Temporal event analysis and program understanding

A temporal event analysis approach to program understanding is described. Program understanding is viewed as a sequence of episodes in which the programmer concludes that an informal event occurs that corresponds to some part of the code. This can be viewed as accepting that the code is an adequate definition of the meaning of the informal event. Often, such a definition is contingent upon working hypotheses that describe other informal program properties that should be verified in order to confirm the validity of the understanding process. Verification of working hypotheses may depend on the formulation of additional definitions or working hypotheses. The understanding process can be assisted through the use of a documentation language for describing events and hypotheses, and a hypothesis verification tool. The paper describes a temporal event language in which hypotheses are formulated in terms of expected event sequences. A hypothesis verification tool was built, and experimentation was carried out on a set of programs. The tool was found to be very useful in understanding the detailed, control oriented aspects of a program. Program faults were discovered in every program that was analyzed, indicating that it facilitates a deep level of understanding