Domain Specific Languages (DSLs) are an old technique in softwaredevelopment that's getting a recent resurgence in interest. Mostdevelopers run into them regularly - as XMLconfiguration files, regular expressions, query languages or buildscripts. However they haven't been given the attention they deserve andthere is very little information out there to help developers build themeffectively. We find that few people have done much to build their ownDSLs and even fewer have a broad appreciation of the various techniquesinvolved.

This tutorial is a step towards closing this gap. We'll begin byintroducing the three main categories of DSLs: External, Internal, andLanguage Workbenches. We'll talk about the advantages of DSLs and theproblems in using them, so that you'll appreciate what the differentstyles look like and when you might want to build them. In the secondpart we'll go into more details on techniques of working with each ofthe three styles, to get you started on your own work.

We are currently working to develop a coherent pedagogic framework (ifyou'll forgive a pretentious name) for DSLs, this tutorial is anopportunity to catch up with our work. However it does come with acaveat: we are still very much in the middle of the process of capturingand organizing this knowledge. As a result we won't be describing afinished body of knowledge, but rather one that is still evolving.

Keywords: DSL, Domain Specific Language, Java, Groovy, Ruby, Intentional Software, MPS, C#, Languages, Hot topic, Patterns

Target audience: Any developer interested in the current thinking and state of the art in Domain Specific Languages. This tutorial encourages thinking beyond frameworks and API's, starting to think about fluency in computer languages, from both theoretical and practical standpoints.