Ask HN: What new skills are you learning?

I'm trying to finally give Erlang, Scheme / Racket, and JavaScript the attention they deserve in my life.

I've been really enjoying Elixir – I always liked the idea of Erlang, but became frustrated in practice, and Elixir feels like it has been designed around my frustrations.

"Hacking", which has led me to start learning more about C, Assembly, and Networks.

I've been learning Haskell for the last year and a half, though I've been working with functionally inspired languages for 8 years. Haskell is wonderful, easily the most fun I've had learning a language in 20 years.

I'd advise not getting distracted by monads and other glamorous parts of the language. Monads are pretty abstract, and they won't likely make much sense until you've written enough Haskell to feel the pain-points they address.

I've learned a lot by reading blog posts from these people:

* Aditya Bhargava: http://adit.io

* Gabriel Gonzalez: http://www.haskellforall.com/

* Joseph Abrahamson: http://jspha.com/

* kqr (I don't know this person's full name. Avatar not withstanding, I'm pretty sure kqr isn't David Bowie): https://github.com/kqr/gists

* Edward Kmett: https://www.fpcomplete.com/user/edwardk

Most of all, I advise not getting discouraged. Haskell has a lot of concepts that seem intimidating. Many times I've spent days trying to figure out what the hell a contravariant functor is, only to get really discouraged. At times I've doubted my own abilities and whether learning the language was worth it. I stuck to it, and a year and a half later I'm pretty damn capable with Haskell (and I know what a contravariant functor is!) and I'm having the time of my life learning more about it.

I hope this isn't flippant, but have you read the Perl regex man pages [0]? "Perl compatible" regexes are very common, and are explained _really_ well. Similarly, the Perl Cookbook (from O'Reilly) has a whole chapter on regular expressions -- even crazy ones like detecting US phone numbers (hard!) -- with explanations. That chapter is QUITE good, and I highly recommend it even you don't write Perl.

For your specific problem at hand, I assume you want to replace spaces with a tab character.

In Perl, you could do:

  # replace four spaces with a tab, globally
  $line =~ s/    /\t/g;

You can do this directly on the command line as well:

  perl -e 'while () { $line = $_; $line =~ s/    /\t/g; print $line; }'  foo_tabs.py

I have a gist [1] which has very slightly more comments, if you prefer. To paraphrase XKCD, there are now N+1 regex explanations, and I apologize that mine is comparatively worse than all of them. :)

0: http://perldoc.perl.org/perlre.html 1: https://gist.github.com/gknoy/94c382299c4543f2e863