(2) Research on Visual Interface of KLIC

"Graph drawing algorithm" and "Animated visualization" are very useful to visualize klic program. Our goal is propose a visual programming system which integrate "Programming," "Debugging," and "Execution". For this goal, we present a new improved graph drawing algorithm for the undirected graph, especially suited for the program animation. We have implemented program visualization system "viewPP," which visualizes klic program execution. - About graph drawing algorithm - "klic" program can be expressed by the graph structure. An edge indicates a variable. A node indicates an atom, a predicate or a functor. Our improved algorithm is based on the "Spring model". We have modified "Eades spring model" and invented the new graph drawing algorithm which are suited for the animated graph replacement. Eades spring model uses an attractive force and a repulsive force. We have modified a repulsive force expression the for animation-like graph replacement. - About visual programming system - For integrating GUI into klic program, we have implemented a klic <-> Tcl/Tk interface program "klitcl", and released it as ICOT Free Software. We can attach GUI into klic application program easily. We have implemented the system "viewPP" for visualizing klic program execution. This system uses the improved algorithm for the visualization of klic program. "klitcl" is used for GUI of "viewPP". "viewPP" realizes the klic program execution with 2D graphics and animation.