FeatureCoPP: compositional annotations.

Software product lines can be implemented with different techniques. Those techniques can be grouped into annotation-based and composition-based approaches, with complementary strengths and weaknesses. A combination seems useful to utilize benefits of both groups but using two techniques in parallel may cause new problems. To our knowledge, there is no approach that integrates composition into an annotation-based approach or vice versa. We propose the use of an extended preprocessor to introduce physical separation of concerns similar to feature-oriented programming. In this paper, we i) present a preliminary implementation that integrates composition into annotation, ii) analyse its benefits and shortcomings, and iii) discuss implementation and tooling. Overall, we enable developers to keep on using familiar preprocessors but also to benefit from composition. Finally, we show the potential of our approach.