aspect ModuleExpr {
	public ModuleCompilationUnit ModuleExpr.getModuleInstance(ModuleCompilationUnit context) {
		throw new Error("getModuleInstance called on abstract ModuleExpr");
	}
	public ModuleCompilationUnit ModuleAccessExpr.getModuleInstance(ModuleCompilationUnit context) {
		return context.lookupModule(getModuleAccess().getID());
	}
	public ModuleCompilationUnit ModuleOwnExpr.getModuleInstance(ModuleCompilationUnit context) {
		ModuleCompilationUnit baseCU = getHostProgram().lookupModuleCUNoTransform(getModuleAccess());
		if (baseCU == null) {
			return null;
		}
		
		ModuleCompilationUnit instance = baseCU.generateModuleInstance(context, context.createAnonName(context)); 
		getHostProgram().getCompilationUnitList().addChild(instance);
		
		//remove context from the instance, the context will be added later on the replaces
		instance.removeInstanceContext(context);
		 
		return instance;
	}
	public ModuleCompilationUnit ModuleSingletonAccessExpr.getModuleInstance(ModuleCompilationUnit context) {
		ModuleCompilationUnit baseCU = getHostProgram().lookupModuleCUNoTransform(getModuleAccess());
		if (baseCU == null) {
			return null;
		}
		
		return baseCU.generateModuleInstance(null);
	}
}