Incremental Code Clone Detection and Elimination for Erlang Programs

A well-known bad code smell in refactoring and software maintenance is the existence of code clones, which are code fragments that are identical or similar to one another. This paper describes an approach to incrementally detecting 'similar' code based on the notion of least-general common abstraction, or anti-unification, as well as a framework for user-controlled incremental elimination of code clones within the context of Erlang programs. The clone detection algorithm proposed in this paper achieves 100 precision, high recall rate, and is user-customisable regarding the granularity of the clone classes reported. By detecting and eliminating clones in an incremental way, we make it possible for the tool to be used in an interactive way even with large codebases. Both the clone detection and elimination functionalities are integrated with Wrangler, a tool for interactive refactoring of Erlang programs. We evaluate the approach with various case studies.