export interface Stack<T> {
    head: StackItem<T> | undefined;
    length: number;
}
export interface StackItem<T> {
    value: T;
    previous: StackItem<T> | undefined;
}
export declare function createStack<T>(): Stack<T>;
export declare function pushStackItem<T>(value: T, stack: Stack<T>): Stack<T>;
export declare function getStackItems<T>(stack: Stack<T>): Array<T>;