strum_macros/macros/
enum_properties.rs

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1use proc_macro2::TokenStream;
2use quote::quote;
3use syn::{Data, DeriveInput, Fields};
4
5use crate::helpers::{non_enum_error, HasStrumVariantProperties, HasTypeProperties};
6
7pub fn enum_properties_inner(ast: &DeriveInput) -> syn::Result<TokenStream> {
8    let name = &ast.ident;
9    let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
10    let variants = match &ast.data {
11        Data::Enum(v) => &v.variants,
12        _ => return Err(non_enum_error()),
13    };
14    let type_properties = ast.get_type_properties()?;
15    let strum_module_path = type_properties.crate_module_path();
16
17    let mut arms = Vec::new();
18    for variant in variants {
19        let ident = &variant.ident;
20        let variant_properties = variant.get_variant_properties()?;
21        let mut string_arms = Vec::new();
22        // But you can disable the messages.
23        if variant_properties.disabled.is_some() {
24            continue;
25        }
26
27        let params = match variant.fields {
28            Fields::Unit => quote! {},
29            Fields::Unnamed(..) => quote! { (..) },
30            Fields::Named(..) => quote! { {..} },
31        };
32
33        for (key, value) in variant_properties.string_props {
34            string_arms.push(quote! { #key => ::core::option::Option::Some( #value )});
35        }
36
37        string_arms.push(quote! { _ => ::core::option::Option::None });
38
39        arms.push(quote! {
40            &#name::#ident #params => {
41                match prop {
42                    #(#string_arms),*
43                }
44            }
45        });
46    }
47
48    if arms.len() < variants.len() {
49        arms.push(quote! { _ => ::core::option::Option::None });
50    }
51
52    Ok(quote! {
53        impl #impl_generics #strum_module_path::EnumProperty for #name #ty_generics #where_clause {
54            fn get_str(&self, prop: &str) -> ::core::option::Option<&'static str> {
55                match self {
56                    #(#arms),*
57                }
58            }
59        }
60    })
61}
strum_macros/macros/enum_properties.rs

strum_macros/macros/
enum_properties.rs
