I don't understand. Where is this code?

What more do you need other than <programlisting>?

This is what I mean, to have this kind of listing within programlisting:

<emphasis>#!/usr/bin/perl</emphasis>
<function>print</function> "A estas horas, el Estudiante, no creyendo 
+su buen suceso y
deshollinando con el vestido y los ojos el zaquizamí...\n"; 
<function>sleep</function> <constant">10</constant>;
[download]

I'm not aware of docbook filters doing that kind of stuff automatically, that's why I've hacked that script. The question is, is there any other (better) way of doing it?