DomainModel:
	(elements+=AbstractElements)*;
	
AbstractElements :
	Cars | Animal | MyCarDescription | MyPetDescription;

Cars :
 'brand :' name=ID '{'
 	(elements+=CarType)*
 	'}'
 ;
 	
CarType:
 'type ' name=ID;

 Animal :
 'species ' name=ID '{'
 	(elements+=PetName)*
 	'}'
 	;
 	
 PetName :
 	'Pet name :' name=ID;
 	
 MyCarDescription :
 'I own a ' myCar=[Cars] 'of type ' myCarType=[CarType];
 
 MyPetDescription :
 'My Pet is a ' myPet=[Animal]', his/her name is ' myPetName =[PetName];

brand : Chrysler {
type Voyager
type Horizon
}

brand : Toyota {
type Hybrid
type Yaris
}

species Dog {
Pet name : Zeus
Pet name : Appolon
}

species Cat {
Pet name : Lilou
Pet name : Zoe
}

I own a Chrysler of type ______

My Pet is a Dog , his/her name is ______

public class MyDslScopeProvider extends AbstractDeclarativeScopeProvider {
	
	public IScope scope_MyCarDescription_myCarType(MyCarDescription mcd, EReference ref) {
		return Scopes.scopeFor(mcd.getMyCar().getElements());
	}

}

BrandDescription : 
 'For the car brand ' brandname=[Cars] ', the following colored types exist : '
 	(elements+=ColorCarTypeDefinition)+
 ;
 
 ColorCarTypeDefinition :
 	coloredcartype=[CarType] ' = ' color=ID 	;

	// Gives scope to editor validator but not to content-assist, why ?
	public IScope scope_ColorCarTypeDefinition_coloredcartype(ColorCarTypeDefinition colorCarTypeDefinition, EReference ref) {
		return Scopes.scopeFor(((BrandDescription)colorCarTypeDefinition.eContainer()).getBrandname().getElements());	
	}

For the car brand Chrysler , the following colored types exist : 
Voyager = blue
Horizon = red
Hybrid = yellow

package org.xtext.example.mydsl.ui.contentassist;

import org.eclipse.emf.ecore.EObject;
import org.eclipse.xtext.*;
import org.eclipse.xtext.common.ui.contentassist.TerminalsProposalProvider;
import org.eclipse.xtext.ui.editor.contentassist.ICompletionProposalAcceptor;
import org.eclipse.xtext.ui.editor.contentassist.ContentAssistContext;

/**
 * Represents a generated, default implementation of interface {@link IProposalProvider}.
 * Methods are dynamically dispatched on the first parameter, i.e., you can override them 
 * with a more concrete subtype. 
 */
public class AbstractMyDslProposalProvider extends TerminalsProposalProvider {
		


...

	public void completeColorCarTypeDefinition_Coloredcartype(EObject model, Assignment assignment, ContentAssistContext context, ICompletionProposalAcceptor acceptor) {
		lookupCrossReference(((CrossReference)assignment.getTerminal()), context, acceptor);
	}
	public void completeColorCarTypeDefinition_Color(EObject model, Assignment assignment, ContentAssistContext context, ICompletionProposalAcceptor acceptor) {
		completeRuleCall(((RuleCall)assignment.getTerminal()), context, acceptor);
	}

...

	public void complete_ColorCarTypeDefinition(EObject model, RuleCall ruleCall, ContentAssistContext context, ICompletionProposalAcceptor acceptor) {
		// subclasses may override
	}
}

	public IScope scope_ColorCarTypeDefinition_coloredcartype(EObject context, EReference ref) {
		BrandDescription b=extractBrandDescriptionFromContext(context);
		return Scopes.scopeFor(b.getBrandname().getElements());
		}

	private BrandDescription extractBrandDescriptionFromContext(EObject context) {
		return (BrandDescription) context.eContainer();
	}