser<'t> {
// We assume the dollars will not occuried between
// mult-byte tokens
let jn1 = self.token_source.is_token_joint_to_next(self.token_pos + n);
let la2 = self.token_source.token_kind(self.token_pos + n + 1);
let jn2 = self.token_source.is_token_joint_to_next(self.token_pos + n + 1);
let la3 = self.token_source.token_kind(self.token_pos + n + 2);
let first = self.token_source.lookahead_nth(n);
let second = self.token_source.lookahead_nth(n + 1);
let third = self.token_source.lookahead_nth(n + 2);
let jn1 = first.is_jointed_to_next;
let la2 = second.kind;
let jn2 = second.is_jointed_to_next;
let la3 = third.kind;
match kind {
T![.] if jn1 && la2 == T![.] && jn2 && la3 == T![.] => Some((T![...], 3)),
@ -271,9 +280,9 @@ impl<'t> Parser<'t> {
fn eat_dollars(&mut self) {
loop {
match self.token_source.token_kind(self.token_pos) {
match self.token_source.current().kind {
k @ SyntaxKind::L_DOLLAR | k @ SyntaxKind::R_DOLLAR => {
self.token_pos += 1;
self.token_source.bump();
self.push_event(Event::Token { kind: k, n_raw_tokens: 1 });
}
_ => {
@ -286,9 +295,9 @@ impl<'t> Parser<'t> {
pub(crate) fn eat_l_dollars(&mut self) -> usize {
let mut ate_count = 0;
loop {
match self.token_source.token_kind(self.token_pos) {
match self.token_source.current().kind {
k @ SyntaxKind::L_DOLLAR => {
self.token_pos += 1;
self.token_source.bump();
self.push_event(Event::Token { kind: k, n_raw_tokens: 1 });
ate_count += 1;
}
@ -302,9 +311,9 @@ impl<'t> Parser<'t> {
pub(crate) fn eat_r_dollars(&mut self, max_count: usize) -> usize {
let mut ate_count = 0;
loop {
match self.token_source.token_kind(self.token_pos) {
match self.token_source.current().kind {
k @ SyntaxKind::R_DOLLAR => {
self.token_pos += 1;
self.token_source.bump();
self.push_event(Event::Token { kind: k, n_raw_tokens: 1 });
ate_count += 1;
@ -320,12 +329,12 @@ impl<'t> Parser<'t> {
}
pub(crate) fn at_l_dollar(&self) -> bool {
let kind = self.token_source.token_kind(self.token_pos);
let kind = self.token_source.current().kind;
(kind == SyntaxKind::L_DOLLAR)
}
pub(crate) fn at_r_dollar(&self) -> bool {
let kind = self.token_source.token_kind(self.token_pos);
let kind = self.token_source.current().kind;
(kind == SyntaxKind::R_DOLLAR)
}
}