Toward visual debugging

Much of the recent research in software visualization has been polarized toward two opposite domains. In one domain that we call data structure and program visualization , low-level canonical views of program structures are generated automatically. These types of views, which do not require programmer input or intervention, can be useful for testing and debugging software. Often, however, their generic, low-level views are not expressive enough to convey adequately how a program functions. In the second domain called algorithm animation , designers handcraft abstract, application-specific views that are useful for program understanding and teaching. Unfortunately, since algorithm animation development typically requires time-consuming design with a graphics package, it will not be used for debugging, where timeliness is a necessity. However, we speculate that the application-specific nature of algorithm animation views could be a valuable debugging aid for software developers as well, if only the views could be easy and rapid to create. We have developed a system called Lens that occupies a unique niche between the two domains discussed above and explores the capabilities that such a system may offer. Lens allows programmers to build rapidly (in minutes) algorithm animation-style program views without requiring any sophisticated graphics knowledge and without using textual coding. Lens also is integrated with a system debugger to promote iterative design and exploration.