Working trait expression implements

src/util/extend.ts

@@ -0,0 +1,16 @@
+import { Call, Fn, Tuples } from "hotscript"
+
+
+type CommonKeys<A, B> = Extract<keyof A, keyof B>
+
+type ExtendReducer<Super, Self> = (
+    Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
+        ? Omit<Super, CommonKeys<Self, Super>> & Self
+        : never
+)
+interface ExtendReducerFn extends Fn {
+    return: ExtendReducer<this["arg0"], this["arg1"]>
+}
+
+export type ExtendFn = Tuples.Reduce<ExtendReducerFn, {}>
+export type Extend<T extends readonly object[]> = Call<ExtendFn, T>

src/util/index.ts

@@ -1,3 +1,3 @@
 export * from "./class"
+export * from "./extend"
 export * from "./inheritance"
-export * from "./trait"

src/util/trait.ts

@@ -1,22 +0,0 @@
-import { Trait, TraitAbstractMembers, TraitClass } from ".."
-
-
-export type TraitsAbstractMembers<Traits extends readonly Trait<any, any>[]> = (
-    Traits extends [infer T, ...infer Rest]
-        ? T extends Trait<any, any>
-            ? Rest extends Trait<any, any>[]
-                ? [TraitAbstractMembers<T>, ...TraitsClasses<Rest>]
-                : never
-            : never
-        : []
-)
-
-export type TraitsClasses<Traits extends readonly Trait<any, any>[]> = (
-    Traits extends [infer T, ...infer Rest]
-        ? T extends Trait<any, any>
-            ? Rest extends Trait<any, any>[]
-                ? [TraitClass<T>, ...TraitsClasses<Rest>]
-                : never
-            : never
-        : []
-)