Aligning development tools with the way programmers think about code changes

Software developers must modify their programs to keepup with changing requirements and designs. Often, aconceptually simple change can require numerous editsthat are similar but not identical, leading to errors andomissions. Researchers have designed programming environmentsto address this problem, but most of thesesystems are counter-intuitive and difficult to use.By applying a task-centered design process, we developeda visual tool that allows programmers to makecomplex code transformations in an intuitive manner.This approach uses a representation that aligns wellwith programmers' mental models of programming structures.The visual language combines textual and graphicalelements and is expressive enough to support a broadrange of code-changing tasks. To simplify learning thesystem, its user interface scaffolds construction and executionof transformations. An evaluation with Java programmerssuggests that the interface is intuitive, easyto learn, and effective on a representative editing task.