Generic Semantics of Feature Diagrams Variants

A large number of extensions of Feature Oriented Domain Analysis (FODA) Feature Diagrams were introduced to compensate for a purported ambiguity and lack of precision and expressiveness of the original FODA feature diagrams (OFD). However, they never received a formal semantics, which is the hallmark of precision and unambiguity. We propose here a formal semantics for all these diagrams, thanks to a generic construction that we call Free Feature Diagrams (FFD). From this we demonstrate that OFD are precise, unambiguous, and expressively complete, and thus that all extensions add no expressiveness. A finer notion is thus needed to compare these languages. Two solutions are well-established: succinctness and embeddability, that express naturalness of a language. This tool shows that some extensions indeed bring some naturalness, but are harmfully redundant and that the same naturalness can be attained with the simpler varied FD (VFD).