/*!
Frontend for [WGSL][wgsl] (WebGPU Shading Language).

[wgsl]: https://gpuweb.github.io/gpuweb/wgsl.html
*/

mod error;
mod index;
mod lower;
mod parse;
#[cfg(test)]
mod tests;
mod to_wgsl;

use crate::front::wgsl::error::Error;
use crate::front::wgsl::parse::Parser;
use thiserror::Error;

pub use crate::front::wgsl::error::ParseError;
use crate::front::wgsl::lower::Lowerer;
use crate::Scalar;

pub struct Frontend {
    parser: Parser,
}

impl Frontend {
    pub const fn new() -> Self {
        Self {
            parser: Parser::new(),
        }
    }

    pub fn parse(&mut self, source: &str) -> Result<crate::Module, ParseError> {
        self.inner(source).map_err(|x| x.as_parse_error(source))
    }

    fn inner<'a>(&mut self, source: &'a str) -> Result<crate::Module, Error<'a>> {
        let tu = self.parser.parse(source)?;
        let index = index::Index::generate(&tu)?;
        let module = Lowerer::new(&index).lower(&tu)?;

        Ok(module)
    }
}

pub fn parse_str(source: &str) -> Result<crate::Module, ParseError> {
    Frontend::new().parse(source)
}