Book Image

Implementing Domain-Specific Languages with Xtext and Xtend - Second Edition

By : Lorenzo Bettini
4 (1)
Book Image

Implementing Domain-Specific Languages with Xtext and Xtend - Second Edition

4 (1)
By: Lorenzo Bettini

Overview of this book

Xtext is an open source Eclipse framework for implementing domain-specific languages together with IDE functionalities. It lets you implement languages really quickly; most of all, it covers all aspects of a complete language infrastructure, including the parser, code generator, interpreter, and more. This book will enable you to implement Domain Specific Languages (DSL) efficiently, together with their IDE tooling, with Xtext and Xtend. Opening with brief coverage of Xtext features involved in 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. You will then explore the typical programming development workflow with Xtext when we modify the grammar of the DSL. Further, the Xtend programming language (a fully-featured Java-like language tightly integrated with Java) will be introduced. We then explain the main concepts of Xtext, such as validation, code generation, and customizations of runtime and UI aspects. You will have learned how to test a DSL implemented in Xtext with JUnit and will progress to advanced concepts such as type checking and scoping. You will then integrate the typical Continuous Integration systems built in to Xtext DSLs and familiarize yourself with Xbase. By the end of the book, you will manually maintain the EMF model for an Xtext DSL and will see how an Xtext DSL can also be used in IntelliJ.
Table of Contents (25 chapters)
Implementing Domain-Specific Languages with Xtext and Xtend - Second Edition
Credits
Foreword
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface
Preface to the second edition
14
Conclusions
Bibliography
Index

Dealing with super


As a final feature, we add the mechanism for invoking the implementation of a method in the superclass using the keyword super. Note that super should be used only as the receiver of a member selection expression, that is, it cannot be passed as the argument of a method. Following the practice "loose grammar, strict validation", we do not impose this at the grammar level. Thus, we add the rule for super as a terminal expression:

SJTerminalExpression returns SJExpression:
   ...
   {SJSuper} 'super' | ...

We add a validator rule that checks the correct super usage:

public static val WRONG_SUPER_USAGE =
  ISSUE_CODE_PREFIX + "WrongSuperUsage"

@Check def void checkSuper(SJSuper s) {
  if (s.eContainingFeature !=
        SmallJavaPackage.eINSTANCE.SJMemberSelection_Receiver)
    error("'super' can be used only as member selection receiver",
      null, WRONG_SUPER_USAGE)
}

Thanks to the way we implemented the scope provider, in order to make members of the superclass visible...