export declare function iter<T>(x: Iterable<T>): BetterIterable<T>;
export declare class BetterIterable<T> {
    readonly values: Iterable<T>;
    constructor(values: Iterable<T>);
    map<U>(f: (_: T) => U): BetterIterable<U>;
    flatMap<U>(f: (_: T) => Iterable<U>): BetterIterable<U>;
    zip<U>(gen: Generator<U>): BetterIterable<[T, U]>;
    every(f: (_: T) => boolean): boolean;
    to_array(): T[];
}