Model
	Document (n)
		Data
			Field (n)
		UI
			define UI with references to Fields

Model returns Model: 
	documents+=Document 
;
Document returns Document :
	data=Data
;
Data returns Data: 
	("Fields" "{"
		(fields+=Field)+
	"}")*
	(groups+=Group)+
;
....some more stuff

Model returns Model: 
	documents+=Document 
;
Document returns Document :
	ui=UI
;
UI returns UI: 
	...
;
....some more stuff

grammar de.xxx.tooling.DataDsl with org.eclipse.xtext.common.Terminals

import "http://www.xxx.de/tooling/model/DslEcore"
import "http://www.eclipse.org/emf/2002/Ecore" as ecore


DataRule returns Data: 
	("Fields" "{"
		(fields+=FieldRule)+
	"}")*
	(groups+=GroupRule)+
;


GroupRule returns Group:
	...skipped
;

FieldRule returns Field:
	...skipped...
;

grammar de.xxx.tooling.UiDsl with org.eclipse.xtext.common.Terminals

import "http://www.xxx.de/tooling/model/DslEcore"
import "http://www.eclipse.org/emf/2002/Ecore" as ecore


UIRegel returns UI:
	felder+=(FeldRefRegel)*
;

FieldRefRegel returns FieldRef:
	HorizontalFieldRule | VerticalFieldRule
;

HorizontalFieldRule returns HorizontalFieldRef:
	"horizontal" "(" horizontaleFields+=[Field] ")" 
; 

VerticalFieldRule returns VerticalFieldRef:
	"field" field=[Field] 
;

@Ecore(nsURI="http://www.xxx.de/tooling/model/DslEcore")
@GenModel(
	modelDirectory="/de.xxx.tooling/emf-gen", 
	modelName="DslEcore",
	forceOverwrite="true", 
	updateClasspath="false", 
	complianceLevel="8.0"
)
package de.sdvrz.tooling.model

// 
// Data
// 

class Data {
	derived String name get {
		//Paths.get(this.eResource.URI.toFileString).parent.fileName.toString
		this.eResource().getURI().segment(3)
	}
	contains Field [] fields
	contains Group [] groups
}


class Group {
	...skipped
}

class Feld {
	...skipped
}

//
// UI
//

class UI {
	derived String name get {
		//Paths.get(this.eResource.URI.toFileString).parent.fileName.toString
		this.eResource().getURI().segment(3)
	}
	contains FieldRef [] fields
}

interface FieldRef {

}

class VerticalFieldRef extends FieldRef{
	refers Field field
}

class HorizontalFieldRef extends FieldRef {
	refers Field[] horizontalFields
}

HorizontalFieldRule returns HorizontalFieldRef:
	"horizontal" "(" horizontalFields+=[Field] ")" 
; 

VerticaleFieldRule returns VerticalFieldRef:
	"field" field=[Field] 
;

field <fieldref_1>
horizontal (<fieldref_2> <fieldref_3>)
field <fieldref_4>
...

class MyDslRuntimeModule extends AbstractMyDslRuntimeModule {
	
	override bindIQualifiedNameProvider() {
		SimpleNameProvider
	}
	
}