live/examples/tree.emf - gerrit/www.eclipse.org/epsilon - Git at Google

 package tree;

 class Tree {
 	attr String label;
 	val Tree[*]#parent children;
 	ref Tree#children parent;
 }
	package tree;

	class Tree {
	attr String label;
	val Tree[*]#parent children;
	ref Tree#children parent;
	}