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I’m going to briefly tangent away from my usual HOWTO-style column, and get a
bit teary-eyed and philosophical. There’s been a lot of hype lately about PHP and Perl:
one columnist claims that PHP is killing Perl, another one claims that PHP is
overrated, and the newsgroups are filled with “PHP kicks Perl’s [butt]” and “Perl
dusts PHP” postings. Since both of these languages are so crucial to Web automation, I
thought I’d take article and help cut through the zeal and look at these
languages.
It’s turning out to be the eternal debate in the Apache world: which is better, PHP or Perl? Both, according to Matthew Keller, who makes some compelling arguments for both.
Just for the record, I’ve used Perl for many years and PHP for a little over
a full year. I’ve created large applications in Perl, and I’ve created
mediumishly-large applications in PHP. I know Perl like the back of my hand, but I also
know PHP pretty well. Nine times out of ten I’ll make a web application in
Perl instead of PHP, but that’s my choice, and the reasons for that will unfold
below.
PHP and Perl are both interpreted languages, which means they aren’t compiled
like C or Java. Instead of being compiled, they are read by an interpreter,
which instructs the computer to “Do the Right Thing” (patent pending). Both
languages can be embedded in HTML documents, and both languages have Apache
module-based interpreters available.
Perl
Perl is not only a Web-scripting language, and looking at is as such only
shows a microcosm of its true nature. Perl is, at its most basic level, a
text-manipulation language. It provides powerful features that allow the user to
easily do some operations that are very complex in C, and also complicates some
other things that are easy in C! Perl, in conjunction with CPAN (the Comprehensive Perl Archive Network)
offer an enormous amount of “ready-made” modules, that allow code to be reused
and shared- database interface modules, CORBA modules, scientific calculation
modules, network programming modules, SGML/XML/HTML modules, and so much more.
Obviously, because of Perl’s powerful and easy text manipulation functions, it
was quite natural for web developers to expand their toolbelt to include Perl.
Perl can be embedded within HTML documents, run as an SSI (Server-Side Include),
or run as its own application (CGI, or Common Gateway Interface). Perl, as
applied to CGI and web application design, is designed for the programmer who
wants to “output” webpages. A Perl Web application is nothing more or less than
a backend program, that interacts with the browser using HTML.
PHP
PHP is an embedded scripting language. A PHP-aware webserver parses HTML
documents looking for PHP code, processes it, and sends the results back to the
browser. PHP’s popularity lies in the fact that it is easy to use, and is
readily embeddable into HTML documents. Using PHP in conjunction with your
favorite HTML editor is an increasingly popular way to provide dynamic web
content, with minimal programming. In effect, PHP separates web design from
application design. I’ve worked on a couple large PHP projects where the HTML
designers were not even part of the application design team. PHP is developed
with the web, and web development in mind.
PHP and Perl: Their Similarities
These languages are both very similar in a lot of areas. Here are few of the
most crucial areas that these languages are similar, in my opinion.
Server-Side
Even though PHP or Perl code might be embedded in an HTML document, it is
processed by the server and not the client browser. The exception to this (other
than misconfigured servers!) is PerlScript, which I know absolutely nothing
about.
