Module Stack


structure Stack = struct ... 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 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.