educe/trait_handlers/debug/
common.rs

1use quote::quote;
2use syn::{DeriveInput, Path, Type};
3
4#[inline]
5pub(crate) fn create_debug_map_builder() -> proc_macro2::TokenStream {
6    quote!(
7        #[allow(non_camel_case_types)] // We're using __ to help avoid clashes.
8        struct Educe__RawString(&'static str);
9
10        impl ::core::fmt::Debug for Educe__RawString {
11            #[inline]
12            fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
13                f.write_str(self.0)
14            }
15        }
16
17        let mut builder = f.debug_map();
18    )
19}
20
21#[inline]
22pub(crate) fn create_format_arg(
23    ast: &DeriveInput,
24    field_ty: &Type,
25    format_method: &Path,
26    field_expr: proc_macro2::TokenStream,
27) -> proc_macro2::TokenStream {
28    let ty_ident = &ast.ident;
29
30    // We use the complete original generics, not filtered by field,
31    // and include a PhantomData<Self> in our wrapper struct to use the generics.
32    //
33    // This avoids having to try to calculate the right *subset* of the generics
34    // relevant for this field, which is nontrivial and maybe impossible.
35    let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
36
37    quote!(
38        let arg = {
39            #[allow(non_camel_case_types)] // We're using __ to help avoid clashes.
40            struct Educe__DebugField<V, M>(V, ::core::marker::PhantomData<M>);
41
42            impl #impl_generics ::core::fmt::Debug
43                for Educe__DebugField<&#field_ty, #ty_ident #ty_generics>
44                #where_clause
45            {
46                #[inline]
47                fn fmt(&self, educe__f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
48                    #format_method(self.0, educe__f)
49                }
50            }
51
52            Educe__DebugField(#field_expr, ::core::marker::PhantomData::<Self>)
53        };
54    )
55}
educe/trait_handlers/debug/common.rs

educe/trait_handlers/debug/
common.rs
