 a string name and
    the second argument does not appear to be an LPeg pattern. Perhaps you
    expected something like:</p>

    <pre><code>
    local ws = token('whitespace', S('\t\v\f\n\r ')^1)
    </code></pre>

    <p>The <code>lexer</code> module actually provides a convenient list of common token names
    and common LPeg patterns for you to use. Token names include
    <a href="#lexer.DEFAULT"><code>lexer.DEFAULT</code></a>, <a href="#lexer.WHITESPACE"><code>lexer.WHITESPACE</code></a>, <a href="#