A Debugging Approach for Trigger-Action Programming

Nowadays, end users can customize their technological devices and web applications by means of trigger-action rules, defined through End-User Development (EUD) tools. However, debugging capabilities are important missing features in these tools that limit their large-scale adoption. Problems in trigger-action rules, in fact, can lead to unpredictable behaviors and security issues, e.g., a door that is unexpectedly unlocked. In this paper, we present a novel debugging approach for trigger-action programming. The goal is to assists end users during the composition of trigger-action rules by: a) highlighting possible problems that the rules may generate, and b) allowing their step-by-step simulation. The approach, based on Semantic Web and Petri Nets, has been implemented in a EUD tool, and it has been preliminary evaluated in a user study with 6 participants. Results provide evidence that the tool is usable, and it helps users in understanding and identifying problems in trigger-action rules.