An Automatic Layout Algorithm for Lograph

We present a layout algorithm for the Lograph debugger which automatically rearranges a Lograph query graph at run time in response to the application of Lograph rules by the interpreter. The algorithm addresses certain cognitive issues, aiming to make the execution of query graphs more comprehensible. It incorporates a foresighted graph adjustment technique that improves the layout of a query by searching for data structure patterns and looking ahead in the execution. The look-ahead attempts to decrease the expected future changes in the layout by leaning the current layout towards one that would require less modifications in the next few execution steps. The execution of a program in the debugger can be observed as a smooth transformation to a solution graph from a query graph, the layout of which is created by the user.