private static Production[] createRules(Node node) {
		Map e2t = elementsToText(node);
		String left = (String) e2t.get(RULE_LEFT_NAME);
		if (left == null)
			left = "";
		NodeList list = ((Element) node).getElementsByTagName(RULE_RIGHT_NAME);
		Production[] p = new Production[list.getLength()];
		for (int i = 0; i < list.getLength(); i++) {
			String right = containedText(list.item(i));
			p[i] = new Production(left, right == null ? "" : right);
		}
		return p;
	}