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

Integration with the Eclipse build mechanism


It is time to see our generator in action: launch Eclipse, create a Java project in the workspace, and, in the src folder, create a new .entities file (remember to accept to add the Xtext nature to the project, otherwise the generator will not run). Continue by adding one or more entities with some attributes. Notice that a src-gen folder is automatically created as soon as you save the file. At this point, you should also add this generated folder to the projects source folders by going to Build Path | Use as Source Folder. Exploring the content of the src-gen folder you will find a generated Java class for each entity in your .entities file. You can see an example in the following screenshot.

Note

Observe that a code generator just creates text. Other components have to make sense of that, for example, a Java compiler. That is why we need to add the src-gen folder to the project source folders: this way, the Eclipse Java compiler automatically...