Automating repetitive code changes using examples

Abstract

While adding features, fixing bugs, or refactoring the code, developers may perform repetitive code edits. Although Integrated Development Environments (IDEs) automate some transformations such as renaming, many repetitive edits are performed manually, which is error-prone and time-consuming. To help developers to apply these edits, we propose a technique to perform repetitive edits using examples. The technique receives as input the source code before and after the developer edits some target locations of the change and produces as output the top-ranked program transformation that can be applied to edit the remaining target locations in the codebase. The technique uses a state-of-the-art program synthesis methodology and has three main components: a) a DSL for describing program transformations; b) synthesis algorithms to learn program transformations in this DSL; c) ranking algorithms to select the program transformation with the higher probability of performing the desired repetitive edit. In our preliminary evaluation, in a dataset of 59 repetitive edit cases taken from real C# source code repositories, the technique performed, in 83% of the cases, the intended transformation using only 2.8 examples.