Module Stack: last-in first-out stacks
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This module implements stacks (LIFOs), with in-place modification.
type 'a t
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The type of stacks containing elements of type 'a.
exception Empty
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Raised when pop is applied to an empty stack.
val create: unit -> 'a t
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Return a new stack, initially empty.
val push: 'a -> 'a t -> unit
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push x s adds the element x at the top of stack s.
val pop: 'a t -> 'a
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pop s removes and returns the topmost element in stack s,
or raises Empty if the stack is empty.
val clear : 'a t -> unit
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Discard all elements from a stack.
val length: 'a t -> int
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Return the number of elements in a stack.
val iter: ('a -> 'b) -> 'a t -> unit
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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.