| use proc_macro2; |
| |
| use ast; |
| use attr; |
| use bound; |
| use syn; |
| |
| /// Make generic with all the generics in the input, plus a bound `T: <trait_path>` for each |
| /// generic field type that will be shown. |
| pub fn build_impl_generics<F, G, H>( |
| item: &ast::Input, |
| trait_path: &syn::Path, |
| needs_debug_bound: F, |
| field_bound: G, |
| input_bound: H, |
| ) -> syn::Generics |
| where |
| F: Fn(&attr::Field) -> bool, |
| G: Fn(&attr::Field) -> Option<&[syn::WherePredicate]>, |
| H: Fn(&attr::Input) -> Option<&[syn::WherePredicate]>, |
| { |
| let generics = bound::without_defaults(item.generics); |
| let generics = bound::with_where_predicates_from_fields(item, &generics, field_bound); |
| |
| match input_bound(&item.attrs) { |
| Some(predicates) => bound::with_where_predicates(&generics, predicates), |
| None => bound::with_bound(item, &generics, needs_debug_bound, trait_path), |
| } |
| } |
| |
| /// Construct a name for the inner type parameter that can't collide with any |
| /// type parameters of the item. This is achieved by starting with a base and |
| /// then concatenating the names of all other type parameters. |
| pub fn hygienic_type_parameter(item: &ast::Input, base: &str) -> syn::Ident { |
| let mut typaram = String::with_capacity(150); |
| typaram.push_str(base); |
| let typaram = item.generics.type_params().fold(typaram, |mut acc, ty| { |
| acc.push_str(&format!("{}", &ty.ident)); |
| acc |
| }); |
| |
| syn::Ident::new(&typaram, proc_macro2::Span::call_site()) |
| } |