1 extern crate proc_macro; 2 use proc_macro::TokenStream; 3 4 #[proc_macro] make_answer(_item: TokenStream) -> TokenStream5pub fn make_answer(_item: TokenStream) -> TokenStream { 6 assert!(true); 7 loop { 8 println!("{}", "Hello World"); 9 break; 10 } 11 "fn answer() -> u32 { 42 }".parse().unwrap() 12 } 13