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route parsing via TokenSource trait

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This commit is contained in:
Aleksey Kladov 2019-02-20 21:50:07 +03:00
parent 3517c175ac
commit 0c81b9deee
3 changed files with 59 additions and 64 deletions
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50
crates/ra_syntax/src/parsing/parser_impl.rs
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@ -1,5 +1,5 @@
mod event;
mod input;
pub(crate) mod input;
use std::cell::Cell;
@ -11,7 +11,7 @@ use crate::{
parser_api::Parser,
parser_impl::{
event::{Event, EventProcessor},
input::{InputPosition, ParserInput},
input::InputPosition,
},
},
};
@ -39,6 +39,12 @@ pub(super) trait TreeSink {
fn finish(self) -> Self::Tree;
}
pub(super) trait TokenSource {
fn token_kind(&self, pos: InputPosition) -> SyntaxKind;
fn is_token_joint_to_next(&self, pos: InputPosition) -> bool;
fn is_keyword(&self, pos: InputPosition, kw: &str) -> bool;
}
/// Parse a sequence of tokens into the representative node tree
pub(super) fn parse_with<S: TreeSink>(
sink: S,
@ -48,7 +54,7 @@ pub(super) fn parse_with<S: TreeSink>(
) -> S::Tree {
let mut events = {
let input = input::ParserInput::new(text, tokens);
let parser_impl = ParserImpl::new(&input);
let parser_impl = ParserImpl::new(input);
let mut parser_api = Parser(parser_impl);
parser(&mut parser_api);
parser_api.0.into_events()
@ -59,17 +65,17 @@ pub(super) fn parse_with<S: TreeSink>(
/// Implementation details of `Parser`, extracted
/// to a separate struct in order not to pollute
/// the public API of the `Parser`.
pub(super) struct ParserImpl<'t> {
parser_input: &'t ParserInput<'t>,
pub(super) struct ParserImpl<S> {
token_source: S,
pos: InputPosition,
events: Vec<Event>,
steps: Cell<u32>,
}
impl<'t> ParserImpl<'t> {
fn new(inp: &'t ParserInput<'t>) -> ParserImpl<'t> {
impl<S: TokenSource> ParserImpl<S> {
fn new(token_source: S) -> ParserImpl<S> {
ParserImpl {
parser_input: inp,
token_source,
pos: InputPosition::new(),
events: Vec::new(),
steps: Cell::new(0),
@ -82,11 +88,9 @@ impl<'t> ParserImpl<'t> {
}
pub(super) fn current2(&self) -> Option<(SyntaxKind, SyntaxKind)> {
let c1 = self.parser_input.kind(self.pos);
let c2 = self.parser_input.kind(self.pos + 1);
if self.parser_input.token_start_at(self.pos + 1)
== self.parser_input.token_start_at(self.pos) + self.parser_input.token_len(self.pos)
{
let c1 = self.token_source.token_kind(self.pos);
let c2 = self.token_source.token_kind(self.pos + 1);
if self.token_source.is_token_joint_to_next(self.pos) {
Some((c1, c2))
} else {
None
@ -94,14 +98,11 @@ impl<'t> ParserImpl<'t> {
}
pub(super) fn current3(&self) -> Option<(SyntaxKind, SyntaxKind, SyntaxKind)> {
let c1 = self.parser_input.kind(self.pos);
let c2 = self.parser_input.kind(self.pos + 1);
let c3 = self.parser_input.kind(self.pos + 2);
if self.parser_input.token_start_at(self.pos + 1)
== self.parser_input.token_start_at(self.pos) + self.parser_input.token_len(self.pos)
&& self.parser_input.token_start_at(self.pos + 2)
== self.parser_input.token_start_at(self.pos + 1)
+ self.parser_input.token_len(self.pos + 1)
let c1 = self.token_source.token_kind(self.pos);
let c2 = self.token_source.token_kind(self.pos + 1);
let c3 = self.token_source.token_kind(self.pos + 2);
if self.token_source.is_token_joint_to_next(self.pos)
&& self.token_source.is_token_joint_to_next(self.pos + 1)
{
Some((c1, c2, c3))
} else {
@ -114,12 +115,11 @@ impl<'t> ParserImpl<'t> {
let steps = self.steps.get();
assert!(steps <= 10_000_000, "the parser seems stuck");
self.steps.set(steps + 1);
self.parser_input.kind(self.pos + n)
self.token_source.token_kind(self.pos + n)
}
pub(super) fn at_kw(&self, t: &str) -> bool {
self.parser_input.token_text(self.pos) == t
pub(super) fn at_kw(&self, kw: &str) -> bool {
self.token_source.is_keyword(self.pos, kw)
}
/// Start parsing right behind the last event.