Like most programming efforts, the result will leave many possibilities for improvements. The framework, however, should begin to give you an intuition of how to develop your own Smalltalk classes. We've been talking about it for a while, so here it is at last 5.9.2 Playing with Arrays Again. To discuss where a new class might go, it is helpful to have a map of the current classes. The following is the basic class hierarchy of GNU Smalltalk.
Indentation means that the line inherits from the earlier line with one less level of indentation.
While initially a daunting list, you should take the time to hunt down the classes we've examined in this tutorial so far. Notice, for instance, how an Array is a subclass below the SequenceableCollection class. A little puzzling is the relationship of a Bag to a Set, since a Bag is actually a Set supporting multiple occurrences of its elements. The answer lies in the purpose of both a Set and a Bag. That's why Set being a subclass or Bag, or the other way round, would be a source of problems in the actual implementation of the class.