this post was submitted on 10 Sep 2023
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hi, i was interested if perl is still relevant in this day and age. Perl has been on the decline for a very long time now. Perl 6 (now named 'raku) not being backwards compatible with perl 5 code made the already small perl community even smaller by splitting it in half. A good example is lisp with it's thousands of different dialects.

Is it still worth using or is it bound to legacy software forever? Like cobol.

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[–] Kazumara@feddit.de 4 points 1 year ago (3 children)

unexpected bits of flexibility

The worst one I stumbled across while reading a colleagues script was the three separate namespaces for symbols of type scalar, array, and hash.

[–] dan@lemm.ee 1 points 1 year ago* (last edited 1 year ago) (2 children)

You mean the fact that you can have a hash called %foo, an array called @foo and a scalar called $foo all at the same time? I agree that's a weird choice and there's potential for insanity there, but it's pretty easy to just not do that...

20+ years of Perl experience and while Perl has a load of idiosyncrasies that make it harder to work with than other languages, I don't think that particular one has ever caused a significant problem.

[–] Kazumara@feddit.de 1 points 1 year ago* (last edited 1 year ago) (1 children)

You mean the fact that you can have a hash called %foo, an array called @foo and a scalar called $foo all at the same time?

Yes, exactly. Those definitions aren't clashing, so they must have separate namespaces.

it’s pretty easy to just not do that…

I wouldn't do that either, but my colleage apparently did. So far I'm having a harder time reading perl than writing it.

[–] dan@lemm.ee 1 points 1 year ago

The way it works is that there's a symbol table entry for "foo" which has a slot for a hash, scalar, array, glob, etc.

That leads to some super weird behaviour like, for example, if I declare a scalar, hash and array as "x":

$x = "sy";
%x = (foo => "mb");
@x = ("ol", "s!");

You can access them all independently as you're aware:

say "x: ", $x, $x{foo}, @x; # Outputs:  x: symbols!

But what's really going to bake your noodle is I can assign the "x" symbol to something else like this:

*z = *x;

..and then the same thing works with z:

say "z: ", $z, $z{foo}, @z; # Outputs:  z: symbols!

Oneliner if you want to try it:

perl -E '$x = "sy"; %x = (foo => "mb"); @x = ("ol", "s!"); say "x: ", $x, $x{foo}, @x; *z = *x; say "z: ", $z, $z{foo}, @z;'

Congratulations! You now know more about one of Perl's really weird internals than I'd wager most Perl programmers (I have literally never used any of the above for anything actually productive!)