 callback method receives a parameter <b>$line_of_tokens</b>, which is a reference to a hash of other useful information. This example uses these hash entries:</p>

<pre><code> $line_of_tokens-&gt;{_line_number} - the line number (1,2,...)
 $line_of_tokens-&gt;{_line_text}   - the text of the line
 $line_of_tokens-&gt;{_line_type}   - the type of the line, one of:

    SYSTEM         - system-specific code before hash-bang line
    CODE           - line of perl code (including comments)
    POD_START      -