Last-in first-out stacks.
This module implements stacks (LIFOs), with in-place modification.
val create : unit -> 'a tReturn a new stack, initially empty.
val push : 'a -> 'a t -> unitpush x s adds the element x at the top of stack s.
val pop : 'a t -> 'apop s removes and returns the topmost element in stack s, or raises Empty if the stack is empty.
val pop_opt : 'a t -> 'a optionpop_opt s removes and returns the topmost element in stack s, or returns None if the stack is empty.
val top : 'a t -> 'atop s returns the topmost element in stack s, or raises Empty if the stack is empty.
val top_opt : 'a t -> 'a optiontop_opt s returns the topmost element in stack s, or None if the stack is empty.
val clear : 'a t -> unitDiscard all elements from a stack.
val is_empty : 'a t -> boolReturn true if the given stack is empty, false otherwise.
val length : 'a t -> intReturn the number of elements in a stack. Time complexity O(1)
val iter : ('a -> unit) -> 'a t -> unititer 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.
val fold : ('b -> 'a -> 'b) -> 'b -> 'a t -> 'bfold f accu s is (f (... (f (f accu x1) x2) ...) xn) where x1 is the top of the stack, x2 the second element, and xn the bottom element. The stack is unchanged.
Iterate on the stack, top to bottom. It is safe to modify the stack during iteration.
Add the elements from the sequence on the top of the stack.