alt Hacker NewsI think Perl died from a combination of three factors:
1. The rise of other web languages that did what Perl was good at but better.
Perl was probably a fine language for sysadmins doing some text munging. Then it became one of the first languages of the web thanks to Apache and mod_perl, but it was arguably never great at that. Once PHP, Python, Ruby, and (eventually) JavaScript showed up, Perl's significant deficiencies for large maintainable codebases made it very hard to compete.
In many cases, a new, better language can't outcompete an old entrenched one. The old language has an ecosystem and users really don't like rewriting programs, so that gives it a significant competitive advantage.
But during the early rise of the web, there was so much new code being written that that advantage evoporated. During the dot com boom, there were thousands of startups and millions of lines of brand new code being written. In that rare greenfield environment, newer languages had a more even playing field.
2. Perl 6 leaving its users behind.
As a language maintainer, I feel in my bones how intense the desire is to break with the past and Do Things Right This Time. And I'm maintaining a language (Dart) that is relatively new and wart-free compared to Perl. So I can't entirely blame Wall for treating Perl 6 as a blank check to try out every new idea under the sun.
But the problem is that the more changes you make to the language, the farther you pull away from your users and their programs. If they can't stay with you, you both die. They lose an active maintainer for the core tools they rely on. And you lose all of their labor building and maintaining the ecosystem of packages everyone relies on.
A racecar might go a lot faster if it jettisons all the weight of its fuel tank, but it's not going to faster for long.
I think the Perl 6 / Raku folks go so excited to make a new language that they forgot to bring their users with them. They ran ahead and left them behind.
3. A wildly dynamic language.
If you want to evolve a language and keep the ecosystem with you while you do it, then all of that code needs to be constantly migrated to the new language's syntax and semantics. Hand-migrating is nightmarishly costly. Look at Python 3.
It's much more tractable if you can do most of that migration automatically using tools. In order to do that, the tools need to be able to reason in detail about the semantics of a program just using static analysis. You can't rely on dynamic analysis (i.e. running the code and seeing what it does) because it's just not thorough enough to be safe to rely on for large-scale changes to source code.
Obviously, static types help a lot there. Perl 5 not only doesn't have those, but you can't even parse a Perl program without running Perl code. It is a fiendishly hard language to statically analyze and understand the semantics of.
So even if the Perl 6 folks wanted to bring the Perl 5 ecosystem with them, doing so would have been extremely challenging.
I would say this is a case study in a programming language tragedy, but I honestly don't even know if it's a bad thing. It may be that programming languages should have a life cycle that ends in them eventually being replaced entirely by different languages. Perhaps Perl's time had simply come.
I am grateful for all of the innovative work folks have done on Perl 6 and Raku. It's a cornucopia of interesting programming language ideas that other languages will be nibbling on for decades.
Replies
> But the problem is that the more changes you make to the language, the farther you pull away from your users and their programs. If they can't stay with you, you both die.
Should people just not make new languages any more?
Should new languages not bear deep resemblances to existing ones?
> Hand-migrating is nightmarishly costly. Look at Python 3.
> It's much more tractable if you can do most of that migration automatically using tools.
There was and is in fact abundant tool support for this in Python. The `2to3` script shipped with Python and the corresponding `lib2to3` was part of the standard library through 3.11. The third-party `six` compatibility libraries are still downloaded from PyPI more often than NumPy.
> In order to do that, the tools need to be able to reason in detail about the semantics of a program just using static analysis.
The experience of these tools users disagrees, from what I've seen. They produce ugly code in places, but it generally passes the tests. Yes, manual fixes are often necessary, but there were source packages published in that era (and it's not like they disappeared from PyPI either) that would detect the Python version in `setup.py`, run the tool if necessary at installation time, and have happy users.
Python's soul is "Pythonic", which stayed pure from Python 2 to Python 3, but Perl's soul was "Pearl-ick", and Perl 6 had a totally different kind of "ick" than Perl 5 did.
Perl's language design fetishizes solving self-inflicted puzzle after puzzle after puzzle.
https://www.artima.com/weblogs/viewpost.jsp?thread=147358
Language Design Is Not Just Solving Puzzles
by Guido van Rossum, February 10, 2006
Summary: An incident on python-dev today made me appreciate (again) that there's more to language design than puzzle-solving. A ramble on the nature of Pythonicity, culminating in a comparison of language design to user interface design.
Some people seem to think that language design is just like solving a puzzle. Given a set of requirements they systematically search the solution space for a match, and when they find one, they claim to have the perfect language feature, as if they've solved a Sudoku puzzle. For example, today someone claimed to have solved the problem of the multi-statement lambda.
But such solutions often lack "Pythonicity" -- that elusive trait of a good Python feature. It's impossible to express Pythonicity as a hard constraint. Even the Zen of Python doesn't translate into a simple test of Pythonicity.
In the example above, it's easy to find the Achilles heel of the proposed solution: the double colon, while indeed syntactically unambiguous (one of the "puzzle constraints"), is completely arbitrary and doesn't resemble anything else in Python. A double colon occurs in one other place, but there it's part of the slice syntax, where a[::] is simply a degenerate case of the extended slice notation a[start:stop:step] with start, stop and step all omitted. But that's not analogous at all to the proposal's lambda <args>::<suite>. There's also no analogy to the use of :: in other languages -- in C++ (and Perl) it's a scoping operator.
And still that's not why I rejected this proposal. If the double colon is unpythonic, perhaps a solution could be found that uses a single colon and is still backwards compatible (the other big constraint looming big for Pythonic Puzzle solvers). I actually have one in mind: if there's text after the colon, it's a backwards-compatible expression lambda; if there's a newline, it's a multi-line lambda; the rest of the proposal can remain unchanged. Presto, QED, voila, etcetera.
But I'm rejecting that too, because in the end (and this is where I admit to unintentionally misleading the submitter) I find any solution unacceptable that embeds an indentation-based block in the middle of an expression. Since I find alternative syntax for statement grouping (e.g. braces or begin/end keywords) equally unacceptable, this pretty much makes a multi-line lambda an unsolvable puzzle.
And I like it that way! In a sense, the reason I went to considerable length describing the problems of embedding an indented block in an expression (thereby accidentally laying the bait) was that I wanted to convey the sense that the problem was unsolvable. I should have known my geek audience better and expected someone to solve it. :-)
The unspoken, right brain constraint here is that the complexity introduced by a solution to a design problem must be somehow proportional to the problem's importance. In my mind, the inability of lambda to contain a print statement or a while-loop etc. is only a minor flaw; after all instead of a lambda you can just use a named function nested in the current scope.
But the complexity of any proposed solution for this puzzle is immense, to me: it requires the parser (or more precisely, the lexer) to be able to switch back and forth between indent-sensitive and indent-insensitive modes, keeping a stack of previous modes and indentation level. Technically that can all be solved (there's already a stack of indentation levels that could be generalized). But none of that takes away my gut feeling that it is all an elaborate Rube Goldberg contraption.
Mathematicians don't mind these -- a proof is a proof is a proof, no matter whether it contains 2 or 2000 steps, or requires an infinite-dimensional space to prove something about integers. Sometimes, the software equivalent is acceptable as well, based on the theory that the end justifies the means. Some of Google's amazing accomplishments have this nature inside, even though we do our very best to make it appear simple.
And there's the rub: there's no way to make a Rube Goldberg language feature appear simple. Features of a programming language, whether syntactic or semantic, are all part of the language's user interface. And a user interface can handle only so much complexity or it becomes unusable. This is also the reason why Python will never have continuations, and even why I'm uninterested in optimizing tail recursion. But that's for another installment.
Re #1:
Perl did not only have mod_perl. It also had the same kind of frameworks that made Ruby and Python great for web development. It was called Catalyst and was production ready around the same time as RoR and Django.
The real reason why perl failed on this front, IMHO, is that the language makes it super unergonomical to define any nested data structures. In Javascript, Ruby and Python, a list of dictionaries is just some JSON-like syntax: { "x": [...], "y": [...] }
In perl you have to deal with scalars, references, references to scalar, value references, ... and you have the sigils that mean different things depending on what the variable contains. I mean, I spent significant time writing perl and never figured this out.
In a world where you just want a CRUD to load/save a piece of structured data, the ones that let you operate on the data and keep your sanity wins.