Behavior-based clustering of visual code

A perennial problem with online repositories of end-user programmers' code is the low level of reuse, including in situations where existing code might aid in learning. This paper presents a formative study of middle-schoolers learning the Scratch animation environment, which revealed that they struggled to find short pieces of code that they could reuse directly, or from which they could discover language primitives (language instructions) to implement desired behavior. In response, we present a model and supporting prototype tool for clustering behaviorally similar code together, as a basis for helping end-user programmers to locate code. We conducted an empirical study confirming that our tool's model for estimating code similarity does correspond well with programmers' perceptions of code's behavioral similarity. Future work will expand on these results by providing new search engines that help end-user programmers to find and reuse visual code from online repositories.