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

Classes of the same package


Just like in Java, SmallJava classes should be able to refer to external classes in the same package without importing the package. However, this is not yet the case in the current implementation. For example, given the following two SmallJava files, they are not able to refer to each other without an explicit import, although they are in the same package:

// first file
package my.pack;

class A {
  B b;
}

// second file
package my.pack;

class B extends A {}

To solve this problem, we need to go back to our custom SmallJavaImportedNamespaceAwareLocalScopeProvider that we implemented in section Default imports. The idea is to customize internalGetImportedNamespaceResolvers so that when the context is a SmallJava program then we add an implicit import of the same package of the current SmallJava program, if the program has a package.

To do that, we create an ImportNormalizer. We have already used ImportNormalizer in section Default imports. This is the implementation...