Abstract Program Visualisation: Object Orientation in the Tarraingim Program Exploratorium

Abstract

Program visualisation uses computer graphics and animation techniques to produce pictures illustrating the dynamic behaviour of a running computer program. Most program visualisation systems display either language-level details of programs or high-level overviews of the program's algorithm. This thesis investigates the use of abstraction in program visualisation. The goal of the project was to find techniques which could produce displays of programs at all levels of abstraction, and which would not require a large amount of information about the implementation of the program to be visualised. Based upon analyses of program visualisation and abstraction in programming, a model of abstract program visualisation is developed. This model uses object orientation to explicitly represent abstractions in the programs to be visualised. An object oriented framework for the design of an interactive program visualisation system (a program exploratorium) is developed based upon this model. This framework is used to construct Tarraingim, a prototype program exploratorium, as a proof of concept for the model. Tarraingim produces multiple views of object oriented programs at multiple levels of abstraction, by invisibly monitoring the programs' execution and using the information gathered to control graphical animations. Tarraingim is written in the SELF programming language, and visualises programs written in that language. A series of examples is presented to illustrate Tarraingim in action.