export interface ExtensibleFunction<P extends any[], R=any> {
    new (func: (...args: P) => R): ((...args: P) => R) & this
    (...args: P): R;
}

export class ExtensibleFunction<P, R> {
    constructor(f: (...args: P) => R) {
        return Object.setPrototypeOf(f, this.constructor.prototype);
    }
}