Comprehending and visualizing software based on XML-representations and call graphs

We have implemented a package VISUR/RAR in XPCE/SWI-PROLOG, which provides some further functionality of an integrated development environments (IDE): it allows for the visualization of rules (VISUR) together with the reasoning about rule structures (RAR). VISUR/RAR is part of the toolbox DISLOG, which is also developed under XPCE/SWI-PROLOG; the functionality of DISLOG ranges from reasoning in disjunctive deductive databases to applications such as the management and visualization of stock information. The deductive database of RAR manages rules for analyzing PROLOG-code based on suitable dependency graphs and rules for recovering the design of PROLOG- and JAVA-software using a query language FNQUERY for XML-representations, which we have developed. It can be applied for improving the design of rule-based systems, for computing certain software metrics, and for supporting refactoring techniques. The obtained results can be visualized using graphs and tables in VISUR.