Visualizing Differences to Improve End-User Understanding of Trigger-Action Programs

Trigger-action programming lets end-users automate and connect IoT devices and online services through if-this-then-that rules. Early research demonstrated this paradigm's usability, but more recent work has highlighted complexities that arise in realistic scenarios. As users manually modify or debug their programs, or as they use recently proposed automated tools to the same end, they may struggle to understand how modifying a trigger-action program changes its ultimate behavior. To aid in this understanding, we prototype user interfaces that visualize differences between trigger-action programs in syntax, behavior, and properties.