public ParseTreeNode excludeSetTail() throws SyntaxError {
		ParseTreeNode node = new ParseTreeNode("<exclude-set-tail>");
		if (accept('[')) {
			node.addChild("[");
			node.addChild(charSet());
			if (accept(']')) {
				node.addChild("]");
			}
			return node;
		} else if (isDefinedClass()) {
			node.addChild(String.valueOf(symbol));
			accept(symbol);
			return node;
		} else {
			throw new SyntaxError("Invalid excludeSetTail");
		}
	}