iowo/crates/pawarser/src/lib.rs

#![feature(iter_collect_into)]
pub mod parser {
    pub mod input {
        use enumset::{EnumSet, EnumSetType};

        struct Input<'src, 'toks, SyntaxKind: EnumSetType + Into<rowan::SyntaxKind>> {
            raw: &'toks Vec<(SyntaxKind, &'src str)>,
            // enumset of meaningless tokens
            semantically_meaningless: EnumSet<SyntaxKind>,
            // indices of non-meaningless tokens
            meaningful_toks: Vec<usize>,
        }

        impl<'src, 'toks, SyntaxKind: EnumSetType + Into<rowan::SyntaxKind>>
            Input<'src, 'toks, SyntaxKind>
        {
            pub fn new(
                raw_toks: &'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,
                }
            }
        }
    }
}