module Core_stack:sig..end
Stack_intf for documentation.
    The implementation will grow the array as necessary, and will never automatically
    shrink the array.  One can use set_capacity to explicitly resize the array.
include Stack_intf.S
val capacity : 'a t -> intcapacity t returns the length of the array backing t.val set_capacity : 'a t -> int -> unitset_capacity t capacity sets the length of the array backing t to max capacity
    (length t).  To shrink as much as possible, do set_capacity t 0.