Well, it is as much of a Perl tutorial as Learn vi/vim in 50 lines and 15 minutes
or Using CVS for revision control
-- more so, in fact.
I realize that it is not a Perl tutorial, in the sense of its purpose being to teach nothing but the Perl language -- it's a tutorial on writing a parser and interpreter, using Perl.
But, as I said, I think that it is one of the few free online tutorials that I've found which shows how to use Perl to construct software on a larger scale than "Hello world", and "Create a class, instantiate object, call method, done". That
is why I think that it belongs in the Tutorials section.