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Comment by benbristow | Hacker News Reader

I used to work for a company that used Perl as their primary language.

The codebase was millions of lines long, modules (pm files) with like 1000 methods and 10,000 lines, a total mess and it had 0 unit tests too. Almost beyond salvageable. Left a bit of a sour taste.

They're trying to migrate to AWS but AWS don't even natively support Perl in their libraries. There's a few third party libraries in CPAN but nothing as comprehensive as what's available with official libraries for other languages.

Nothing against the language but I don't know why you wouldn't use literally anything else nowadays. Python or PHP, JavaScript or even Ruby if you're looking for a dynamically typed language. AWS don't even support Perl.

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Perl used to have one of the most extensive module libraries. One of the things I miss about Perl was it’s more sensible module namespace convention (Eg Net::... for networking related) vs the more hip but confusing and hard to discover naming of node modules.

Yes, the hierarchical namespace for modules was super nice. Migrating to a flattened package structure of npm was a disappointment. I ended up encoding the same type of structure in internal npm package names, e.g. "@myorg/net-aws-.." and "@myorg/file-..."

Keep in mind TDD wasn't really invented yet, so it's understandable.

Also, CPAN had better libraries than pip did all the way up until I last used Perl in 2015. Ofc, it depends on what you're doing. My point is, there was a reason to use Perl once upon a time ago.

The alternatives back then were PHP, C, C++ (the old bad kind), BASIC, assembly, FORTRAN, and others like Smalltalk. Seeing this, it's understandable why Java took the world by storm the same way Perl did.

I don't know about TDD specifically but we have the Perl community to thank for setting the bar for rigorous testing back in the ealry 2000s with the numerous Test:: modules on CPAN.

Perl and CPAN definitely do not get enough flowers for their contribution to TDD.

Last Perl shop I worked at was newer than the company you described but well on its way toward being like this.

Since Perl code is often very compact, it probably needs a higher comment to code ratio than most other languages, but you don't see that either.

Your opinion on Perl is based on one code base you worked at on one job?

Honestly that's more than most I think. I've written tens of thousands of lines of perl professionally and I generally share the same opinion.

I've been writing (Modern) Perl for about 3.5 years and I disagree that Perl necessarily tends to unreadable code. I really don't think that's true at all.

To quote myself from a recent discussion:

I think some languages do make it easy to write convoluted code, but through judicious use of coding standards (including a helping of common sense [don't be clever where you can at all avoid it, which IME is ~~almost~~ all the time], code linters, and so on) I think how you use a language plays a huge part in code maintainability.

For instance, I've heard PHP get shit on pretty badly all around the web, but I've worked at PHP shops that had nice, clean codebases, and my current Perl codebase is, in many ways, nicely structured. That's not to say there aren't some hairy codepaths that could use refactoring, but I really think that kind of thing, again, can happen in almost any language.

Strongly agreed. It’s much more about the team, the conventions used, the organization of the codebase, and the coding culture of the team, than it is about a specific language.

True, but the cultures that grow up around a specific language tend to encourage certain conventions, standards of organization, and team coding cultures.

Under that standard it’s true, but it’s also true for virtually any language and is therefore not a good defense of whether or not a language lends itself to unreadable code.

There are a couple of points in there:

1. You can use virtually any language to write clean code

Not sure if I agree with this, though it may well be true. I just know there are some things like Brainfuck where it's designed to be impossible. I realize that language is created specifically for the purpose of making a coder say "WTF", but perhaps there are other languages that are not designed to be so that are really nearly impossible to write good code in.

2. Perl lends itself to unreadable code

If you stick to Modern Perl you still might end up with things like `wantarray` in your code so I guess this is kind of true. You need to be judicious in your use of code.

Some languages lend themselves more easily to writing clean code, like I feel about Go or if you hate the Go type system, Ruby. Even in Ruby I feel like metaprogramming is ripe for misuse.

It's a tough thing to talk about. I don't feel like I wholeheartedly disagree with your sentiment which seems to be "some languages lend themselves to bad code" and subsequently that Perl lends itself to bad code but there is plenty of ambiguity in these thoughts.

In my 30 years (yes) working with Perl (4->5.32), I have never, once, used wantarray. Perl does not lend itself to bad code. Bad coders, people whom cannot use or articulate good practice in coding or documentation, lend themselves to write bad code, in any language.

I used it for automation of my calculations in grad school. For data analysis. For monitoring.

In my subsequent day jobs, I used it to develop shipping products. No one really should care what language something is written in, if it does the job well.

Most recently (a few weeks ago), I used it as the driver for creating and submitted 10's of thousands of jobs for COVID19 research the team I am working with[1][2].

For the above project, I had to forward port 12 year old C++ code to make use of modern C++ based boost libraries. Took a bit of time to fix this. But the perl code, ran perfectly, and quickly[3].

Anyone trying to portray things otherwise, likely has a longstanding axe they like to grind. Language advocacy can be done without attempting to tear down other languages. Though those who argue against perl often bring up the same, old, tired, and incorrect points.

I'll keep using perl thank you. And Julia. And C. Each has their domain of applicability. Most people know and understand this.

[1] https://community.hpe.com/t5/advantage-ex/how-my-supercomput...

[2] https://community.hpe.com/t5/advantage-ex/the-story-of-how-i...

[3] https://scalability.org/2020/04/fun-and-topical-hpc-project-...

I think a useful concept is that a project will have a "discipline budget", just like the "language strangeness budget". Yes, if you're careful with your self-restraint and code reviews, you can write good, clean, maintainable code in a language that doesn't give you a lot of support for that. But if you do that then you're expending your limited supply of discipline, and will have less to spend on other aspects of the project like not scaling prematurely, not using cool-but-unnecessary tech...

Very interesting thought! I think I'll steal it.

Yeah, I've got a Perl codebase that's conservatively tens of thousands of lines, and it's honestly a struggle to write anything in it that isn't a big ball of mud. There's about 50 different ways to do anything in the language, the syntax is infuriatingly obtuse, and you can't rely on any documentation because it will recommend doing things that experts don't recommend doing.

The system is from like 2013 and still going, but I really wish I could rewrite it in a language I can actually train people on in a reasonable amount of time. It took the one junior I have about 6 months to get to the point where he could read the syntax without tearing his hair out. It's not really built to create maintainable structures.

The libraries and stuff are full of opinionated little "gotchas." As an example, the Test::Simple module will throw errors if you use a number to title a test which is infuriating when you're writing a test which tests all the numbers in the space of acceptable or possible inputs.

Perl's syntax is really confusing.

Especially for example how variables have symbols for different types ($ for scalars, % for hashes, @ for arrays). And if you want to for example pass an array to a function you have to send it manually referenced with like method(\@myArray) which then inside the method is contained in a $scalar.

Compared to Python for example where you'd literally just pass the array to the method like method(array).

> Compared to Python for example where you'd literally just pass the array to the method like method(array).

How does one tell Python to pass the contents of said array as distinct parameters to the function, instead of as a lone array parameter?

In Perl, that's the difference between foo(@bar) and foo(\@bar) or foo(1, 2, 3) vs foo([1, 2, 3]).

> How does one tell Python to pass the contents of said array as distinct parameters to the function, instead of as a lone array parameter?

With an asterisk: method(*array)

Right, which I sorta kinda get why coming from C - a *something is the thing pointed to by that something.

How is that more understandable than @ vs \@ without knowing the language? My guess is it isn't.

As someone who learned python first - the idea that `myfn(@xs)` would call `myfn(1,2,3)` is... unnerving. Implicitly splicing in arguments makes me wonder what other kind of syntactic oddities are going over my head in my code.

Python is "relatively" consistent about * and being used to expand or contract arrays and dicts, respectively.

   a, *, b = [1,2,3,4]
   def foo(*args):
   bar(*[1,2,3])

all do "what you'd expect" from the single concept that "* is sort of pattern-matchy for an array".

But the more important bit is just that you don't have to prefix variables with @ and $. Python is optimized for writing code that acts on variables, while perl is optimized for code that acts on strings. While strings are certainly a common data type, most code isn't modifying strings directly. So optimizing for that case doesn't make a lot of sense.

a = [1]

def f(b):

   print(b)

f(a)

f(*a)

For many years Perl subroutines didn't even have method signatures so you had to unroll @ on the first line of every sub. I think even today it may still be considered experimental. Jeez!

Yeah it's pretty archaic. Shortest hand way of doing it is like this:

  sub method {
    my ($self, $a, $b, $c) = @_;
  }

$self being a reference to the current module (ala Javascript's 'this')

$self is only for OOP so not needed in a regular subroutine.

The reason for the @_ is that it is a simple way to get both pass by value and pass by reference semantics.

The values in @_ are aliased to the values in the subroutine call.

Most of the time, you want pass by value semantics, so you unpack the array and copy the values into function variables. If you want to modify an argument, it's typically passed in as a reference, and you can mess with it that way.

However, there are times when it would be horribly inefficient to make those copies, or when you need to do some magic (generally best avoided in 99.999% of your code), that this makes possible.

Also, since Perl functions are always variadic, it means that it's easy to work with a variable list of arguments in a function. For example, if you are expecting a list of key value pairs for your function, you can simply write:

  my %args = @_

Making signatures default will be a big improvement, but the power of the simple abstraction @_ provides should not be underestimated. It's actually an elegant solution to a complex problem.

I can say the same thing about a legacy Java codebase that I had to work with at a big "enterprise" software company a few years ago. The code was so convoluted, with some files over 12k lines long. You can write spaghetti code in any language.

How much and what kind of experience do you think someone should have with a language before beginning to form an opinion?

They mention aws library support as another major concern too.

> There's a few third party libraries in CPAN but nothing as comprehensive as what's available with official libraries for other languages.

That is true. This alone might be a good reason to look elsewhere for new projects.

However, for existing Perl codebases, PAWS is comprehensive and popular library, and is generated from the official botocore: https://github.com/pplu/aws-sdk-perl

> There's a few third party libraries in CPAN but nothing as comprehensive

There's 194,000 modules, which is probably the most of any language:

https://www.cpan.org/

> Nothing against the language but I don't know why you wouldn't use literally anything else nowadays.

Gee, let me see:

- Perl's Mojolicious web framework is probably the most powerful today.

https://mojolicious.org/

- Perl has moderate static typing with use strict;

- Perl allows forward references, unlike Javascript or Python.

The question is why would I use anything but Perl?

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