50 lines
1.5 KiB
Rust

use core::panic;
use proc_macro::TokenStream;
use quote::{quote, quote_spanned};
use syn::{spanned::Spanned, DeriveInput};
#[proc_macro_derive(PushPopParse)]
pub fn pushpop_derive_macro(item: TokenStream) -> TokenStream {
let ast: DeriveInput = syn::parse(item).unwrap();
let struct_ident = ast.ident;
let struct_data: syn::DataStruct = match ast.data {
syn::Data::Struct(struct_data) => struct_data,
syn::Data::Enum(_) => panic!("Error: Enum support not implemented"),
syn::Data::Union(_) => panic!("Error: Union support not implemented"),
};
let recursive = struct_data.fields.iter().map(|f| {
let name = &f.ident;
let ty = &f.ty;
quote_spanned!(f.span()=> let #name = <#ty>::pop_ne_from(&mut source)?;)
});
let names = struct_data.fields.iter().map(|f| {
let name = &f.ident;
quote_spanned!(f.span()=> #name)
});
let pop = struct_data.fields.iter().map(|f| {
let name = &f.ident;
quote_spanned!(f.span()=> PopFromNE::push_ne_into(&self.#name, dest)?;)
});
quote!(
impl PopFromNE for #struct_ident {
fn pop_ne_from(mut source: &mut &[u8]) -> anyhow::Result<Self>
where
Self: Sized,
{
#(#recursive)*
Ok(#struct_ident{
#(#names),*
})
}
fn push_ne_into<T: Pushable>(&self, dest: &mut T) -> anyhow::Result<()> {
#(#pop)*
Ok(())
}
})
.into()
}