logos_codegen/generator/
rope.rs

1use proc_macro2::TokenStream;
2use quote::quote;
3
4use crate::generator::{Context, Generator};
5use crate::graph::Rope;
6
7impl Generator<'_> {
8    pub fn generate_rope(&mut self, rope: &Rope, mut ctx: Context) -> TokenStream {
9        let miss = ctx.miss(rope.miss.first(), self);
10        let read = ctx.read(rope.pattern.len());
11        let then = self.goto(rope.then, ctx.advance(rope.pattern.len()));
12
13        let pat = match rope.pattern.to_bytes() {
14            Some(bytes) => byte_slice_literal(&bytes),
15            None => {
16                let ranges = rope.pattern.iter();
17
18                quote!([#(#ranges),*])
19            }
20        };
21
22        quote! {
23            match #read {
24                Some(#pat) => #then,
25                _ => #miss,
26            }
27        }
28    }
29}
30
31fn byte_slice_literal(bytes: &[u8]) -> TokenStream {
32    if bytes.iter().any(|&b| !(0x20..0x7F).contains(&b)) {
33        return quote!(&[#(#bytes),*]);
34    }
35
36    let slice = std::str::from_utf8(bytes).unwrap();
37
38    syn::parse_str(&format!("b{:?}", slice)).unwrap()
39}
logos_codegen/generator/rope.rs

logos_codegen/generator/
rope.rs
