Markus Völter, Independent Consultant

External Textual DSLs are a sweet spot in DSL-land: their textual nature allows for simple integration with existing development infrastructures (such as CVS or SVN). Being external, they are not limited by the syntax of a host language and can provide static ("compile time") error checking. Traditionally, the drawback of this kind of DSL was that the construction of the grammar and a fancy editor was quite a lot of work.

In this session I will briefly talk about the tradeoffs between textual/graphical/internal/external DSLs and then proceed to build a textual DSL, complete with a syntax coloring, code completing and constraint checking editor. We will then look at how to process the "program" written in the DSL by either writing a compiler (aka code generator) and an interpreter.

The goal of the session is to convince the audience that building an external textual DSL is easier and better than working with XML! The examples will use Eclipse TMF/openArchitectureWare tooling.

In this tutorial I will provide a hands-on introduction to building textual DSLs with Eclipse tools (and yes, you can follow along on your own machine, if you like).

I will start with a very short introduction to DSLs and will explain where and how the tutorial content fits into the grand scheme of DSLs in general. I will continue with a brief introduction to Eclipse Modeling in general and provide an overview over the capabilities of Eclipse-based DSL tooling (to let you know about all of the stuff we cannot cover in the tutorial because there isn't enough time). The last part of the theoretical introduction  will cover some important best practices regarding DSLs.

We will then spend the majority of the tutorial time building an external textual DSL. The created tooling will include a convenient editor with syntax coloring, code completion and error checking. In the next step we will build a code generator to create executable artefacts from the DSL "programs". We will also look at how to build an interpreter as an alternative means of execution.

The goal of this full-day tutorial is to ensure you are able to build your own DSLs (including tools to process the "programs") in a reasonable amount of time. This will make developing your own DSLs in real-life projects a practical reality.