Parameterize CompactForm String for optional SCALE impl

src/form.rs

@@ -33,7 +33,7 @@
 use crate::prelude::{
     any::TypeId,
     fmt::Debug,
-    string::String,
+    marker::PhantomData,
 };
 
 use crate::{
@@ -51,7 +51,7 @@ pub trait Form {
     /// The type representing the type.
     type Type: PartialEq + Eq + PartialOrd + Ord + Clone + Debug;
     /// The string type.
-    type String: Serialize + PartialEq + Eq + PartialOrd + Ord + Clone + Debug;
+    type String: PartialEq + Eq + PartialOrd + Ord + Clone + Debug;
 }
 
 /// A meta meta-type.
@@ -76,9 +76,12 @@ impl Form for MetaForm {
 ///
 /// `type String` is owned in order to enable decoding
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Serialize, Debug)]
-pub enum CompactForm {}
+pub struct CompactForm<S = &'static str>(PhantomData<S>);
 
-impl Form for CompactForm {
+impl<S> Form for CompactForm<S>
+where
+    S: PartialEq + Eq + PartialOrd + Ord + Clone + Debug,
+{
     type Type = UntrackedSymbol<TypeId>;
-    type String = String;
+    type String = S;
 }

src/registry.rs

@@ -27,9 +27,9 @@
 use crate::prelude::{
     any::TypeId,
     collections::BTreeMap,
+    fmt::Debug,
     mem,
     num::NonZeroU32,
-    string::ToString,
     vec::Vec,
 };
 
@@ -50,6 +50,7 @@ use scale::{
     Encode,
 };
 use serde::{
+    de::DeserializeOwned,
     Deserialize,
     Serialize,
 };
@@ -67,7 +68,7 @@ impl IntoCompact for &'static str {
     type Output = <CompactForm as Form>::String;
 
     fn into_compact(self, _registry: &mut Registry) -> Self::Output {
-        self.to_string()
+        self
     }
 }
 
@@ -201,8 +202,12 @@ impl Registry {
 
 /// A read-only registry, to be used for decoding/deserializing
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize, Decode)]
-pub struct RegistryReadOnly {
-    types: Vec<Type<CompactForm>>,
+#[serde(bound(serialize = "S: Serialize", deserialize = "S: DeserializeOwned",))]
+pub struct RegistryReadOnly<S = &'static str>
+where
+    S: PartialEq + Eq + PartialOrd + Ord + Clone + Debug,
+{
+    types: Vec<Type<CompactForm<S>>>,
 }
 
 impl From<Registry> for RegistryReadOnly {
@@ -213,14 +218,17 @@ impl From<Registry> for RegistryReadOnly {
     }
 }
 
-impl RegistryReadOnly {
+impl<S> RegistryReadOnly<S>
+where
+    S: PartialEq + Eq + PartialOrd + Ord + Clone + Debug,
+{
     /// Returns the type definition for the given identifier, `None` if no type found for that ID.
-    pub fn resolve(&self, id: NonZeroU32) -> Option<&Type<CompactForm>> {
+    pub fn resolve(&self, id: NonZeroU32) -> Option<&Type<CompactForm<S>>> {
         self.types.get((id.get() - 1) as usize)
     }
 
     /// Returns an iterator for all types paired with their associated NonZeroU32 identifier.
-    pub fn enumerate(&self) -> impl Iterator<Item = (NonZeroU32, &Type<CompactForm>)> {
+    pub fn enumerate(&self) -> impl Iterator<Item = (NonZeroU32, &Type<CompactForm<S>>)> {
         self.types.iter().enumerate().map(|(i, ty)| {
             let id = NonZeroU32::new(i as u32 + 1).expect("i + 1 > 0; qed");
             (id, ty)

test_suite/tests/codec.rs

@@ -28,6 +28,7 @@ use scale_info::{
     form::CompactForm,
     prelude::{
         num::NonZeroU32,
+        string::String,
         vec,
         vec::Vec,
     },
@@ -60,7 +61,7 @@ fn scale_encode_then_decode_to_readonly() {
     let mut encoded = registry.encode();
     let original_serialized = serde_json::to_value(registry).unwrap();
 
-    let readonly_decoded = RegistryReadOnly::decode(&mut &encoded[..]).unwrap();
+    let readonly_decoded = RegistryReadOnly::<String>::decode(&mut &encoded[..]).unwrap();
     assert!(readonly_decoded
         .resolve(NonZeroU32::new(1).unwrap())
         .is_some());
@@ -76,7 +77,7 @@ fn json_serialize_then_deserialize_to_readonly() {
 
     let original_serialized = serde_json::to_value(registry).unwrap();
     // assert_eq!(original_serialized, serde_json::Value::Null);
-    let readonly_deserialized: RegistryReadOnly =
+    let readonly_deserialized: RegistryReadOnly<String> =
         serde_json::from_value(original_serialized.clone()).unwrap();
     assert!(readonly_deserialized
         .resolve(NonZeroU32::new(1).unwrap())