Evolving the DarTwin evolution language

DarTwin is a notation for describing and planning evolution of digital twin systems. Originally conceived as a graphical notation, DarTwin has evolved into a domain-specific language formally defined in SysML v2. This evolution exposed challenges related to graphical notation support, tooling interoperability, and co-evolution between notation, language definition, and modelling environments. We experienced that SysML v2 tooling was not adequate to provide our DarTwin graphical notation even with some post-processing. The SysML v2 definition of DarTwin did, however, motivate improvements of the DarTwin DSL. To provide fruitful DarTwin graphical notation and still maintain the formal definition in SysML v2 we demonstrate how domain-specific tooling (MetaEdit+) helps improving the graphic editing and rendering support and thus achieve a more effective and intuitive use of DarTwin. By generating SysML v2 from MetaEdit+ we preserve the connection between the adequate graphical notation and the precision and formality of DarTwin. The combined DarTwin tooling made the methodology to apply general evolution transition patterns (DarTrans) more formal and precise while still intuitive through graphic notation using colour and dashes. This in turn motivated enhancing the DarTwin language by adding concepts related to the evolution transitions to facilitate discovering and documenting the transitions.