The Perl-Journal Dezember 2002 #

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December 2002 
The Perl The Perl Journal Journal 
Creating RSS Files with XML::RSS 
Derek Vadala • 3 
Making a Cross-Platform Installer 
with Perl 
Max Schubert • 6 
Perl & Rapid Database Prototyping 
Tim Kientzle • 10 
Ruby vs. Perl 
brian d foy • 13 
Mining Mail 
Simon Cozens • 15 
PLUS 
Letter from the Editor • 1 
Perl News by Shannon Cochran • 2 
Book Review by Cameron Laird: 
Programming Perl in the .NET Environment • 19 
Source Code Appendix • 20
LETTER FROM THE EDITOR 
The Installer Question 
Writing Perl modules is easy, as witnessed by the nearly 4000
modules 
available on CPAN (the Comprehensive Perl Archive Network).
However, 
writing Perl apps that depend on multiple modules and that must 
be installed on multiple platforms is not so easy. Sure, Perl is a
platform-neutral 
language (mostly). And sure, we have a great resource in CPAN and
its CPAN module 
that, in theory at least, installs any module you need. 
But theory and practice quickly diverge when you try to distribute
a Perl app of 
any significant complexity to a varied group of users. Max
Schubert, whose article 
“Making a Cross-Platform Installer with Perl” appears on
page 6, can attest to 
this. The complexities of third-party module dependencies,
platform-specific Perl 
behavior, and even platform-specific module bugs all became
significant hurdles 
for him on the way to delivering an app. 
The reality for most complex Perl applications is that, unless the
app is distributed 
in multiple OS-specific forms, users need some sort of Perl
expertise to troubleshoot 
the installation. Perl’s open, extensible, modular form gives
you huge flexibility. I 
don’t know about you, but I love knowing that I don’t
have to reinvent many wheels 
in my Perl code. But the price we pay for this flexibility is
module-dependency 
complexity. This is why some people have argued that such
complexity holds Perl 
back from true success in the enterprise. 
Of course, there have been attempts to address this. James
Tillman’s PAIX project 
(http://www.sourceforge.net/projects/paix/), for instance, a is a
cross-platform installer 
designed to cope with the installation hassles he encountered in
his work on the Guido 
Tk app builder project
(http://www.sourceforge.net/projects/guido/). PAIX is a fine 
start, but what we really need is a seamless installation facility
built into Perl itself. 
There are some hints that Perl 6 may provide this. In a May 2002
posting on use Perl;, 
Larry Wall and Damien Conway were asked what modules were likely to
be included 
in the base Perl 6 distribution. Their response was tantalizing: 
It’s impractical to ship Perl 6 with a thousand modules, so
we’re seriously considering 
shipping it with almost none, and instead making the process of
downloading 
and installing appropriate SDKs highly safe and transparent. 
Since then, there doesn’t seem to have been a lot of
discussion about the issue, 
perhaps because it has gotten lost in larger issues. There are,
after all, other criticisms 
being laid on Perl’s doorstep—it’s not readable
enough, it’s too tightly coupled 
to UNIX, it’s too hard to integrate C/C++ libraries. All of
these problems limit 
Perl’s ability to scale, and all could potentially derail
Perl’s adoption. Some people 
say these issues already have hurt Perl, and that it is losing out
to languages like 
Python because of it. Whether this is true and whether the creators
of Perl 6 find a 
wise and practical solution to the installation question, we know
that they face a 
balancing act—making Perl scalable on one hand, while on the
other keeping the 
flexibility of the “more than one way to do it” approach
that has been such an integral 
part of Perl’s success. 
Kevin Carlson 
Executive Editor 
kcarlson@tpj.com 
Letters to the editor, article proposals and submissions, and
inquiries can be sent to 
editors@tpj.com, faxed to (650) 513-4618, or mailed to The Perl
Journal, 2800 Campus 
Drive, San Mateo, CA 94403. 
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1 The Perl Journal ? December 2002