Enriching block-based end-user programming with visual features

Today, most programmers are not professional software developers, but end-users with limited training and experience in programming. End-user-friendly programming languages and tools aim to support this type of user, and many use visual programming aids to do so. Block-based programming is a popular visual programming style that has been effectively used in computer science education and is the foundation for many modern end-user programming tools. Because of the popularity of block-based programming, language designers can use a rich set of existing technologies that save them the effort of creating visual programming designs from scratch. However, many language designers ignore that block-based programming was created with learners in mind, who have different needs than end-users. Especially when programs grow in size and complexity, blocks offer little support to help end-users understand and edit programs effectively. In our work, we augment block-based programming with visual features that extend the range of programs that end-users can comprehend and write. In particular, we create languages and environments for the domain of robotics programming that allow end-users to write larger and more expressive programs. We focus on three scenarios that represent challenges that end-users face in this domain: coordinating multiple robots that work in tandem, writing large programs that span several workstations in different locations, and reacting to external signals such as machines or user interactions. For each environment, we first discuss the limitations of existing work in the areas of block-based and end-user programming. We present and discuss the design of our visual extensions with the goal to maintain end-user-friendliness. Finally, we evaluate our work through empirical studies, both formative to inform our designs and summative to demonstrate their benefits. Our designs, and the empirical and analytical process that we applied to create them, both contribute to a stronger understanding of how to build end-user-centric tools. We further believe that although our work focuses on the domain of robotics, these contributions transfer to other areas of end-user programming as well.Science, Faculty ofComputer Science, Department ofGraduat