iowo/crates/pawarser/src/parser/input.rs

67 lines
2 KiB
Rust

use enumset::{EnumSet, EnumSetType};
use super::SyntaxElement;
pub struct Input<'src, SyntaxKind: SyntaxElement> {
raw: Vec<(SyntaxKind, &'src str)>,
// enumset of meaningless tokens
semantically_meaningless: EnumSet<SyntaxKind>,
// indices of non-meaningless tokens
meaningful_toks: Vec<usize>,
}
impl<'src, SyntaxKind: SyntaxElement> Input<'src, SyntaxKind> {
pub fn new(
raw_toks: Vec<(SyntaxKind, &'src str)>,
meaningless: Option<EnumSet<SyntaxKind>>,
) -> Self {
let mut meaningful_toks = Vec::new();
if let Some(meaningless) = meaningless {
let meaningful_toks = raw_toks
.iter()
.enumerate()
.filter_map(|(i, tok)| (!meaningless.contains(tok.0)).then_some(i))
.collect_into(&mut meaningful_toks);
}
Self {
raw: raw_toks,
semantically_meaningless: meaningless.unwrap_or_default(),
meaningful_toks,
}
}
pub fn kind(&self, idx: usize) -> SyntaxKind {
let Some(meaningful_idx) = self.meaningful_toks.get(idx) else {
return SyntaxKind::SYNTAX_EOF;
};
self.raw.get(*meaningful_idx).unwrap().0
}
pub fn preceding_meaningless(&self, idx: usize) -> usize {
assert!(self.meaningful_toks.len() > idx);
if idx == 0 {
// maybe should be `self.meaningful_toks[idx]` instead??
1
} else {
self.meaningful_toks[idx] - self.meaningful_toks[idx - 1]
}
}
/// get the count of meaningless tokens at the end of the file.
pub fn meaningless_tail_len(&self) -> usize {
self.raw.len() - (self.meaningful_toks.last().unwrap() + 1)
}
pub fn dissolve(self) -> (Vec<(SyntaxKind, &'src str)>, EnumSet<SyntaxKind>) {
let Self {
raw,
semantically_meaningless,
..
} = self;
(raw, semantically_meaningless)
}
}