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

Debugging Xtend code


The Java code generated by Xtend is clean and easy to debug. However, it is also possible to debug Xtend code directly (instead of the generated Java), thanks to the complete integration of Xtend with the Eclipse JDT debugger.

This means that you can start debugging a Java application that at some point invokes Java code that has been generated by Xtend and, stepping through that, automatically brings you to debugging the original Xtend source. The next screenshot shows a debugging session of Xtend code. Note that all the JDT debugger views are available; furthermore, implicit variables such as it can be inspected in the Variables view:

You can also debug an Xtend file (for example, containing a main method) directly, since all the Run and Debug configuration launches are available for Xtend files as well. Breakpoints can be inserted in an Xtend file by double-clicking on the breakpoint ruler in the editor (currently, the Debug context menu is not available for Xtend files...