Meta-type-system

Cargo.toml

@@ -65,3 +65,10 @@ tracing = { version = "0.1.40", default-features = false }
 clap = { version = "4.5.4", features = ["derive"] }
 env_logger = { version = "0.11.3" }
 tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
+
+
+# proc macros
+syn = { version = "2", features = ["full", "extra-traits"] }
+quote = "1"
+proc-macro2 = "1"
+proc-macro-crate = "3"

Makefile

@@ -42,6 +42,9 @@ clippy:
 	SKIP_WASM_BUILD= cargo clippy -- -D warnings
 	cd poc/guests; cargo clippy
 
+test:
+	SKIP_WASM_BUILD= cargo test
+
 chainspec:
 	cargo build -p poc-runtime --release
 	mkdir -p output

xcq-extension/procedural/Cargo.toml

@@ -10,7 +10,7 @@ version.workspace = true
 proc-macro = true
 
 [dependencies]
-syn = { version = "2", features = ["full", "extra-traits"] }
-quote = "1"
-proc-macro2 = "1"
+quote = { workspace = true }
+syn = { workspace = true }
+proc-macro2 = { workspace = true }
 twox-hash = "1.6.3"

xcq-types/Cargo.toml

@@ -8,7 +8,16 @@ repository.workspace = true
 version.workspace = true
 
 [dependencies]
+cfg-if = "1.0"
+codec = { package = "parity-scale-codec", version = "3", default-features = false, features = [
+    "derive",
+] }
+serde = { version = "1", default-features = false, optional = true, features = [
+    "derive",
+] }
+fortuples = "0.9"
+xcq-types-derive = { path = "derive" }
 
 [features]
 default = ["std"]
-std = []
+std = ["codec/std"]

xcq-types/derive/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "xcq-types-derive"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+quote = { workspace = true }
+syn = { workspace = true }
+proc-macro2 = { workspace = true }
+proc-macro-crate = { workspace = true }

xcq-types/derive/src/lib.rs

@@ -0,0 +1,144 @@
+use proc_macro::TokenStream;
+use proc_macro2::TokenStream as TokenStream2;
+use proc_macro_crate::{crate_name, FoundCrate};
+use quote::quote;
+use syn::{punctuated::Punctuated, token::Comma, Data, DataEnum, DataStruct, DeriveInput, Field, Fields};
+
+#[proc_macro_derive(XcqTypeInfo)]
+pub fn derive_xcq_type_info(input: TokenStream) -> TokenStream {
+    match generate(input.into()) {
+        Ok(output) => output.into(),
+        Err(err) => err.to_compile_error().into(),
+    }
+}
+
+fn generate(input: TokenStream2) -> syn::Result<TokenStream2> {
+    let type_info_impl: XcqTypeInfoImpl = XcqTypeInfoImpl::parse(input)?;
+    let type_info_impl_toks = type_info_impl.expand()?;
+    Ok(quote! {
+        // A rust pattern to ensure that the type info is implemented.
+        #[allow(non_upper_case_globals, unused_attributes, unused_imports)]
+        const _: () = {
+            #type_info_impl_toks
+        };
+    })
+}
+
+struct XcqTypeInfoImpl {
+    ast: DeriveInput,
+}
+
+impl XcqTypeInfoImpl {
+    fn parse(input: TokenStream2) -> syn::Result<Self> {
+        let ast = syn::parse2::<DeriveInput>(input)?;
+        // Assume no attributes
+        if !ast.attrs.is_empty() {
+            return Err(syn::Error::new_spanned(ast, "unexpected attributes"));
+        }
+        Ok(Self { ast })
+    }
+
+    fn expand(&self) -> syn::Result<TokenStream2> {
+        let xcq_types = import_xcq_types();
+        let ident = &self.ast.ident;
+
+        // Assume no generics
+        if self.ast.generics.type_params().next().is_some() {
+            return Err(syn::Error::new_spanned(
+                &self.ast.generics,
+                "generics are not supported",
+            ));
+        }
+
+        let type_info = match &self.ast.data {
+            Data::Struct(ref s) => self.generate_struct_type(s),
+            Data::Enum(ref e) => self.generate_enum_type(e),
+            Data::Union(_) => {
+                return Err(syn::Error::new_spanned(&self.ast, "unions are not supported"));
+            }
+        };
+
+        // TODO: No token replacement supported yet
+        Ok(quote! {
+            impl #xcq_types::XcqTypeInfo for #ident {
+                type Identity = Self;
+                fn type_info() -> #xcq_types::XcqType {
+                    #type_info
+                }
+            }
+        })
+    }
+
+    fn generate_struct_type(&self, data_struct: &DataStruct) -> TokenStream2 {
+        let xcq_types = import_xcq_types();
+        let ident = &self.ast.ident;
+        let fields = match data_struct.fields {
+            Fields::Named(ref fields) => self.generate_fields(&fields.named),
+            Fields::Unnamed(ref fields) => self.generate_fields(&fields.unnamed),
+            Fields::Unit => return quote! {},
+        };
+
+        quote! {
+            #xcq_types::StructType {
+                ident: stringify!(#ident).as_bytes().to_vec(),
+                fields: vec![#(#fields),*],
+            }.into()
+        }
+    }
+
+    fn generate_enum_type(&self, data_enum: &DataEnum) -> TokenStream2 {
+        let xcq_types = import_xcq_types();
+        let ident = &self.ast.ident;
+        let variants = data_enum.variants.iter().map(|variant| {
+            let ident = &variant.ident;
+            let fields = match variant.fields {
+                Fields::Named(ref fields) => self.generate_fields(&fields.named),
+                Fields::Unnamed(ref fields) => self.generate_fields(&fields.unnamed),
+                Fields::Unit => return quote! {},
+            };
+            quote! {
+                #xcq_types::Variant {
+                    ident: stringify!(#ident).as_bytes().to_vec(),
+                    fields: vec![#(#fields),*],
+                }
+            }
+        });
+        quote! {
+            #xcq_types::EnumType {
+                ident: stringify!(#ident).as_bytes().to_vec(),
+                variants: vec![#(#variants),*],
+            }.into()
+        }
+    }
+
+    fn generate_fields(&self, fields: &Punctuated<Field, Comma>) -> Vec<TokenStream2> {
+        let xcq_types = import_xcq_types();
+        fields
+            .iter()
+            .map(|f| {
+                let ty = &f.ty;
+                let ident_toks = match &f.ident {
+                    Some(ident) => quote! { stringify!(#ident).as_bytes().to_vec()},
+                    None => quote! { vec![] },
+                };
+                quote! {
+                    #xcq_types::Field {
+                        ident: #ident_toks,
+                        ty: <#ty as #xcq_types::XcqTypeInfo>::type_info(),
+                    }
+                }
+            })
+            .collect()
+    }
+}
+
+fn import_xcq_types() -> TokenStream2 {
+    let found_crate = crate_name("xcq-types").expect("xcq-types not found in Cargo.toml");
+    match found_crate {
+        FoundCrate::Itself => quote! { crate },
+        FoundCrate::Name(name) => {
+            let name = syn::Ident::new(&name, proc_macro2::Span::call_site());
+            quote! { ::#name }
+        }
+    }
+}