function defined,var

;+
;
; Result = DEFINED(VAR)
;
; Function returns integer 1 if VAR is exists, 0 if VAR is undefined.
; Uses size(var,/type) to determine whether VAR is undefined.
;
; Katie Peek / June 2006
; 
;+

if (size(var,/type) eq 0) then def=0 else def=1

return,def
end