Code Transformation by Direct Transformation of ASTs

International audienceSoftware evolves to be adapted to the environment, due to bugs, new features and design changes. Code transformations can be done manually, but that is a tedious and error-prone task. Therefore automated tools are used to assist developers in this maintenance operation. The Pharo environment includes its own refactoring tool — the Rewrite Engine — that allows one to transform methods by directly specifying parts of the AST to be rewritten. In addition, it proposes a parse tree transformation engine. However this tool and the used DSL to express the patterns for matching and transforming trees are complex to understand and master. In this context, writing a transformation rule is not a trivial task. We present a graphical tool built on the top of the Rewrite Engine — the Rewrite Tool — that abstracts the creation of transformation rules and proposes high-level AST operations that are simpler to understand than syntactic descriptions. It helps to automate the process of code transformation with a user-friendly interface