# Module Stack

    module Stack: sig  end

Last-in first-out stacks.

This module implements stacks (LIFOs), with in-place modification.

`type `'a` t`
The type of stacks containing elements of type `'a`.

    exception Empty

Raised when `Stack.pop` or `Stack.top` is applied to an empty stack.

    val create : unit -> 'a t

Return a new stack, initially empty.

    val push : 'a -> 'a t -> unit

`push x s` adds the element `x` at the top of stack `s`.

    val pop : 'a t -> 'a

`pop s` removes and returns the topmost element in stack `s`, or raises `Empty` if the stack is empty.

    val top : 'a t -> 'a

`top s` returns the topmost element in stack `s`, or raises `Empty` if the stack is empty.

    val clear : 'a t -> unit

Discard all elements from a stack.

    val copy : 'a t -> 'a t

Return a copy of the given stack.

    val is_empty : 'a t -> bool

Return `true` if the given stack is empty, `false` otherwise.

    val length : 'a t -> int

Return the number of elements in a stack.

    val iter : ('a -> unit) -> 'a t -> unit

`iter f s` applies `f` in turn to all elements of `s`, from the element at the top of the stack to the element at the bottom of the stack. The stack itself is unchanged.