export function todo<T>(msg?: string): T {
    class NotImplemented extends Error {}
    throw new NotImplemented(msg);
}

export function exhausted(_: never) {
    class Unexhausted extends Error {}
    throw new Unexhausted();
}

export type Res<V, E> = Ok<V> | Err<E>;
export type Ok<V> = { ok: true; val: V };
export type Err<E> = { ok: false; val: E };

export const Ok = <V>(val: V): Ok<V> => ({ ok: true, val });
export const Err = <E>(val: E): Err<E> => ({ ok: false, val });

export const Res = { Ok, Err } as const;

export type ControlFlow<
    R = undefined,
    V = undefined,
> = Break<R> | Continue<V>;

export type Break<R> = { break: true; val: R };
export type Continue<V> = { break: false; val: V };

export const ControlFlow = {
    Break: <R>(val: R): Break<R> => ({ break: true, val }),
    Continue: <V>(val: V): Continue<V> => ({ break: false, val }),
} as const;

export const range = (length: number) => (new Array(length).fill(0));