Source-Based Trace Exploration

Tracing a computation is a key method for program comprehension and debugging. Hat is a tracing system for Haskell 98 programs. During a computation a trace is recorded in a file; then the user studies the trace with a collection of viewing tools. Different views are complementary and can productively be used together. Experience shows that users of the viewing tools find it hard to keep orientation and navigate to a point of interest in the trace. Hence this paper describes a new viewing tool where navigation through the trace is based on the program source. The tool combines ideas from algorithmic debugging, traditional stepping debuggers and dynamic program slicing.