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extern crate proc_macro;
use crate::proc_macro::TokenStream;
use proc_macro2;
use quote::{format_ident, quote};
use syn;
#[proc_macro_derive(Identifiers)]
pub fn identifiers_derive(input: TokenStream) -> TokenStream {
let ast = syn::parse(input).unwrap();
impl_identifiers(&ast)
}
fn impl_identifiers(ast: &syn::DeriveInput) -> TokenStream {
let name = &ast.ident;
let struct_name = format_ident! {"{}Identifiers", name};
let vis = &ast.vis;
let methods = match &ast.data {
syn::Data::Struct(s) => get_identifiers_methods(&s.fields, vis),
_ => unreachable!(),
};
let gen = quote! {
#vis struct #struct_name {}
impl #name {
#(#methods)*
}
};
gen.into()
}
fn get_identifiers_methods(
fields: &syn::Fields,
vis: &syn::Visibility,
) -> Vec<proc_macro2::TokenStream> {
let mut res = Vec::new();
for field in fields.iter() {
if let syn::Visibility::Public(_) = field.vis {
if let Some(ident) = &field.ident {
let fun_name = format_ident!("{}_n", ident);
let quote_ident = format!("{}", ident);
let fun = quote! {
#vis fn #fun_name() -> String {
String::from(#quote_ident)
}
};
res.push(fun);
};
};
}
res
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn it_works() {
assert_eq!(2 + 2, 4);
}
}