It's becoming more common to see "Functional Programming in X". Why don't we use functional languages like oCaml or Haskell more often? Are we making the jump in two steps instead of one? I've never written more than a few lines of either so I can't tell if something "better" is waiting for me in functional land.
Why are there so very few programs written in say, haskell, that you actually want to use?
This is a serious question that I haven't found the answer for. Around here people suggest pandoc, shellcheck and sometimes the xmonad window manager as pretty much the full list of things you can install, use and hack on written in haskell whose purpose isn't writing haskell code.
Given the popularity of haskell amongst hackers and the various claims about its benefits and strengths, the fact this list is so small (if it's larger and I'm missing a bunch - please DO let me know, I want to play with them and hack on them!) Is something I have difficulty reconciling with haskell being a useful general purpose programming language. Maybe they're being written now and they're on their way? But haskell has been around for more than a few years now. Maybe haskell hackers just mostly hate open source & free software unless it's GHC or a general purpose library? Seems unlikely. So maybe something else I don't yet understand. It is puzzling when I don't code in the language fluently enough to understand its weaknesses as opposed to my own in coding in the language and it's a point the many lovers of haskell never seem to address other than with extreme defensiveness which kind of misses the point of the question.
> Why are there so very few programs written in say, haskell, that you actually want to use?
I think a big part of it was struggling with cabal hell. I know that quite a bit of web development and API stuff is happening with Haskell since I've gotten paid to do some for multiple clients (some requesting Haskell).
I think that with the release of stack[0] (and it eventually being merged into the Haskell platform IIRC) many application developers will start to pick up Haskell and create those types of programs.
Not open source, but an application created in Haskell was bump[1].
Probably because its easier to see the use of functional paradigms in languages you're familiar with. OCaml and Haskell are great languages, but they require a lot of new learning at once.
You are right about it being nice to see functional code in your language. However, from my learning experience I understood the functional style much better by using actual functional language. I started with Scheme which has very minimal easy to understand syntax. Many courses ask students to try forget whatever they know about programming before introducing functional style. If that helps (for me it did), I think starting with new language would be nice decision.
There are many steps between functional programming in, say, Python, and writing everything in Haskell. Many differences. Not everybody has the same opinion of all those differences.
I'm often missing a feature to make language X act in a purely functional way (i.e., to disable side effects completely in a relevant part of the code).
Also missing is a way to select between strict or lazy evaluation.
