derive_more/
mul_like.rs

1use crate::add_like;
2use crate::mul_helpers::generics_and_exprs;
3use crate::utils::{AttrParams, MultiFieldData, RefType, State};
4use proc_macro2::{Span, TokenStream};
5use quote::quote;
6use std::collections::HashSet;
7use std::iter;
8use syn::{DeriveInput, Ident, Result};
9
10pub fn expand(input: &DeriveInput, trait_name: &'static str) -> Result<TokenStream> {
11    let mut state = State::with_attr_params(
12        input,
13        trait_name,
14        quote!(::core::ops),
15        trait_name.to_lowercase(),
16        AttrParams::struct_(vec!["forward"]),
17    )?;
18    if state.default_info.forward {
19        return Ok(add_like::expand(input, trait_name));
20    }
21
22    let scalar_ident = &Ident::new("__RhsT", Span::call_site());
23    state.add_trait_path_type_param(quote!(#scalar_ident));
24    let multi_field_data = state.enabled_fields_data();
25    let MultiFieldData {
26        input_type,
27        field_types,
28        ty_generics,
29        trait_path,
30        trait_path_with_params,
31        method_ident,
32        ..
33    } = multi_field_data.clone();
34
35    let tys = field_types.iter().collect::<HashSet<_>>();
36    let tys = tys.iter();
37    let scalar_iter = iter::repeat(scalar_ident);
38    let trait_path_iter = iter::repeat(trait_path);
39
40    let type_where_clauses = quote! {
41        where #(#tys: #trait_path_iter<#scalar_iter, Output=#tys>),*
42    };
43
44    let (generics, initializers) = generics_and_exprs(
45        multi_field_data.clone(),
46        scalar_ident,
47        type_where_clauses,
48        RefType::No,
49    );
50    let body = multi_field_data.initializer(&initializers);
51    let (impl_generics, _, where_clause) = generics.split_for_impl();
52    Ok(quote!(
53        impl#impl_generics  #trait_path_with_params for #input_type#ty_generics #where_clause {
54            type Output = #input_type#ty_generics;
55            #[inline]
56            fn #method_ident(self, rhs: #scalar_ident) -> #input_type#ty_generics {
57                #body
58            }
59        }
60
61    ))
62}
derive_more/mul_like.rs

derive_more/
mul_like.rs
