;+
; NAME: stackpop
;
; PURPOSE:
; 	pops a variable off of a stack. 
; NOTE
; 	If the stack only contains one item
; 	it becomes undefined after the item is popped off.
;
;		see also stackpush.pro
;		
; INPUTS:
; 	stack	an array functioning as a stack
; KEYWORDS:
; OUTPUTS:
; 	returns the last element of the stack, and shortens the stack 
; 	accordingly.
;
; HISTORY:
; 	Began 2002-04-01 00:48:36 by Marshall Perrin 
;-

function stackpop,stack
	checkargnum,n_params(),1,"stackpop,stack"

	n = n_elements(stack)
	if n gt 1 then begin
		var = stack[n-1]

		stack = stack[0:n-2]
		return,var
	endif else begin
		var = stack[0]
		b = temporary(stack)
		return,var
	endelse

end