Some of it I recognize as being an artefact of the time, when conciseness really mattered. But it's still obnoxious in 2025.
The whole thing reminds me of D&D, which is full of classes & spells that only exist in modern D&D because of One Guy who happened to be at the table with Gygax, who really wanted to be a wuxia guy he saw in a movie, or because he really wanted a spell to be applicable for that one night at the table, and now it's hard-coded into the game.
Yes, one can write obscure perl code and some love perl golfing. In the same way there is an IOCCC which delights in unreadable code, it doesn't mean that the C language should be relegated to the dustbin. The answer is to write readable code, no matter which language is in use.
- Why is there a `1;` on a single line in the middle of this file?
- What is `$_`?
- This parallel execution manager doesn't actually seem to define what code needs to run in parallel in any specific way, how does this work?
- What is this BEGIN block at the start of this Perl file? Why is that necessary?
- What's going on with qx, qw, qq?
- What does chomp do when it's just on its own line, with no arguments given to it?
$_ is inscrutable if you haven't studied perl, but the same thing would happen to anyone who sees a python decorator for the first time. what does "else: do after a while loop in python? Only people who know python know what it does (and I suspect most don't). The different quoting operators are also trivial to learn. In comparison, yield from python is also simple syntax but the semantics are much more involved.
BEGIN? Take 60 seconds to read what it means. And if you knew awk, you'd not have to do that, as it was directly lifted from awk.
Yes, that's exactly the problem: it's additional mental load you have to read up on.
Have 60 of those small oddities in a file, and suddenly you're spending an hour dealing with Perl quirks rather than actually debugging that obscure script a retired coworker wrote a decade ago. A 5-minute fix turned into a 65-minute fix, solely because of Perl.
Most programming languages use more-or-less the same constructs, and the few per-language oddities are usually fairly obvious from context. In practice this means someone familiar with any programming language will to a certain extent be able to read, debug, and patch small issues in code written in any other programming language. Perl's obscure and dense syntax makes this virtually impossible. Give a buggy Python script to a developer who daily-drives Javascript and they can probably fix it. Give a buggy Perl script to that same Javascript developer, and they probably have absolutely no clue what's going on.
In practice this turns Perl into technical debt. It has very few natural niches where it is genuinely the best, so experienced Perl developers are quite rare to have around. Any script written in Perl will most likely have to be read by someone who isn't an experienced Perl developer - which is significantly harder than a script written in just about any other language. The result is that any Perl scripts you have lying around are basically a grenade waiting to go off: they can't be maintained, so they should probably be replaced.