|
UDC 004.4'426
Daniela da Cruz 1,
Pedro Rangel Henriques
1, and Maria Joao
Varanda Pereira 2
1 University of
Minho - Department of
Computer Science,
Campus de Gualtar, 4715-057,
Braga, Portugal
{danieladacruz,prh}@di.uminho.pt
2 Polytechnic
Institute of Braganca
Campus de Sta. Apolonia,
Apartado 134 - 5301-857,
Braganca, Portugal
mjoao@ipb.pt
Abstract.
The aim of this paper is to discuss how our
pattern-based strategy for the visualization of data
and control flow can effectively be used to animate
the program and exhibit its behavior. That result
allows us to propose its use for Program
Comprehension. The animator uses well known compiler
techniques to inspect the source code in order to
extract the necessary information to visualize it
and understand program execution. We convert the
source program into an internal decorated (or
attributed) abstract syntax tree and then we
visualize the structure by traversing it, and
applying visualization rules at each node according
to a pre-defined rule-base. In order to calculate
the next step in the program execution, a set of
rewriting rules are applied to the tree. The
visualization of this new tree is shown and the
program animation is constructed using an iterative
process. No changes are made in the source code, and
the execution is simulated step by step.
Several examples
of visualization are shown to illustrate the
approach and support our idea of applying it in the
context of a Program Comprehension environment.
|
Pdf