export declare const executeTco: <T>(v: TcoLike<T>) => T;
export declare class Tco<T> {
    func: TcoFunc<T>;
    constructor(func: TcoFunc<T>);
    execute(): T;
    then<U>(func: (val: T) => TcoLike<U>): TcoThen<T, U>;
}
export declare class TcoThen<T, U> {
    from: TcoLike<T>;
    func: (val: T) => TcoLike<U>;
    constructor(from: TcoLike<T>, func: (val: T) => TcoLike<U>);
    execute(): U;
    then<V>(func: (val: U) => TcoLike<V>): TcoThen<U, V>;
}
export declare type TcoLike<T> = T | Tco<T> | TcoThen<any, T>;
export declare type TcoFunc<T> = () => TcoLike<T>;
export declare const tco: <T extends unknown>(f: TcoFunc<T>) => Tco<T>;