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//! JSON query language parser.
#![no_std]

extern crate alloc;

pub mod filter;
mod ops;
pub mod path;
mod token;
mod toplevel;

pub use ops::{MathOp, OrdOp};
use path::Path;
use token::Token;
pub use toplevel::{defs, main, Def, Main};

use alloc::{string::String, string::ToString, vec::Vec};
use chumsky::prelude::*;

type Span = core::ops::Range<usize>;
/// An object with position information.
pub type Spanned<T> = (T, Span);

/// Lex/parse error.
pub type Error = Simple<String>;

fn lex() -> impl Parser<char, Vec<Spanned<Token>>, Error = Simple<char>> {
    let comment = just("#").then(take_until(just('\n'))).padded();

    token::token()
        .padded_by(comment.repeated())
        .map_with_span(|tok, span| (tok, span))
        .padded()
        .repeated()
}

/// Parse a string with a given parser.
///
/// May produce `Some` output even if there were errors.
pub fn parse<T, P>(src: &str, parser: P) -> (Option<T>, Vec<Error>)
where
    P: Parser<Token, T, Error = Simple<Token>> + Clone,
{
    let (tokens, lex_errs) = lex()
        .then_ignore(end())
        .recover_with(skip_then_retry_until([]))
        .parse_recovery(src);

    let (parsed, parse_errs) = if let Some(tokens) = tokens {
        let len = src.chars().count();
        let stream = chumsky::Stream::from_iter(len..len + 1, tokens.into_iter());
        parser.then_ignore(end()).parse_recovery(stream)
    } else {
        (None, Vec::new())
    };

    let lex_errs = lex_errs.into_iter().map(|e| e.map(|c| c.to_string()));
    let parse_errs = parse_errs.into_iter().map(|e| e.map(|tok| tok.to_string()));
    let errs: Vec<_> = lex_errs.chain(parse_errs).collect();

    (parsed, errs)
}