fn duplicate_variant()

in gazebo_derive/src/util.rs [60:107]

• 45 lines of code
• 1 McCabe index (conditional complexity)

fn duplicate_variant(data: &Variant, duplicate: &TokenStream) -> TokenStream {
    let ctor = &data.ident;
    match data.fields {
        Fields::Named(ref fields) => {
            // Self::Ctor{x,y} => {x: clone(x), y: clone(y)}
            let (pats, es): (Vec<_>, Vec<_>) = fields
                .named
                .iter()
                .map(|f| {
                    let name = &f.ident;
                    (
                        quote_spanned! {f.span() =>
                            #name
                        },
                        quote_spanned! {f.span() =>
                            #name: #duplicate(#name)
                        },
                    )
                })
                .unzip();
            quote! {
                Self::#ctor{ #(#pats, )* } => Self::#ctor{ #(#es, )* }
            }
        }
        Fields::Unnamed(ref fields) => {
            // Self::Ctor(v0,v1) => Self::Ctor(clone(v0), clone(v1))
            let (pats, es): (Vec<_>, Vec<_>) = fields
                .unnamed
                .iter()
                .enumerate()
                .map(|(i, f)| {
                    let var = Ident::new(&format!("v{}", i), f.span());
                    (
                        quote_spanned! {f.span() => #var},
                        quote_spanned! {f.span() => #duplicate(#var)},
                    )
                })
                .unzip();
            quote! {
                Self::#ctor( #(#pats,)* ) => Self::#ctor( #(#es,)* )
            }
        }
        Fields::Unit => {
            // Self::Ctor => Self::Ctor
            quote!(Self::#ctor => Self::#ctor)
        }
    }
}