Book Image

Implementing Domain-Specific Languages with Xtext and Xtend

By : Lorenzo Bettini
Book Image

Implementing Domain-Specific Languages with Xtext and Xtend

By: Lorenzo Bettini

Overview of this book

Xtext is an open source Eclipse framework for implementing domain-specific languages together with its IDE functionalities. It lets you implement languages really quickly, and, most of all, it covers all aspects of a complete language infrastructure, starting from the parser, code generator, interpreter, and more. "Implementing Domain-Specific Languages with Xtext and Xtend" will teach you how to develop a DSL with Xtext, an Eclipse framework for implementing domain-specific languages. The chapters are like tutorials that describe the main concepts of Xtext such as grammar definition, validation, code generation, customizations, and many more, through uncomplicated and easy-to-understand examples. Starting with briefly covering the features of Xtext that are involved in a DSL implementation, including integration in an IDE, the book will then introduce you to Xtend as this language will be used in all the examples throughout the book. We then proceed by explaining the main concepts of Xtext, such as validation, code generation, and customizations of runtime and UI aspects. By the end of the book, you will have learned how to test a DSL implemented in Xtext with Junit, in order to follow a test-driven development strategy that will help the developer implement maintainable code that is much faster and cleaner. A test-driven approach is used throughout the book when presenting advanced concepts such as type checking and scoping. The book also shows you how to build and release a DSL so that it can be installed in Eclipse, and gives you hints on how to build the DSL headlessly in a continuous integration server. "Implementing Domain-Specific Languages with Xtext and Xtend" aims to complement the official Xtext documentation to explain the main concepts through simplified examples and to teach the best practices for a DSL implementation in Xtext. It is a Beginner's Guide which should set you up for professional development DSL and its Eclipse IDE tooling.
Table of Contents (21 chapters)
Implementing Domain-Specific Languages with Xtext and Xtend
Credits
About the Author
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
13
Bibliography
Index

Introduction to code generation


After a program written in your DSL has been parsed and validated, you might want to do something with the parsed EMF model, that is, the AST of that program. Typically, you may want to generate code in another language (for example, Java code), a configuration file, XML, a text file, and so on. In all of these cases, you will need to write a code generator.

Since the parsed program is an EMF model, you can indeed use any EMF framework which somehow deals with code generation. Of course, you might also use plain Java to generate code, after all, as we saw in the previous chapters, you have all the Java APIs to access the EMF model.

However, in this book, we will use Xtend (introduced in Chapter 3, The Xtend Programming Language) to write code generators, since it is very well suited for the task. Moreover, the task of writing a code generator is greatly simplified by the fact that Xtext automatically integrates your code generator into the Eclipse build infrastructure...