Modules: Switch Module Closures to be AsyncGenerators

README.md

@@ -130,6 +130,8 @@ Thus, evaluators are responsible for providing functions to allow modules to rea
 Each of the data types passed as identifier have functions to create an instance of that data type,
 as well as read and write data to it (or call it, in the case of closures). See `conductor/types/IDataHandler`.
 
+In the case of closures, the `closure_call` and `closure_call_unchecked` return `AsyncGenerator`s. In the case of CSE machines, yielding a closure call to a CSE closure would allow the module function to defer the execution until the closure's return value is executed.
+
 ### Standard library
 
 A standard library of functions must be made available to modules. See `conductor/stdlib` for sample implementations.

src/conductor/stdlib/list/accumulate.ts

@@ -11,12 +11,11 @@ import { DataType, type IDataHandler, type TypedValue } from "../../types"
  * @param resultType The (expected) type of the result.
  * @returns A Promise resolving to the result of accumulating the Closure over the List.
  */
-export async function accumulate<T extends Exclude<DataType, DataType.VOID>>(this: IDataHandler, op: TypedValue<DataType.CLOSURE, T>, initial: TypedValue<T>, sequence: TypedValue<DataType.LIST>, resultType: T): Promise<TypedValue<T>> {
+export async function* accumulate<T extends Exclude<DataType, DataType.VOID>>(this: IDataHandler, op: TypedValue<DataType.CLOSURE, T>, initial: TypedValue<T>, sequence: TypedValue<DataType.LIST>, resultType: T): AsyncGenerator<void, TypedValue<T>, undefined> {
     const vec = await this.list_to_vec(sequence);
     let result = initial;
     for (let i = vec.length - 1; i >= 0; --i) {
-        result = await this.closure_call(op, [vec[i], result], resultType);
+        result = yield* this.closure_call(op, [vec[i], result], resultType);
     }
-
     return result;
 }

src/conductor/types/moduleInterface/ExternCallable.ts

@@ -5,4 +5,4 @@ type DataTypeMap<T extends readonly [...DataType[]]> = {
     [Idx in keyof T]: TypedValue<T[Idx]>
 };
 
-export type ExternCallable<Arg extends readonly DataType[], Ret extends DataType> = (...args: DataTypeMap<Arg>) => TypedValue<Ret> | Promise<TypedValue<Ret>>;
+export type ExternCallable<Arg extends readonly DataType[], Ret extends DataType> = (...args: DataTypeMap<Arg>) => AsyncGenerator<void, TypedValue<Ret>, undefined>;

src/conductor/types/moduleInterface/IDataHandler.ts

@@ -145,15 +145,15 @@ export interface IDataHandler {
      * @param returnType The expected type of the returned value.
      * @returns A promise to the returned typed value.
      */
-    closure_call<T extends DataType>(c: TypedValue<DataType.CLOSURE, T>, args: TypedValue<DataType>[], returnType: T): Promise<TypedValue<NoInfer<T>>>;
+    closure_call<T extends DataType>(c: TypedValue<DataType.CLOSURE, T>, args: TypedValue<DataType>[], returnType: T): AsyncGenerator<void, TypedValue<NoInfer<T>>, undefined>;
 
     /**
      * Calls a Closure of known return type.
      * @param c The Closure to be called.
      * @param args An array of typed arguments to be passed to the Closure.
      * @returns A promise to the returned typed value.
      */
-    closure_call_unchecked<T extends DataType>(c: TypedValue<DataType.CLOSURE, T>, args: TypedValue<DataType>[]): Promise<TypedValue<NoInfer<T>>>;
+    closure_call_unchecked<T extends DataType>(c: TypedValue<DataType.CLOSURE, T>, args: TypedValue<DataType>[]): AsyncGenerator<void, TypedValue<NoInfer<T>>, undefined>;
 
     /**
      * Asserts the arity of a Closure.
@@ -208,6 +208,6 @@ export interface IDataHandler {
     list(...elements: TypedValue<DataType>[]): Promise<TypedValue<DataType.LIST>>;
     is_list(xs: TypedValue<DataType.LIST>): Promise<boolean>;
     list_to_vec(xs: TypedValue<DataType.LIST>): Promise<TypedValue<DataType>[]>;
-    accumulate<T extends Exclude<DataType, DataType.VOID>>(op: TypedValue<DataType.CLOSURE, T>, initial: TypedValue<T>, sequence: TypedValue<DataType.LIST>, resultType: T): Promise<TypedValue<T>>;
+    accumulate<T extends Exclude<DataType, DataType.VOID>>(op: TypedValue<DataType.CLOSURE, T>, initial: TypedValue<T>, sequence: TypedValue<DataType.LIST>, resultType: T): AsyncGenerator<void, TypedValue<T>, undefined>;
     length(xs: TypedValue<DataType.LIST>): Promise<number>;
 }