57 lines
1.5 KiB
Rust
57 lines
1.5 KiB
Rust
use super::{
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ast::{Expr, Spanned},
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lexer::Token,
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};
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use chumsky::{prelude::*, Stream};
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use logos::Logos;
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/// Parse source string into a Expr
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pub fn parse(src: &str) -> Result<Vec<Spanned<Expr>>, Vec<Simple<Token<'_>>>> {
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let lexer = Token::lexer(src);
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let len = lexer.source().len();
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parser().parse(Stream::from_iter(len..len + 1, lexer.spanned()))
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}
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fn parser<'a>() -> impl Parser<Token<'a>, Vec<Spanned<Expr<'a>>>, Error = Simple<Token<'a>>> {
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recursive(|expr| {
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let atom = select! {
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Token::Symbol(s) => Expr::Symbol(s.into()),
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Token::Keyword(k) => Expr::Keyword(k.into()),
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Token::String(s) => Expr::String(s.into()),
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Token::Number(n) => Expr::Number(n),
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};
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let list = expr
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.clone()
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.repeated()
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.delimited_by(just(Token::LeftParen), just(Token::RightParen));
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let vector = just(Token::Octothrope)
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.ignore_then(list.clone())
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.map(Expr::Vector);
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let list = list.map(Expr::List);
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let quote = just(Token::Quote)
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.ignore_then(expr)
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.map(Box::new)
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.map(Expr::Quote);
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atom.or(list)
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.or(vector)
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.or(quote)
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.map_with_span(Spanned::new)
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})
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.repeated()
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.then_ignore(end())
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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fn assert_parse<'a>(src: &'a str, expected: &'a [Spanned<Expr<'a>>]) {
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assert_eq!(parse(src).unwrap(), expected);
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}
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}
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