A visual notation for succinct program traces

Program traces are a widely used representation for explaining the dynamic behavior of programs. They help to make sense of computations and also support the location and elimination of bugs. Unfortunately, program traces can grow quite big very quickly, even for small programs, which compromises their usefulness. In this paper we present a visual notation for program traces that supports their concise representation. We explain the design decisions of the notation and compare it in detail with several alternatives. An important part of the trace representation is its flexibility and adaptability, which allows users to transform traces by applying filters that capture common abstractions for trace representations. We also present an evaluation of the trace notation and filters on a set of standard examples. The results show that our representation can reduce the overall size of traces by at least 79%, which suggests that our notation is an effective improvement over the use of plain traces in the explanation of dynamic program behavior.