Instead they've been, very slowly, turning C# into F#, which is even weirder to watch.
I miss writing it; I haven't had a job using it in a few years but I really enjoyed writing code in it when I did. Most of my personal projects haven't really been able to use .NET for awhile, so I never seem to have an excuse to play with F# in my personal time.
I never got into C#, so I can't say that I really feel the pain of the C# transition into F#.
[1] At least in the typed world. I'm also really partial to Clojure.
I'm not. I find F#s syntax much more pleasing and elegant, and I'm afraid F# will wither away when C# is a watered down version of it.
Something that helps, a ton, is as you're transitioning, you can write code almost identically to how you did before. It doesn't force FP on you at all. It's less useful if you try to do that, because you're not taking advantage of the language, but it makes testing your beliefs on how things work SUPER easy because you can set it up in the OOP way, get the result you expect, then set up in what you think is the correct FP way, and see if it matches.
The only issue is there's a severe lack of beginner friendly documentation (although it's leagues better than it used to be). I honestly think that if you're a C# dev, it's probably worth giving it a weekend or two to play with. ESPECIALLY if you like linq syntax.
To be clear, it's not like I'm new to functional languages and their type systems, I've been doing Haskell for forever, and I did F# for a multiple years, but Scala has never really clicked for me.
Personally, for doing JVM stuff, I'm a pretty die-hard Clojure advocate. I feel like it's easy for me to write Clojure in the way that I think, while still allowing me to mooch off the entire Java ecosystem, and if there are things that I don't like about the language it's really not that hard to macro in a new feature (though obviously this should be used sparingly).
I definitely recommend giving F# a try. I think it's an extremely underrated language.
That was a bit of a surprise - I’d forgotten how expressive Scala is. I didn’t need any “advanced” type system features. But my time to market was literally a couple hours instead of days like with C#, Java, Kotlin, Go, bending to fit the logic into the confines of their type systems. Kotlin is just awesome and very expressive. But it turns out, to me, Scala is somehow very natural - just write what you think, and it works.
Interestingly, that was also my experience many years ago when I first exposed myself to Scala in a numerical analysis class just to avoid Java, and it just worked right away. I recall well that surprised feeling. So I’m kinda happy to move back to Scala now. But I’ll also try to implement the same in F#, right after delivering the next feature set.
Do you have any recommendations for people who do not have C#/.NET experience who want to rip their toes in F#? The last time I tried the language I bumped my head on the .NET parts. :/
For the most part I didn't need most of the built in .NET libraries; the F# stuff was fine, but the ones I ended up using a lot were the threadsafe libraries for when I needed mutation across threads. ConcurrentDictionary was one I used an awful lot, ConcurrentBag occasionally, SemaphorSlim, and Interlocked Incrementors.
The reason that the .NET compatibility was handy to me was because it made it easy to get third party libraries without much fuss, which was great because they were generally pretty well supported.
The rule of thumb that I used was that F#, while it kind of looks like Haskell, is not Haskell, and specifically it's not lazy, and as such I always kind of pretended I was in the `do` block. Things execute top down, and you can mix in side effects wherever, so you kind of have to pretend everything is in an IO monad, or at least if you see anything that has a side effect in there.
[1] I was hired at Jet.com specifically because I had Haskell and Erlang experience prior. I had never written any significant C# code before.
Also, having the documentation split between the F# parts on one site and the .NET parts on another site was a bit of a pain.
It might have gone better if I was starting with a book instead of picking docs off the web.
FWIW I think it works fine with Nix, so if you're not opposed to using that package manager it should pretty trivial to get different versions working with a nix shell and/or flake.
In F#'s case, there are plenty of good books, and then it is really needed to learn the platform.
Some well known ones => Stylish F#, F# in Action, Domain Modeling Made Functional
From what I've seen, Scala3 is better in this regard (at least the magic part), but I since Spark doesn't support it yet, my exposure to it has been limited.
Thing is the community doesn't reach that often to them.