Improving the Smalltalk Browser: a case study in Smalltalk development

Abstract

With the advancements being made in computers today, object oriented language environments are fast becoming a reality for more and more people. One of the more widely accepted and used object oriented environments is Smalltalk. This system was used along with C and Ada for a study of possible ways to introduce students to object oriented programming. After developing several implementations in Smalltalk, its advantages become quite clear. However the point here is not to discuss the advantages of Smalltalk, but to talk about some areas of improvement, which were discovered while using the system. However as with any new system there are always areas for improvement, and that is what we wish to discuss here. There are many areas for improvement, but the area of our chief concern is the Browser, or the Class Hierarchy Browser. As a result of other research I was inspired to attempt to improve the Browser, and at least point out its deficiency. Since the main goal of the research was introduction to object oriented programming, this paper discussing the development of the new Browser will serve not only as documentation but also as an example of implementations in Smalltalk. The first part discusses some of the observations and deficiencies that were observed when using the Smalltalk system. Later sections document and discuss the improvements that were implemented. This paper assumes that the reader has seen some Smalltalk previously; however, if the reader has not seen any Smalltalk, many of the general concepts will be accessible. Two points are important: first, Smalltalk is written almost entirely in Smalltalk.; second, any "programs" or code which aré written using Smalltalk modify the system itself. Therefore, no two systems are the same, except when they are first installed. If this seems difficult, consider some more common languages such as C and Pascal. These systems compile the program or code. Then die source code and the object code are set aside, separate from the language or compiler. But in Smalltalk everything you do is part of the system. So if you write a new "program" it becomes part of the system, that is its “code” is available to any other elements of the system.