Build your own Language: Why and How?

Are you responsible for developing satellite on-board software? Are you the Dutch government and you have to efficiently implement the public benefits law? Are you a healthcare startup, developing companion apps that help patients through a treatment? Are you an insurance company struggling to create new, and evolve existing products quickly to keep up with the market? These are all examples of organisations who have built their own domain-specific programming language to streamline the development of applications that have a non-trivial algorithmic core. All have built their languages with Jetbrains MPS, an open source language development tool optimized for ecosystems of collaborating languages with mixed graphical, textual, tabular and mathematical notations. This talk has four parts. I start by motivating the need for DSLs based on real-world examples, including the ones above. I will then present a few high-level design practices that guide our language development work. Third, I will develop a simple language extension to give you a feel for how MPS works. And finally, I will point you to things you can read to get you started with your own language development practice.