[creer]

What exactly is complex or "super subtle" about this? It's the textbook example from the 1st chapter in the tutorial or something?

[atherton94027]

It's just very non-obvious what the code does when you're skimming it.

Especially in a dynamic language like Perl, you wouldn't know that you're passing down an integer instead of a function until the code blows up in a completely unrelated function.

[weare138]

Then use one of the type systems for Perl.

https://metacpan.org/pod/Type::Tiny