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