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extern crate proc_macro; use proc_macro::TokenStream; use quote::quote; #[proc_macro_derive(Display)] pub fn display_derive(input: TokenStream) -> TokenStream { let ast = syn::parse(input).expect("TokenStream could not be parsed"); impl_display_derive(&ast) } fn impl_display_derive(ast: &syn::DeriveInput) -> TokenStream { let name = &ast.ident; let gen = quote! { impl Display for #name { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { write!(f, "{:?}", self) } } }; gen.into() }