SrcSpecification:
    elements+=SrcElement*

SrcElement:
    SrcDeclaration | SrcReference

SrcDeclaration:
    "decl" name=ID

SrcReference:
    "ref" ref=[SrcDeclaration]

DstSpecification:
    elements+=DstElement*

DstElement:
    DstDeclaration | DstReference

DstDeclaration:
    "decl" name=ID

DstReference:
    "ref" ref=[DstDeclaration]

// ...
Workflow {

    component = XtextGenerator {
        // ...
        // the usual workflow configurations for an xtext-language
        // ...

        language = XtextGeneratorLanguage {
			name = "org.example.mydsl.DstModel"	
			fileExtensions = "dstmodel"
			
			fragment = ecore.EMFGeneratorFragment2 {}
			fragment = resourceFactory.ResourceFactoryFragment2 {}
		}
    }
}

@singleton
class ResourceSetCreator {

    @Inject IResourceFactory resourceFactory
    @Inject IResourceServiceProvider serviceProvider 
    @Inject XtextResourceSet resourceSet

    def void registerExtension(String ext) {
		Resource.Factory.Registry.INSTANCE.getExtensionToFactoryMap().put(ext, resourceFactory)
		IResourceServiceProvider.Registry.INSTANCE.getExtensionToFactoryMap().put(ext, serviceProvider)
    }

    def Resource createResource(URI uri) {
        return resourceSet.createResource(uri)
    }

    def void resolve() {
        EcoreUtil2.resolveAll(resourceSet)
    }
}

//...

@Inject extension IQualifiedNameProvider 
@Inject ResourceSetCreator resourceSetCreator

override void doGenerate(Resource resource, IFileSystemAccess2 fsa, IGeneratorContext context) {

    resourceSetCreator.registerExtension("dstmodel")

    val generatedResources = newArrayList()

    for (srcSpec: resource.contents.filter(SrcSpecification)) {

        val dstResource = resourceSetCreator.createResource(srcSpec.fullyQualifiedName.toString("/") + ".dstmodel")

        val transformedSpec = transformSrcSpecification(srcSpec)

        dstResource.contents.add(transformedSpec)

        generatedResources+=dstResource

    }

    resourceSetCreator.resolve()
}

def DstSpecification transformSrcSpecification(SrcSpecification srcSpec) {

    for (elem: srcSpec.elements) {

        switch(elem) {
            SrcDeclaration: transformSrcDeclaration(elem)
            SrcReference: transformSrcReference(elem)
        }
    }
}

def DstDeclaration transformSrcDeclaration(SrcDeclaration decl) {
    FACTORY.createDstDeclaration => [
        name = decl.name
    ]
}

def DstReference transformSrcReference(SrcReference ref) {

    val proxy = EcoreUtil2.create(FACTORY.createDstDeclaration.eClass) as InternalEObject
    proxy.eSetProxyURI(URI.createURI(ref.fullyQualifiedName.toString(".")))

    FACTORY.createDstReference => [
        ref = proxy as DstDeclaration
    ]

}

// ...