Abstract Interpretation of Student Programs as a Strategy for Courseware Development

What kinds of feedback can we give to students as part of a computer-based system for supporting programming? One kind of feedback is whether the idioms that students use in their programs are typical of experienced programmers. In this paper we talk about how such idioms/patterns/roles/clich303251s are used in a tacit fashion by experienced programmers, and how natural language tags for such idioms (e.g. roles of variables) can be used to articulate this knowledge. Based on these ideas we suggest a strategy for giving feedback to students in courseware: students annotate their program using an annotation language that captures these idioms; then abstract interpretation of programs is used by the courseware to check these annotations and provide focused feedback. As a case study, we show how roles of variables can be annotated and those annotations automatically checked in the BlueJ programming environment.