1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

extern crate quote;
extern crate proc_macro2;
extern crate proc_macro;

use quote::quote_spanned;

// This can't use the `peg` crate as it would be a circular dependency, but the generated code in grammar.rs
// requires `::peg` paths.
extern crate peg_runtime as peg;

mod ast;
mod tokens;
mod grammar;
mod translate;
mod analysis;

/// The main macro for creating a PEG parser.
/// 
/// For the grammar syntax, see the `peg` crate documentation.
#[proc_macro]
pub fn parser(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    let tokens = tokens::FlatTokenStream::new(input.into());
    let grammar = match grammar::peg::peg_grammar(&tokens) {
        Ok(g) => g,
        Err(err) => {
            let msg = format!("expected {}", err.expected);
            return quote_spanned!(err.location.0=> compile_error!(#msg);).into();
        }
    };

    translate::compile_grammar(&grammar).into()
}