Import is Not Inheritance Why We Need Both: Modules and Classes

摘要

The design of many popular object-oriented languages like Smalltalk, Eiffel, or Sather follows a certain trend: The class is the only structuring form. In this paper, the need for having modules besides classes is claimed. Modules stem from a different language family and at first glance it seems that they can easily be unified with classes. Among other things, unifying modules and classes carries the danger of unifying the import and inheritance relationships. Constructs in several languages arc discussed that indicate that modules and classes should indeed be kept separate.