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#![feature(proc_macro_hygiene)]
#![feature(external_doc)]
#![doc(include = "../README.md")]
extern crate proc_macro;
extern crate proc_macro2;
mod resyn;
use proc_macro::TokenStream;
use quote::quote;
use syn;
#[proc_macro]
pub fn named_return(item: TokenStream) -> TokenStream {
let input = syn::parse_macro_input!(item as resyn::item_fn::ItemFn);
let vis = &input.vis;
let constness = &input.constness;
let unsafety = &input.unsafety;
let ident = &input.ident;
let decl = &input.decl;
let block = &input.block;
let generics = &decl.generics;
let inputs = &decl.inputs;
let _output = &decl.output;
let output_simple: syn::ReturnType = decl.output.clone().into();
type Cp<T> = syn::punctuated::Punctuated<T, syn::token::Comma>;
use resyn::item_fn::fn_decl::return_type::Captures;
let captures: Option<Captures> = decl.output.clone().into();
let (cap_names, cap_types): (Option<Cp<syn::Pat>>, Option<Cp<syn::Type>>) = match captures {
Some(ref caps) => {
use syn::punctuated::Pair;
let (names, types) = caps
.iter()
.map(|arg_cap| {
let name = Pair::new(
arg_cap.pat.clone(),
Some(syn::token::Comma {
spans: arg_cap.colon_token.spans,
}),
);
let ty = Pair::new(
arg_cap.ty.clone(),
Some(syn::token::Comma {
spans: arg_cap.colon_token.spans,
}),
);
(name, ty)
})
.unzip();
(Some(names), Some(types))
}
None => (None, None),
};
let block_prefix = if captures.is_some() {
Some(quote!(let (#cap_names) : (#cap_types) ;))
} else {
None
};
let new_block = if block_prefix.is_some() {
quote!({
#block_prefix
#block
})
} else {
quote!(#block)
};
let reparsed = quote! {
#vis #constness #unsafety fn #ident #generics ( #inputs ) #output_simple #new_block
};
let tokens = quote! {
#reparsed
};
tokens.into()
}
#[proc_macro_attribute]
pub fn named_return_attr(_attr: TokenStream, item: TokenStream) -> TokenStream {
named_return(item)
}