Following the principles of Model-Driven Engineering and Language-Oriented Programming, Domain-Specific Languages (DSLs) are now developed in numerous domains to address specific concerns in the development of complex systems. However, despite many advances in Software Language Engineering, DSLs and their tooling still suffer from substantial development costs which hamper their successful adoption in the industry.We identify two main challenges to be addressed. First, the proliferation of independently developed and constantly evolving DSLs raises the problem of interoperability between similar languages and environments. Language users must be given the flexibility to open and manipulate their models using different variants and versions ...