Using background colors to support program comprehension in software product lines

Background: Software product line engineering provides an effective mechanism to implement variable software. However, the usage of preprocessors, which is typical in industry, is heavily criticized, because it often leads to obfuscated code. Using background colors to support comprehensibility has shown effective, however, scalability to large software product lines (SPLs) is questionable. Aim: Our goal is to implement and evaluate scalable usage of background colors for industrial-sized SPLs. Method: We designed and implemented scalable concepts in a tool called FeatureCommander. To evaluate its effectiveness, we conducted a controlled experiment with a large real-world SPL with over 160,000 lines of code and 340 features. We used a within-subjects design with treatments colors and no colors. We compared correctness and response time of tasks for both treatments. Results: For certain kinds of tasks, background colors improve program comprehension. Furthermore, subjects generally favor background colors. Conclusion: We show that background colors can improve program comprehension in large SPLs. Based on these encouraging results, we will continue our work improving program comprehension in large SPLs.