Program visualization may be viewed as a mapping from programs to graphical representations. This simple idea provides a formal framework for a new taxonomy of program visualization systems. The taxonomy is compared briefly against previous attempts to organize the program visualization field. The taxonomic principles and their motivation are explained in detail with reference to a number of existing systems, especially Balsa, Tango, and Pavane.

Until now, only users of textual programming languages have enjoyed the fruits of algorithm animation. Users of visual programming languages (VPLs) have been deprived of the unique semantic insights algorithm animation offers, insights that would foster the understanding and debugging of visual programs. To begin solving this shortcoming, we have seamlessly integrated algorithm animation capabilities into Forms/3, a declarative VPL in which evaluation is the continuous maintenance of a network of one-way constraints. Our results show that a VPL that uses this constraint-based evaluation model can provide features not found in other algorithm animation systems. 1: Introduction Algorithm animation is a type of software visualization of growing importance. It is a dynamic visualization of the main abstractions of a program's underlying algorithm. The value of algorithm animation lies in its ability to portray the essence of the program's logic, avoiding the obscuring of this essence tha...

Parallel and distributed programming is intrinsically more difficult than sequential programming, yet few effective tools or methodologies have been developed to help programmers understand the behavior of their parallel programs. Browsing source code and tracing program output are tedious and often ineffective approaches for parallel program understanding. Program visualization, which relates a program's behavior to the programmer's model of the system's components and interactions, has been shown to be a novel and highly effective approach to program and algorithm comprehension. Extending and adapting program visualization to parallel programming can aid comprehension of the complex concurrent events and transitions that occur in parallel programs. We are defining a model for the capture and display of parallel program events and transitions, based upon the path-transition paradigm for animation, and partial ordering of events. Using this model, we are developing a prototype for vis...

Specifying varying speeds and temporal relationships is necessary when programming graphical animations, but support for temporal programming has usually been done by adding new language features to a VPL, and these features must be mastered over and above the other aspects of the VPL. However, some researchers have believed that time should be able to be treated like just another dimension. In this paper, we explore whether temporal programming can indeed be done using exactly the same devices as in spatial programming in grid-oriented VPLs. Toward this end, we provide a continuum of models aimed at this goal, with their advantages and disadvantages. Also, we identify core issues that help illuminate the essence of the problem.

The general term program visualization refers to graphical views or illustrations of the entities and characteristics of computer programs. This term along with many others including data structure display, program animation, algorithm animation, etc., have been used inconsistently in the literature, which has led to confusion in describing systems providing these capabilities. In this paper we present a scaled characterization of program visualization terms along aspect, abstractness, animation, and automation dimensions. Rather than placing existing systems into hard-and-fast categories, we focus on unique and differentiating aspects across all systems. Keywords: program visualization, algorithm animation, software understanding 1 Introduction A visualization tool provides graphical views of the entities and characteristics of a computer system or program. The purpose of such a visualization tool is stated nicely by Myers, et. al.: "Human information processing is clearly optimized...

Algorithm animation systems and graphical debuggers perform the task of translating program state into visual representations. While algorithm animations typically rely on user augmented source code to produce visualizations, debuggers make use of symbolic information in the target program. As a result, visualizations produced by debuggers often lack important semantic content, making them inferior to algorithm animation systems. This paper presents a method to provide higher-level, more informative visualizations in a debugger using a technique called traversal-based visualization. The debugger traverses a data structure using a set of user-supplied patterns to identify parts of the data structure to be drawn a similar way. A declarative language is used to specify the patterns and the actions to take when the patterns are encountered. Alternatively, the user can construct traversal specifications through a graphical user interface to the declarative language. Furthermore, the debugge...

How might capabilities for algorithm animation be seamlessly integrated into a programming language that is both visual and declarative? Until now, visual programming language researchers have not attempted to anwer that question, making the fruits of algorithm animation available only to users of textual programming languages. Users of visual programming languages (VPLs) have been deprived of the unique semantic insights algorithm animation offers, insights that would foster the understanding and debugging of visual programs.

In this paper program visualization is defined as a mapping from programs to graphical representations. Simple forms of program visualization are frequently encountered in software engineering. For this reason current advances in program visualization are likely to influence future developments concerning software engineering tools and environments. This paper provides a new taxonomy of program visualization research. The proposed taxonomy becomes the vehicle through which we carry out a systematic review of current systems, techniques, trends, and ideas in program visualization.