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#![doc(html_root_url = "https://docs.rs/quit_macros/*")]
#![forbid(unsafe_code)]
#![warn(unused_results)]
#[allow(unused_extern_crates)]
extern crate proc_macro;
use std::fmt::Display;
use proc_macro::TokenStream;
use quote::quote;
use quote::ToTokens;
use syn::parse_macro_input;
use syn::Error as SynError;
use syn::ItemFn;
#[inline]
#[proc_macro_attribute]
pub fn main(args: TokenStream, item: TokenStream) -> TokenStream {
if let Some(arg) = args.into_iter().next() {
return SynError::new(arg.span().into(), "arguments are not accepted")
.to_compile_error()
.into();
}
let input = parse_macro_input!(item as ItemFn);
let signature = &input.sig;
let name = &signature.ident;
if name != "main" {
return error(name, "`quit::main` can only be attached to `main`");
}
let attrs = &input.attrs;
let visibility = &input.vis;
let body = &input.block;
return quote! {
#(#attrs)*
#visibility #signature {
match ::std::panic::catch_unwind(|| { #body }) {
Ok(result) => result,
Err(payload) => {
if let Some(&::quit::_ExitCode(exit_code)) =
payload.downcast_ref()
{
::std::process::exit(exit_code);
};
::std::panic::resume_unwind(payload);
},
}
}
}
.into();
fn error<TMessage, TTokens>(
tokens: TTokens,
message: TMessage,
) -> TokenStream
where
TMessage: Display,
TTokens: ToTokens,
{
SynError::new_spanned(tokens, message)
.to_compile_error()
.into()
}
}