src/TraitBuilder.ts

@@ -6,34 +6,6 @@ import { Extend, StaticMembers } from "./util"
 
 declare const implSuperSymbol: unique symbol
 
-type ImplSuper<This> = (
-    This extends TraitBuilder<
-        any,
-        infer Abstract,
-        infer StaticAbstract,
-        infer ImplClass
-    >
-        ? (
-            AbstractClass<
-                Simplify<
-                    Extend<[
-                        Abstract,
-                        InstanceType<ImplClass>,
-                    ]>
-                >
-            > &
-
-            Simplify<
-                Extend<[
-                    StaticAbstract,
-                    StaticMembers<ImplClass>,
-                ]>
-            > &
-            { readonly [implSuperSymbol]: true }
-        )
-        : never
-)
-
 
 export class TraitBuilder<
     SuperExpression extends TraitExpression<
@@ -44,6 +16,8 @@ export class TraitBuilder<
     StaticAbstract  extends object,
     ImplClass       extends AbstractClass<object, []>,
 > {
+    declare ["constructor"]: typeof TraitBuilder
+
     constructor(
         readonly traitSuperExpression:  SuperExpression,
         readonly traitAbstract:         Abstract,
@@ -51,10 +25,11 @@ export class TraitBuilder<
         readonly traitApply:            (Super: AbstractClass<object>) => ImplClass,
     ) {}
 
+
     abstract<A extends Abstract>(
         _: (Super: AbstractClass<Abstract>) => AbstractClass<A, []>
     ) {
-        return new TraitBuilder(
+        return new this.constructor(
             this.traitSuperExpression,
             {} as Simplify<A>,
             this.traitStaticAbstract,
@@ -65,7 +40,7 @@ export class TraitBuilder<
     staticAbstract<A extends StaticAbstract>(
         _: (Super: AbstractClass<StaticAbstract>) => AbstractClass<A, []>
     ) {
-        return new TraitBuilder(
+        return new this.constructor(
             this.traitSuperExpression,
             this.traitAbstract,
             {} as Simplify<A>,
@@ -74,11 +49,11 @@ export class TraitBuilder<
     }
 
     implement<
-        ImplClassWithAbstract extends ImplSuper<typeof this>  // TODO: find a way to set the constraint to concrete classes while keeping the Super arg as an abstract class
+        ImplClassWithAbstract extends TraitBuilder.ImplSuper<typeof this>  // TODO: find a way to set the constraint to concrete classes while keeping the Super arg as an abstract class
     >(
-        apply: (Super: ImplSuper<typeof this>) => ImplClassWithAbstract
+        apply: (Super: TraitBuilder.ImplSuper<typeof this>) => ImplClassWithAbstract
     ) {
-        return new TraitBuilder(
+        return new this.constructor(
             this.traitSuperExpression,
             this.traitAbstract,
             this.traitStaticAbstract,
@@ -103,6 +78,7 @@ export class TraitBuilder<
         )
     }
 
+
     build() {
         return new Trait(
             this.traitSuperExpression,
@@ -113,6 +89,37 @@ export class TraitBuilder<
     }
 }
 
+export namespace TraitBuilder {
+    export type ImplSuper<This> = (
+        This extends TraitBuilder<
+            any,
+            infer Abstract,
+            infer StaticAbstract,
+            infer ImplClass
+        >
+            ? (
+                AbstractClass<
+                    Simplify<
+                        Extend<[
+                            Abstract,
+                            InstanceType<ImplClass>,
+                        ]>
+                    >
+                > &
+
+                Simplify<
+                    Extend<[
+                        StaticAbstract,
+                        StaticMembers<ImplClass>,
+                    ]>
+                > &
+                { readonly [implSuperSymbol]: true }
+            )
+            : never
+    )
+}
+
+
 export const trait = new TraitBuilder(
     new TraitExpression(TraitExpression.NullSuperclass, []),
     {} as object,