Amo/src/parser/declaration.rs

use std::mem::{Discriminant, discriminant};

use crate::token::Token;

use super::{Parsable, WrappedLexer, ParseError, absorb_token_or_error, expr::Expr};

#[derive(Debug)]
pub struct Declaration {
	name: String,
	type_: Expr,
	name2: String,
	args: Vec<String>,
	value: Expr,
}

impl Parsable for Declaration {
	fn expected() -> (Vec<Discriminant<Token>>, bool) {
		(vec![
			discriminant(&Token::Symbol("".to_string())),
		], false)
	}
	fn parse(l: &mut WrappedLexer) -> Result<Self, ParseError> {
		let span = l.span();
		match l.monch() {
			// Symbol Colon <full_type> DeclarationStart Symbol { Symbol } Assign <expr>
			Token::Symbol(name) => {
				absorb_token_or_error(l, discriminant(&Token::Colon))?;
				let type_ = Expr::parse(l)?;
				absorb_token_or_error(l, discriminant(&Token::DeclarationStart))?;
				let name2 = String::parse(l)?;
				let args = Vec::parse(l)?;
				absorb_token_or_error(l, discriminant(&Token::Assign))?;
				let value = Expr::parse(l)?;
				Ok(Self {
					name,
					name2,
					args,
					type_,
					value,
				})
	 		},
			_ => {
				Err(ParseError {
					expected: Self::expected().0,
					location: span,
				})
			}
		}
	}
}