export declare class Cons<A> {
    value: A;
    next: Cons<A> | undefined;
    constructor(value: A, next: Cons<A> | undefined);
    toArray(): A[];
    nth(index: number): A | undefined;
}
export declare function copyFirst<A>(n: number, list: Cons<A>): Cons<A>;
export declare function concat<A>(a: Cons<A>, b: Cons<A>): Cons<A>;