---+++Language Definition and Extension with MPS ---+++++[[http://www.voelter.de/][Markus Völter]] ---++++++Abstract Language definition and extension is a hot topic. Using modular languages, where a program can use concepts from different language modules as needed, promises significantly increased language usability as well as an integration between general purpose (programming) and domain-specific (modeling) concepts and tools. !JetBrains MPS is an open source language workbench that uses projectional editing as opposed to parsing techniques. In MPS, languages are defined via structure, projection rules, transformation rules and type systems. In this tutorial I will provide a brief overview about how MPS works and what you can do with it. I will show how to build an external DSL, how to integrate the external DSL with Java, and how to extend an existing programming language with a new statement. To round it off, I will demo a non-trivial set of languages for embedded software development. 90% of the tutorial will be live demos. Note that even if you don't plan to work with MPS specifically, this tutorial will provide a good overview of projectional editing. ---++++++Author biography [[http://www.voelter.de/][Markus Völter]] works as an independent researcher, consultant and coach for itemis AG in Stuttgart, Germany. His focus is on software architecture, model-driven software development and domain specific languages as well as on product line engineering. Markus also regularly writes (articles, patterns, books) and speaks (trainings, conferences) on those subjects. Contact him via voelter@acm@org or www.voelter.de.