sui_field_count_derive/
lib.rs

1// Copyright (c) Mysten Labs, Inc.
2// SPDX-License-Identifier: Apache-2.0
3use proc_macro::TokenStream;
4use quote::quote;
5use syn::{DeriveInput, parse_macro_input};
6
7#[proc_macro_derive(FieldCount)]
8pub fn field_count_derive(input: TokenStream) -> TokenStream {
9    let input = parse_macro_input!(input as DeriveInput);
10    let name = input.ident;
11    let generics = input.generics;
12    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
13
14    let fields_count = match input.data {
15        syn::Data::Struct(data_struct) => data_struct.fields.len(),
16        syn::Data::Enum(data_enum) => data_enum.variants.len(),
17        syn::Data::Union(_) => panic!("FieldCount cannot be derived for unions"),
18    };
19
20    let expanded = quote! {
21        impl #impl_generics FieldCount for #name #ty_generics #where_clause {
22            const FIELD_COUNT: usize = #fields_count;
23        }
24    };
25    TokenStream::from(expanded)
26}
sui_field_count_derive/lib.rs

sui_field_count_derive/
lib.rs
