I don't consider these as being particularly interesting differences. With the right modules, I can write code that looks like that in Perl. (It's not idiomatic, though, so it is worth exploring other languages to see which idioms you'd like to steal. I stole monads and applicative functors from Haskell for Perl in MooseX::Data, for example. Monadic control flow is not a common Perl idiom, but it is perfect for my asynchronous CPAN client.)

I am talking major differences, things that are so fundamental that you can't really steal. Looking at Haskell, I see things like lazy evaluation, purity, static typing and type inference, etc. Very, very different from Perl.

In Scheme, I see the "call stack" as a graph of frames, not as a linked-list as in C. This is quite radical.

But in Ruby and Python all I see are different built-in functions, some with special syntax. (Generators, list comprehensions, etc., etc.)

I know Perl far, far better than I know Ruby or Python. But I can't easily reach for the abstractions in those examples within Perl.

I can. I hope you are considering CPAN as part of Perl, because "core perl" is a very, very outdated and broken programming language. I think I would even prefer Java!