public void implementInterface(OutputModelObject value) {
		if (interfaces == null) {
			interfaces = new ArrayList<OutputModelObject>();
		}

		interfaces.add(value);
	}
This object models the structure holding all of the parameters,
 return values, local variables, and labels associated with a rule.
tool/src/org/antlr/v4/codegen/model/decl/StructDecl.java