fields-converter-derive 0.1.4

Fields-wise type conversions derive macros
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32

use quote::ToTokens;
use struct_data::{Field, StructData};
use syn;

pub fn clone_fields(struct_data: &StructData, to_ty: &syn::Path) -> impl ToTokens {
    let from_ty = &struct_data.name;
    let fields = &struct_data.field_idents;
    let (impl_generics, ty_generics, where_clause) = struct_data.generics.split_for_impl();
    let direct_clones = fields
        .iter()
        .map(|Field { id, .. }| quote!( #id: CloneInto::clone_into(&self.#id) ));
    let reverse_clones = fields
        .iter()
        .map(|Field { id, .. }| quote!( #id: CloneFrom::clone_from(&other.#id) ));
    quote!(
        impl #impl_generics CloneInto<#to_ty #ty_generics> for #from_ty #ty_generics #where_clause {
            fn clone_into(&self) -> #to_ty #ty_generics {
                #to_ty {
                    #( #direct_clones ),*
                }
            }
        }

        impl #impl_generics CloneFrom<#to_ty #ty_generics> for #from_ty #ty_generics #where_clause {
            fn clone_from(other: &#to_ty #ty_generics) -> Self {
                #from_ty {
                    #( #reverse_clones ),*
                }
            }
        }
    )
}