I loathe perl still (based on having to SSH (or telnet?) into people's systems and debug their perl scripts in the 90s) but, Higher Order Perl, https://hop.perl

I loathe perl still (based on having to SSH (or telnet?) into people's systems and debug their perl scripts in the 90s) but, Higher Order Perl, https://hop.perl.plover.com/ https://hop.perl.plover.com/ is a truly excellent introduction to the power of functions that generate functions, more accessible and more immediately useful than Paul Graham's On Lisp. The lessons are immediately applicable at least to Javascript and Python. Strongly typed things like Go make it a bit more work, but still you'll understand why the work is worth doing.