Declaration returns Declaration:  
	'var' name=ID ':' type = [Type];

var anInteger : Integer
var another : Integer

var anInteger, another : Integer

Declaration returns Declaration:  
	'var' name+=ID (',' name+=ID)* ':' type = [Type];

class IoTDSLDerivedState implements IDerivedStateComputer { 
  override discardDerivedState(DerivedStateAwareResource resource) {
    println("called discardDerivedState")
    resource.allContents.filter(typeof(DeclaredElement)).forEach [
      type = null
    ]
  }
  
  override installDerivedState(DerivedStateAwareResource resource, boolean preLinkingPhase) {
    println("called installDerivedState")
    resource.allContents.filter(typeof(DeclaredElement)).forEach [
      type = (eContainer as Declaration).type
    ]
  }
}

Declaration returns Declaration:
	'var' instances += DeclaredElement (',' instances += DeclaredElement)* ':' type = [Type]
;
DeclaredElement returns DeclaredElement:
  name=ID
;

class IoTDSLRuntimeModule extends AbstractIoTDSLRuntimeModule {	
  def bindIDerivedStateComputer() {
    // here is my derived state computer
    return IoTDSLDerivedState
  }

  override Class<? extends XtextResource> bindXtextResource() {
    return DerivedStateAwareResource;
  }

  def bindIResourceDescriptionManager() {
    return DerivedStateAwareResourceDescriptionManager;
  }
}

  def Class<? extends IDerivedStateComputer> bindIDerivedStateComputer() {
    return IoTDSLDerivedState
  }

  override Class<? extends XtextResource> bindXtextResource() {
    return DerivedStateAwareResource;
  }

  def Class<? extends IResourceDescription.Manager> bindIResourceDescriptionManager() {
    return DerivedStateAwareResourceDescriptionManager;
  }

public class IoTDSLExtendedGenerator extends XtextGenerator {  
  public IoTDSLExtendedGenerator() {    
    new XtextStandaloneSetup() {
      @Override
      public Injector createInjector() {
        return Guice.createInjector(new XtextRuntimeModule() {
          @Override
          public void configureIXtext2EcorePostProcessor(Binder binder) {
            try {
              Class.forName("org.eclipse.xtend.expression.ExecutionContext");
              binder.bind(IXtext2EcorePostProcessor.class).to(IoTDSLPostProcessor.class);
            } catch (ClassNotFoundException e) {
              logger.error(e.getMessage(), e);
            }
          }
        });
      }
    }.createInjectorAndDoEMFRegistration();
  }
}