Aharon Abadi - Fine Slicing for Advanced Method Extraction

The potential of the Extract Method refactoring for maintaining high-quality software is well-recognized. It can be useful by itself, or as a building block in larger refactoring tasks. Because it requires a deep analysis of data and control dependences, it is difficult to perform correctly without tools in complicated cases. Unfortunately, refactoring tools do not perform the required analysis, and will fail in or reject such cases. Some very useful cases, such as those involving non-contiguous code, cannot even be expressed using these tools’ interfaces. We present a new refactoring to untangle desired computations from their surrounding code, in preparation for Extract Method. It is based on the concept of fine slicing, which is a method for computing program slices that can be tailored by the removal of some data and controld ependences. Fine slices are executable and extractable from their surrounding code. Fine slices can also be used to compute co-slices, the part of the program that should be left behind when extracting a fine slice. This is crucial for the ability to reuse the extracted slice from the original code.