echebbi/standalone-xtext-example

Standalone xText example

This repository shows how to use xText in a standalone Java application.

In order to ease dependencies management, we'll use Maven. However, the same process can be applied to a Gradle or a pure Java project.

Disclaimer: the following explanations are based on xText 2.12.

Table of Contents

• 1. Create the xText projects
• 2. Generate xText artifacts
• 3. Build the grammar
• 4. Use xText in a standalone application

1. Create the xText projects

Within Eclipse, open the New xText Project with File > New > Other... > Xtext Project

Fill the fields as you wish then click on Next >.

Select Maven as Preferred Build System.

Click Finish to generate the different projects.

2. Generate xText artifacts

The next step is to launch the MWE2 workflow so that all Java classes required to parse a file are generated.

To this end, open the project containing the grammar, go into src and right-click on the Generate*.mwe2 file and choose Run As > MWE2 Workflow.

3. Build the grammar

Right-click on the root project (org.xtext.example.mydsl.parent) and choose Run As > Maven install.

Maven then runs and package the different projects into JAR files.

4. Use xText in a standalone application

Set up the dependencies

Create a new Maven project with the following dependencies:

<dependencies>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.10.0</version>
  </dependency>
  <dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.10.0</version>
  </dependency>
  <dependency>
    <groupId>org.eclipse.xtext</groupId>
    <artifactId>org.eclipse.xtext</artifactId>
    <version>2.12.0</version>
  </dependency>
</dependencies>

You must also add the JAR located under org.xtext.example.mydsl/target as a project's dependency.

Parse a file

First of all, create a file respecting the xText grammar then move it to the root of the project.

Then, create a simple main as follows:

public static void main(String[] args) {
	Injector injector = new MydslStandaloneSetupGenerated().createInjectorAndDoEMFRegistration();
	XtextResourceSet resourceSet = injector.getInstance(XtextResourceSet.class);
	Resource resource = resourceSet.getResource(URI.createFileURI("./example.mydsl"), true);

	Model model = (Model) resource.getContents().get(0);
	model.getGreetings().forEach(System.out::println);
}

You can now execute the class to parse your grammar with a standalone Java application.