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use syn::{Data, DataStruct, DeriveInput, export::TokenStream, Fields};
use quote::quote;
#[proc_macro_derive(Entity)]
pub fn entity_derive(input: TokenStream) -> TokenStream {
let ast: DeriveInput = syn::parse(input).unwrap();
if let Data::Struct(DataStruct { fields: Fields::Named(ref fields), .. }) = &ast.data {
if fields.named.iter().any(|field| {
match field.ident {
Some(ref ident) => ident.to_string() == "id",
None => false
}
}) {
impl_entity(&ast)
} else {
panic!("Entity derive must be used on a struct a field named \"id\".")
}
} else {
panic!("Entity derive must be used on a struct with named fields.")
}
}
fn impl_entity(ast: &syn::DeriveInput) -> TokenStream {
let name = &ast.ident;
let expanded = quote! {
impl dodo::Entity for #name {
fn id(&self) -> Option<uuid::Uuid> { self.id }
fn set_id(&mut self, id: Option<uuid::Uuid>) { self.id = id }
}
};
TokenStream::from(expanded)
}