The View Matcher is a structured browser for Smalltalk/V. It presents a set of integrated and dynamic views of a running application, intended to coordinate and rationalize a programmer's early understanding of Smalltalk and its environment. We describe the system through two user scenarios involving exploration of the model-view-controller paradigm.Object-oriented programming (OOP) technology has redefmed programming and the psychological implications of programmin g activity in a variety of ways. In this paradigm, programs are communicating objects, and progr amming is using and/or specializing existent objects and their methods. Identifying the right computational objects and their message protocols is the major programming task. Traditionally important programmin g tasks, like designing control flow, are commensurately supplanted.The development of OOP was explicitly motivated by psychological rationales; thinking in terms of communicating objects is supposed to be natural, more natural than designing by functional decomposition [7, 121. It is becoming recognized that there is a distinctive cognitive psychology of object-oriented programming and design [13], but it is clear that this includes distinctive learning challenges [9, 10, 143. For example, OOP entails substantial interactive search and management in vast code libraries, like Smalltalk's Class Hierarchy, to achieve even simple results. This can be a formidable obstacle.Pemrission to copy without fee all or part of thii material is granted provided that the copies are not made or distributed for direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republish requires a fee and/or specific pemkssion. 0 1990 ACM 0-89791~345-O/90/0004-0431 1.50We have become interested in how programmers get started with Smalltalk programming. Our approach has been to deveIop a series of tools to support learning by means of working with concrete examples; we have previously applied this approach to designing instruction for interactive end-user office applications [4, S]. In this paper, we describe one of these tools, the View Matcher.
THE VIEW MATCHERThe View Matcher is a structured browser for Smalltalk/V [SJ. It presents multiple views of an up plication, in contrast to a strictly logical decomposition of programming objects as in the Smalltalk Class I lierarchy Browser. We provided a recipe database and the games tic-tat-toe, blackjack, and gomoku as sample applications. The user can interact with these applications and at the same time browse various aspccts of the running programs, for example, the current stack of methods, the source code and instance variable values for the currently selected method, and of course the application user interface. The user can edit a method and immediately' see the changed code and its effects on application execution.Our target user population is experienced p...
