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|
use parser::input::{InputPosition, ParserInput};
use parser::event::Event;
use SyntaxKind;
use syntax_kinds::{EOF, TOMBSTONE};
/// Implementation details of `Parser`, extracted
/// to a separate struct in order not to pollute
/// the public API of the `Parser`.
pub(crate) struct ParserImpl<'t> {
inp: &'t ParserInput<'t>,
pos: InputPosition,
events: Vec<Event>,
}
impl<'t> ParserImpl<'t> {
pub(crate) fn new(inp: &'t ParserInput<'t>) -> ParserImpl<'t> {
ParserImpl {
inp,
pos: InputPosition::new(),
events: Vec::new(),
}
}
pub(crate) fn into_events(self) -> Vec<Event> {
assert_eq!(self.nth(0), EOF);
self.events
}
pub(super) fn nth(&self, n: u32) -> SyntaxKind {
self.inp.kind(self.pos + n)
}
pub(super) fn at_kw(&self, t: &str) -> bool {
self.inp.text(self.pos) == t
}
pub(super) fn start(&mut self) -> u32 {
let pos = self.events.len() as u32;
self.event(Event::Start {
kind: TOMBSTONE,
forward_parent: None,
});
pos
}
pub(super) fn bump(&mut self) {
let kind = self.nth(0);
if kind == EOF {
return;
}
self.do_bump(kind);
}
pub(super) fn bump_remap(&mut self, kind: SyntaxKind) {
if self.nth(0) == EOF {
// TODO: panic!?
return;
}
self.do_bump(kind);
}
fn do_bump(&mut self, kind: SyntaxKind) {
self.pos += 1;
self.event(Event::Token {
kind,
n_raw_tokens: 1,
});
}
pub(super) fn error(&mut self, msg: String) {
self.event(Event::Error { msg })
}
pub(super) fn complete(&mut self, pos: u32, kind: SyntaxKind) {
match self.events[pos as usize] {
Event::Start {
kind: ref mut slot, ..
} => {
*slot = kind;
}
_ => unreachable!(),
}
self.event(Event::Finish);
}
pub(super) fn abandon(&mut self, pos: u32) {
let idx = pos as usize;
if idx == self.events.len() - 1 {
match self.events.pop() {
Some(Event::Start {
kind: TOMBSTONE,
forward_parent: None,
}) => (),
_ => unreachable!(),
}
}
}
pub(super) fn precede(&mut self, pos: u32) -> u32 {
let new_pos = self.start();
match self.events[pos as usize] {
Event::Start {
ref mut forward_parent,
..
} => {
*forward_parent = Some(new_pos - pos);
}
_ => unreachable!(),
}
new_pos
}
fn event(&mut self, event: Event) {
self.events.push(event)
}
}
|
