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Clean up grammar! code generation

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This commit is contained in:
Chris Mounce
2025-05-26 01:52:04 -07:00
parent 2a935840fd
commit ff9d471e00
1 changed files with 11 additions and 42 deletions
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peg_macro/src/lib.rs
+11 -42
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@@ -1,4 +1,3 @@
use itertools::{Itertools, Position};
use proc_macro::TokenStream;
use quote::quote;
use syn::{
@@ -93,32 +92,19 @@ impl Term {
p.literal(#lit_str)
},
Term::Sequence(terms) => {
let parts: Vec<_> = terms
let expr = terms
.iter()
.with_position()
.map(|(pos, term)| {
let code = term.generate_wrapped_code();
match pos {
Position::First => quote! {
let result = #code;
if !result {
return false;
}
},
Position::Middle => quote! {
let result = #code;
if !result {
p.restore(save);
return false;
}
},
_ => code,
}
})
.collect();
.map(|t| t.generate_wrapped_code())
.reduce(|x, y| quote! { #x && #y })
.unwrap();
quote! {
let save = p.save();
#(#parts)*
if #expr {
true
} else {
p.restore(save);
false
}
}
}
Term::Choice(terms) => terms
@@ -133,9 +119,7 @@ impl Term {
let code = self.generate_code();
match self {
Term::Sequence(_) | Term::Choice(_) => quote! {
(|| {
#code
})()
{ #code }
},
_ => code,
}
@@ -175,24 +159,9 @@ pub fn grammar(ts: TokenStream) -> TokenStream {
.iter()
.map(|r| {
let fn_name = &r.name;
// // Generate a string for debugging
// fn term2str(t: &Term) -> String {
// match t {
// Term::Rule(ident) => format!("rule {}", ident.to_string()),
// Term::Literal(lit_str) => format!("literal \"{}\"", lit_str.value()),
// Term::Sequence(terms) => {
// let parts: Vec<_> = terms.iter().map(term2str).collect();
// format!("sequence [{}]", parts.join(", "))
// }
// }
// }
// let text = format!("I'm generated! ({})", term2str(&r.definition));
let generated = r.definition.generate_code();
quote! {
fn #fn_name(p: &mut crate::peg::ParseState) -> bool {
// println!(#text.into());
#generated
}
}