anchor.diff:  ! Implementation of a simple queue that holds some generic nodes that hold data.
   ! Author: Thomas Lang
   ! Version: 2015-08-25
  -MODULE Gen_Stack
  +MODULE Gen_Queue
     IMPLICIT NONE
   
     PRIVATE
  
positive.code: 
    ! Free the queue
    CALL queue_free(queue)  
  END PROGRAM StackTest
  
negative.code: 
      queue_data = selfcopy%data
    END SUBROUTINE queue_peek
  END MODULE Gen_Queue
  
  ! Main program, testing.
  ! Author: Thomas Lang
  ! Version: 2015-08-27
  PROGRAM QueueTest
    USE Gen_Queue
    USE Node
    IMPLICIT NONE
  
  