chronlang-parser 0.1.7

use chumsky::{prelude::*, text::{ident, Character}};
use crate::ast::Stmt;

pub fn parser() -> impl Parser<char, Stmt, Error = Simple<char>> {
  let start = just("lang").padded();

  let id = ident()
    .map_with_span(|id, span| (span, id));

  let parent = just("<")
    .padded()
    .ignore_then(
      ident()
        .map_with_span(|p, span| (span, p))
    )
    .or_not();

  let name = just(":")
    .padded()
    .ignore_then(
      filter(|c: &char| c.is_alphanumeric() || c.is_inline_whitespace() || "-()".contains(*c))
        .repeated()
        .at_least(1)
        .map_with_span(|cs, span| (span, cs.iter().collect()))
    )
    .or_not();

  start
    .ignore_then(id)
    .then(parent)
    .then(name)
    .map(|((id, parent), name)| Stmt::Language { id, parent, name })
}

#[cfg(test)]
mod test {
  use super::*;

  #[test]
  fn it_parses_a_language() {
    let src = "lang PA";
    assert_eq!(
      parser().parse(src.to_string()),
      Ok(Stmt::Language { id: (5..7, "PA".to_string()), parent: None, name: None })
    )
  }

  #[test]
  fn it_parses_a_language_with_a_parent() {
    let src = "lang OA < PA";
    assert_eq!(
      parser().parse(src.to_string()),
      Ok(Stmt::Language { id: (5..7, "OA".to_string()), parent: Some((10..12, "PA".to_string())), name: None })
    )
  }

  #[test]
  fn it_parses_a_language_with_a_name() {
    let src = "lang PA: Proto-A";
    assert_eq!(
      parser().parse(src.to_string()),
      Ok(Stmt::Language { id: (5..7, "PA".to_string()), parent: None, name: Some((9..16, "Proto-A".to_string())) })
    )
  }

  #[test]
  fn it_parses_a_language_with_a_parent_and_a_name() {
    let src = "lang OA < PA: Old A";
    assert_eq!(
      parser().parse(src.to_string()),
      Ok(Stmt::Language { id: (5..7, "OA".to_string()), parent: Some((10..12, "PA".to_string())), name: Some((14..19, "Old A".to_string())) })
    )
  }
}