Perl is still a great choice


Published by Paul at 2022-05-27, Comic source: XKCD

Perl (the Practical Extraction and Report Language) is a battle-tested, mature, multi-paradigm dynamic programming language. Note that it's not called PERL, neither P.E.R.L. nor Pearl. "Perl" is the name of the language and "perl" the name of the interpreter or the interpreter command.

Unfortunately (it makes me sad), Perl's popularity has been declining over the last years as Google trends shows:


So why is that? Once the de-facto standard super-glue language for the web nowadays seems to have a bad repetition. Often, people state:

Write-only language

Is Perl really a write-only language? You have to understand that Perl 5 was released in 1994 (28 years ago as of this writing) and when we refer to Perl we usually mean Perl 5. That's many years, and there are many old scripts not following the modern Perl best practices (as they didn't exist yet). So yes, legacy scripts may be difficult to read. Japanese may be difficult to read too if you don't know Japanese, though.

To come back to the question: Is Perl a write-only language? I don't think so. Like in any other language, you have to apply best practices in order to keep your code maintainable. Some other programming languages enforce best practices, but that makes these languages less expressive. Perl follows the principles "there is more than one way to do it" (aka TIMTOWDI) and "making easy things easy and hard things possible".

Perl gives the programmer more flexibility in how to do things, and this results in a stronger learning curve than for lesser expressive languages like for example Go or Python. But, like in everything in life, common sense has to be applied. You should not take TIMTOWDI to the extreme in a production piece of code. In my personal opinion, it is also more satisfying to program in an expressive language.

Some good books on "good" Perl I can recommend are:

Modern Perl
Higher Order Perl

Due to Perl's expressiveness you will find a lot of obscure code in the interweb in form of obfuscation, fancy email signatures (JAPHs), art, polyglots and even poetry in Perl syntax. But that's not what you will find in production code. That's only people having fun with the language which is different to "getting things done". The expressiveness is a bonus. It makes the Perl programmers love Perl.

JAPH
http://www.cpan.org/misc/japh
Perl Poetry

Even I personally have written some poetry in Perl and experimented with a polyglot script:

My very own Perl Poetry
A Perl-Raku-C polyglot generating the Fibonacci sequence

This all doesn't mean that you can't "get things done" with Perl. Quite the opposite is the case. Perl is a very pragmatic programming language and is suitable very well for rapid prototyping and any kind of small to medium-sized scripts and programs. You can write large enterprise scale application in Perl too, but that wasn't the original intend of why Perl was invented (more on that later).

Is Perl abandoned?

As I pointed out in the previous section, Perl 5 is around for quite some time without any new major version released. This can lead to the impression that development is not progressing and that the project is abandoned. Nothing can be further from the truth. Perl 5.000 was released in 1994 and the latest version (as of this writing) Perl 5.34.1 was released two months ago in 2022. You can check the version history on Wikipedia. You will notice releases being made regularly:

Perl 5 version history

As you can see, Perl 5 is under active development. Actually, Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was officially changed to Raku in October 2019 as the differences between Perl 5 and Perl 6 were too groundbreaking. Raku would be a different topic (mostly out of scope of this blog article) but I at least wanted it to mention here. In my opinion, Raku is the "most powerful" programming language out there (I recently started learning it and intend to use it for some of my future personal programming projects):

The Raku Programming Language

So it means that Perl and Raku now exist in parallel. They influence each other, but are different programming languages now. So why not just all use Raku instead of Perl? There are still a couple of reasons of why to choose Perl over Raku:

Perl feature pragmas
The OpenBSD Operating System
Why does OpenBSD still include Perl in its base installation?

The renaming of Perl 6 to Raku has now opened the door for a future Perl 7. As far as I understand, Perl 7 will be Perl 5 but with modern features enabled by default (e.g. pragmas "use strict; use warnings; use signatures;" and so on. Also, the hope is that a Perl 7 with modern standards will attract more beginners. There aren't many Perl jobs out there nowadays. That's mostly due to Perl's bad (bad for no real reasons) repetition.

Announcing Perl 7
What happened to Perl 7? (maybe have to use "use v7;")

Why use Perl as there are better alternatives?

Here, common sense must be applied. I don't believe there is anything like "the perfect" programming language. Everyone has got his preferred (or a set of preferred) programming language to chose from. All programming languages come with their own set of strengths and weaknesses. These are the strengths making Perl shine, and you (technically) don't need to bother to look for "better" alternatives:

About the first point, using Perl for better "shell" scripts was actually the original intend of why Perl was invented in the first place.

Perl one-liners
Mastering Regular Expressions
Taint checking

Here are some reasons why not to chose Perl and look for "better" alternatives:

Cor - A minimal object system for the Perl core - proposal

Why all the sigils? It looks like an exploding ASCII factory!!

The sigils $ @ % & (where Perl is famously known for) serve a purpose. They seem confusing at first, but they actually make the code better readable. $scalar is a scalar variable (holding a single value), @array is an array (holding a list of values), %hash holds a list of key-value pairs and &sub is for subroutines. A given variable $ref can also hold reference to something. @$arrayref dereferences a reference to an array, %$hashref to a hash, $$scalarref to a scalar, &$subref dereferences a referene to a subroutine, etc. That can be encapsulated as deep as you want. (This paragraph only scratched the surface here of what Perl can do, and there is a lot of syntactic sugar not mentioned here).

In most other programming languages, you won't know instantly what's the "basic type" of a given variable without looking at the variable declaration or the variable name (If named intelligently, e.g. a variable name containing a list of socks is "sock_list"). Even Ruby makes some use of sigils (@ @@ an $), but that's for a different purpose than in Perl (in Ruby it is about object scope, class scope and global scope). Raku uses all the sigils Perl uses plus an additional bunch of twigils, e.g. $.foo for a scalar object variable with public accessors, $!foo for a private scalar object variable, @.foo, @!foo, %.foo, %!foo and so on. Sigils (and twigils) are very convenient once you get used to them. Don't let them scare you off - they are there to help you!

https://www.perl.com/article/on-sigils/

Where do I personally still use perl?

Btw.: Did you know that the first version of PHP was a set of Perl snippets? Only later, PHP became an independent programming language.

https://www.perl.org

E-Mail me your comments to paul at buetow dot org!

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