Understanding Common Scratch Programming Idioms and Their Impact on Project Remixing

As Scratch has become one of the most popular educational programming languages, understanding its common programming idioms can benefit both computing educators and learners. This understanding can fine-tune the curricular development to help learners master the fundamentals of writing idiomatic code in their programming pursuits. Unfortunately, the research community's understanding of what constitutes idiomatic Scratch code has been limited. To help bridge this knowledge gap, we systematically identified idioms as based on canonical source code, presented in widely available educational materials.

We implemented a tool that automatically detects these idioms to assess their prevalence within a large dataset of over 70K Scratch projects in different demographic and project categories. Since communal learning and the practice of remixing are one of the cornerstones of the Scratch programming community, we studied the relationship between common programming idioms and remixes.

Having analyzed the original projects and their remixes, we observed that different idioms may associate with dissimilar types of code changes. Code changes in remixes are desirable, as they require a meaningful programming effort that spurs the learning process. The ability to substantially change a project in its remixes hinges on the project's code being easy to understand and modify. Our findings suggest that the presence of certain common idioms can indeed positively impact the degree of code changes in remixes. Our findings can help form a foundation of what comprises common Scratch programming idioms, thus benefiting both introductory computing education and Scratch programming tools.