Visualizing program execution

The motivation for this work stems from the lack of good visual tools for describing the execution of procedure-level constructs such as procedures, functions, coroutines, iterators, methods, and processes. Our proposed solution to this problem is an extension of an old technique called the contour diagram, which was originally used to give semantics for Algol-like languages. Our extensions allow the contour diagram to be used for more modern languages, such as object-oriented languages, logic languages, etc. In this paper, we explain this extended notation, and its use in visualizing the execution of procedural, object-oriented and logic programs. The significance of this extension is that it can serve as a basis for program visualization tools.