Dramatically simplify macro def

heliaxdev · Dec 5, 2024 · b9ebedd · b9ebedd
1 parent 5ea554f
commit b9ebedd
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Showing 2 changed files with 26 additions and 77 deletions.
diff --git a/crates/module-macros/src/lib.rs b/crates/module-macros/src/lib.rs
@@ -1,52 +1,29 @@
 extern crate proc_macro;
 
-use quote::{quote, ToTokens};
-
-#[proc_macro_derive(ModuleFromMiddleware)]
-pub fn derive_module_from_middleware(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
-    derive_module_from_middleware_inner(input.into()).into()
+use quote::quote;
+
+/// Generate an IBC module from a type that implements
+/// an IBC middleware module.
+///
+/// ## Example
+///
+/// ```ignore
+/// from_middleware! {
+///     impl<M> Module for Middleware<M>
+///     where
+///         M: Module,
+/// }
+/// ```
+#[proc_macro]
+pub fn from_middleware(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    from_middleware_inner(input.into()).into()
 }
 
-fn derive_module_from_middleware_inner(
-    input: proc_macro2::TokenStream,
+fn from_middleware_inner(
+    impl_def_up_to_block: proc_macro2::TokenStream,
 ) -> proc_macro2::TokenStream {
-    let _struct = syn::parse2::<syn::ItemStruct>(input).expect("Expected struct definition");
-
-    let struct_generics = &_struct.generics;
-    let struct_generics_params = &struct_generics.params;
-
-    let (name, types) = fetch_name_with_generic_params(&_struct);
-    let where_clauses = {
-        let mut clauses =
-            struct_generics
-                .where_clause
-                .clone()
-                .unwrap_or_else(|| syn::WhereClause {
-                    where_token: Default::default(),
-                    predicates: syn::punctuated::Punctuated::new(),
-                });
-
-        for ty in types {
-            clauses
-                .predicates
-                .push(syn::WherePredicate::Type(syn::PredicateType {
-                    lifetimes: None,
-                    bounded_ty: syn::Type::Verbatim(ty),
-                    colon_token: Default::default(),
-                    bounds: {
-                        let mut b = syn::punctuated::Punctuated::new();
-                        b.push(syn::TypeParamBound::Verbatim(quote!(Module)));
-                        b
-                    },
-                }));
-        }
-
-        quote!(#clauses)
-    };
-
     quote! {
-        impl<#struct_generics_params> Module for #name
-        #where_clauses
+        #impl_def_up_to_block
         {
             #[inline(always)]
             fn on_chan_open_init_validate(
@@ -251,35 +228,3 @@ fn derive_module_from_middleware_inner(
         }
     }
 }
-
-fn fetch_name_with_generic_params(
-    _struct: &syn::ItemStruct,
-) -> (proc_macro2::TokenStream, Vec<proc_macro2::TokenStream>) {
-    let mut types = vec![];
-    let mut consts = vec![];
-    let mut lifetimes = vec![];
-
-    for param in _struct.generics.params.iter() {
-        match param {
-            syn::GenericParam::Type(type_) => types.push(type_.ident.to_token_stream()),
-            syn::GenericParam::Lifetime(life_def) => {
-                lifetimes.push(life_def.lifetime.to_token_stream())
-            }
-            syn::GenericParam::Const(constant) => consts.push(constant.ident.to_token_stream()),
-        }
-    }
-
-    let ident = &_struct.ident;
-    let (all_params, types) = {
-        let (mut output, mut consts, types) = (lifetimes, consts, types);
-        output.append(&mut consts);
-        output.extend(types.iter().cloned());
-        (output, types)
-    };
-
-    let name = quote! {
-        #ident < #(#all_params),* >
-    };
-
-    (name, types)
-}
diff --git a/crates/module/src/lib.rs b/crates/module/src/lib.rs
@@ -239,14 +239,18 @@ pub trait MiddlewareModule {
 
 #[cfg(test)]
 mod tests {
-    use ibc_middleware_module_macros::ModuleFromMiddleware;
+    use ibc_middleware_module_macros::from_middleware;
     use ibc_testkit::testapp::ibc::applications::transfer::types::DummyTransferModule;
 
     use super::*;
 
-    #[derive(Debug, ModuleFromMiddleware)]
+    #[derive(Debug)]
     struct DummyMiddleware<M>(M);
 
+    from_middleware! {
+        impl<M: Module> Module for DummyMiddleware<M>
+    }
+
     impl<M> MiddlewareModule for DummyMiddleware<M>
     where
         M: Module,