 <code>lexer.ERROR</code> token.</p>

    <p>Even though the rules defined in the examples above contain a single token,
    rules may consist of multiple tokens. For example, a rule for an HTML tag
    could consist of a tag token followed by an arbitrary number of attribute
    tokens, allowing the lexer to highlight all tokens separately. That rule
    might look something like this:</p>

    <pre><code>
    lex:add_rule('tag', tag_start * (ws * attributes)^0 * tag_end^-1)
    </code></pre>

    <p>Note 