RosettaCodeData/Task/Undefined-values/BBC-BASIC/undefined-values-2.basic

      PROCtest
      END

      DEF PROCtest
      LOCAL array()
      IF !^array() < 2 PRINT "Array is undefined"
      DIM array(1,2)
      IF !^array() > 1 PRINT "Array is defined"

      !^array() = 0 : REM Set array to undefined state
      ENDPROC