Files
robinsr/proto/proto-derive/src/lib.rs
T

28 lines
807 B
Rust

use proc_macro::TokenStream;
use quote::{quote, ToTokens};
use syn::{parse_macro_input, DeriveInput, Meta, MetaList};
#[proc_macro_derive(CmdID, attributes(cmdid))]
pub fn message_id_derive(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let struct_name = input.ident;
let id = match input
.attrs
.iter()
.find(|attr| attr.path().is_ident("cmdid"))
{
Some(attr) => match attr.meta {
Meta::List(MetaList { ref tokens, .. }) => tokens.into_token_stream(),
_ => panic!("Invalid cmdid attribute value"),
},
_ => 0u16.into_token_stream(),
};
TokenStream::from(quote! {
impl crate::CmdID for #struct_name {
const CMD_ID: u16 = #id;
}
})
}