Hi! I'm the floppy-haired guy in the interview. If you have any questions, please launch them at me via your comment boxes.
You have high fidelity repls for python and ruby. The Perl hi fi repl is called Reply (https://metacpan.org/pod/Reply). If you are interested check out the plugins -- especially for Term::ReadLine::Gnu. If you have questions, let me know.
Most languages probably don't have the ability to download dependencies from the internet on the fly. That might be a nice feature to have.