C =			"c" <a> A extends A.

A :			B
			| C			.

B =			"b" extends A.

Main =			<s> String.

notparsed visitor PrintVisitor =			<indent> int <needSpace> boolean extends UniversalVisitor.

notparsed visitor CopyVisitor =			<copy> derived Object extends UniversalVisitor.

notparsed visitor SubgraphVisitor =			<is_equal> boolean init {{ true }} extends UniversalVisitor.

notparsed visitor EqualVisitor =			<is_equal> boolean init {{ true }} extends UniversalVisitor.

notparsed visitor DisplayVisitor =			<indent> int extends UniversalVisitor.

notparsed visitor TraceVisitor =			<indent> int extends UniversalVisitor.

notparsed visitor UniversalVisitor :						.