public String[] getVariablesOnRHS() {
		ProductionChecker pc = new ProductionChecker();
		ArrayList list = new ArrayList();
		for (int i = 0; i < myRHS.length(); i++) {
			char c = myRHS.charAt(i);
			if (ProductionChecker.isVariable(c))
				list.add(myRHS.substring(i, i + 1));
		}
		return (String[]) list.toArray(new String[0]);
	}