deimos-lang/ast-generator/src/build_fn/leaf_enum_build_fn.rs
2025-09-25 18:43:05 -05:00

31 lines
1.1 KiB
Rust

use crate::deserialize::util::{make_build_fn_name, make_build_pair};
use crate::spec::leaf_enum_spec::LeafEnumBuildSpec;
use proc_macro2::TokenStream;
use quote::{format_ident, quote};
pub fn make_leaf_enum_build_fn(leaf_enum_build_spec: &LeafEnumBuildSpec) -> TokenStream {
let build_fn_ident = format_ident!("{}", make_build_fn_name(leaf_enum_build_spec.build()));
let pair_ident = format_ident!("{}", make_build_pair(leaf_enum_build_spec.build()));
let return_type_ident = format_ident!("{}", leaf_enum_build_spec.build());
let rule_branches = leaf_enum_build_spec
.rules()
.map(|leaf_enum_rule| {
let rule_ident = format_ident!("{}", leaf_enum_rule);
quote! {
Rule::#rule_ident => #return_type_ident::#rule_ident
}
})
.collect::<Vec<_>>();
quote! {
fn #build_fn_ident(file_id: usize, #pair_ident: Pair<Rule>) -> #return_type_ident {
let inner_pair = #pair_ident.into_inner().next().unwrap();
match inner_pair.as_rule() {
#(#rule_branches,)*
_ => unreachable!()
}
}
}
}