strum_macros/macros/
enum_variant_array.rs

1use proc_macro2::TokenStream;
2use quote::quote;
3use syn::{Data, DeriveInput, Fields};
4
5use crate::helpers::{non_enum_error, non_unit_variant_error, HasTypeProperties};
6
7pub fn static_variants_array_inner(ast: &DeriveInput) -> syn::Result<TokenStream> {
8    let name = &ast.ident;
9    let gen = &ast.generics;
10    let (impl_generics, ty_generics, where_clause) = gen.split_for_impl();
11
12    let variants = match &ast.data {
13        Data::Enum(v) => &v.variants,
14        _ => return Err(non_enum_error()),
15    };
16
17    let type_properties = ast.get_type_properties()?;
18    let strum_module_path = type_properties.crate_module_path();
19
20    let idents = variants
21        .iter()
22        .cloned()
23        .map(|v| match v.fields {
24            Fields::Unit => Ok(v.ident),
25            _ => Err(non_unit_variant_error()),
26        })
27        .collect::<syn::Result<Vec<_>>>()?;
28
29    Ok(quote! {
30        impl #impl_generics #strum_module_path::VariantArray for #name #ty_generics #where_clause {
31            const VARIANTS: &'static [Self] = &[ #(#name::#idents),* ];
32        }
33    })
34}
strum_macros/macros/enum_variant_array.rs

strum_macros/macros/
enum_variant_array.rs
