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Becoming an F# contributor

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82 pointsnumo1623 comments

It's strange how appealing F# becomes once you realize you have the full power of the Visual Studio debugger and the .NET libraries. To someone who has mostly worked with Haskell (w.r.t. functional languages), that sounds great. Good debugging is absolutely essential - though with strongly typed functional languages, it's not often that necessary. But it's nice.

Then again, it's a very liberal language, if the end of the spectrum is Haskell. It allows side effects and mutable variables. While very convenient, nothing forces you to use these though. There are immutable data structures for everything. But it seems there are all the functional tools you'd want.

It's not Haskell, it's not pure and beautiful like it, but you still have computational expressions, which allow you to implement monads; metaprogramming, operator overloading, units of measure, and active patterns.

My only gripe is that the compiler doesn't translate functions that can return null to return an option value (i.e. Maybes), and null values in general! Would make interfacing the .NET library much cleaner. Right now I have to do something silly like this:

  let notNull a = if a <> null then Some a else None

So I have to pipe every function call that may return null to this function when I'm in the Maybe monad, which is frankly a bit bothersome.

Still. Even being able to use the Maybe monad when working with .NET is really cool.

> Then again, it's a very liberal language, if the end of the spectrum is Haskell. It allows side effects and mutable variables.

Like the majority of ML languages. Haskell is pretty special here, being the descendant of Miranda.

Personally I think ML languages of OCaml branch are better for the general programmer public, as the entry level is a lower.

For those who may be interested in contributing to the OCaml language, the Compiler Hacking Wiki is a good place to start.

https://github.com/ocamllabs/compiler-hacking/wiki

If I recall correctly I think at some point Ocaml required a paid developer licence to be obtained from Inria. Has this changed or am I just misinformed?

Not that I'm aware of. AFAIK anyone can submit a patch to OCaml without any hurdles. There is a Consortium that companies can join and they benefit from a different licence. That might be what you're thinking of.

http://ocaml.org/community/support.html#TheCamlConsortiumatI...

Thanks for the clarification!

How do you feel about having a different set of operators for integers and reals? Like "+." versus "+".

how to you feel about the overloaded use of `=` in C?

I'm not sure I understand what you mean. `=` is only assignment in C (or Java, or C#, or most any language I know of). `==` is comparison, being a different operator, one wouldn't say `=` is "overloaded".

Two different operations, two different operators. Yes, C famously makes it easy to miss the extra `=` in if expressions, but that's C specifically, and it's not the fault of the operator, that's actually the fault of automatic conversions from int to bool. Static languages designed after I was born usually require boolean expressions in their `if` statements explicitly.

But `+` and `+.` are the same operation. Or are you saying that adding integers and adding reals are not the same operation, and thus warrant separate operators?

I've begun to like having '+' and '+.' operators in OCaml. Not that I'm never tripped up, I often am, but I can never hide implicit conversions.

Another thing to consider is how you would implement having '+' for both integers and floats. In a language like C, '+' is designed for its numerical types, but what if you want to use it for big ints? Or for vectors? In a language like C++ you can overload operators, in Haskell or Rust operators are part of a typeclass or trait respectively; you need to add extra features to the language and the code generated by '+' is no longer a simple iadd or dadd instruction.

OCaml's choice may not be the best one or the most popular one, but I think it works fine.

Perhaps you know this, but just for the sake of precision and avoidance of doubt: Haskell numerical operations don't actually do any sort of conversion.

F# use the same + operator

  > 1.0;;
  val it : float = 1.0

  > 1;;
  val it : int = 1

  > 3.0 + 1.0;;
  val it : float = 4.0

  > 3 + 1;;
  val it : int = 4

or strings

  > "3" + "4";;
  val it : string = "34"

implicit conversion is not supported (good ihmo)

  > 3.0 + 1;;

  3.0 + 1;;
  ------^

  stdin(5,7): error FS0001: The type 'int' does not match the type 'float'

I'd be fine with that. The OCaml way just seems needlessly preachy.

I don't have any issue with them.

My first contact with functional programming was with Caml Light back in 1996, OCaml's predecessor, which already has them.

My favourite programming languages are strong typed (e.g. Ada), so I guess it just felt natural back then.

However F# is the favourite one as nowadays I spend most of my time on Windows.

tl;dr

The F# language has been open source for 4 years and MS has accepted pull requests to the compiler, core library, and tools for over 6 months (100+ PRs going into F# v4.0). Now with Microsoft fully committed to open source and cross-OS development with .NET Core, this is a very good time for hackers interested in meta-programming to get in on the ground floor of F#, the only functional language fully supported by .NET.

This article is a complete guide to hacking on the F# core, in this case an end to end example of extending the core library, including setting up standard unit tests. And mentions looking to F# Language Design User Voice, http://fslang.uservoice.com/ as the source for extension inspiration. One thing mentioned in the article, that F# will "likely" move from codeplex to Github, should read that the MS team is committed to fully migrate to Github, they are just busy right now with v4.0 of the language.

I'm still hesitating between learning Common Lisp or F# for my next web service project. I work with C# in my day job, so F# seems like a no brainer, but I'd like to get away from the CLR and there isn't much out there on getting F# running with vnext on linux (digital ocean).

Any opinions?

As for the posted link, quite interesting, a similar one for C# would be cool.

Yeah I wouldn't spend time on F# on non-Windows until the community builds up more. So you probably want to try either OCaml or, if you're up for a bigger challenge, Haskell.

How are the Mac and Linux Mono versions? Are they production ready? It's not really about the "bigger challenge", but being able to ship code that solves real problems for clients.

This gets discussed every so often on the mailing list https://groups.google.com/forum/#!topic/fsharp-opensource/AX...

This is actually my impression, that Mono isn't at the same level of performance than the windows counter-part. I guess we can expect with .Net Core to see improvements. But will the Mono runtime ever be as good as the CLR ? The CLR isn't open sourced. The whole open-sourcing happening in the .Net world is quite interesting, but It is also confusing the hell out of me.

The CLR will be open source very soon though.

TL;DR .net core = surgery of .NET Libraries for crossplat cleanup + RyuJIT Virtual Machine (clr)

The clr will be open source (with new RyuJIT jit compiler), it's happening one commit at time :D

open source CLR/full .NET = readonly sources MIT (and mono can import fixes to BCL)

.NET Core = RyuJIT VM + .net Core BCL libraries + redesigned for modularity + CrossPlat + Development on github

Mono will maybe merge with corefx

Open source components are: - the .NET Framework Libraries (BCL of full .net) - NET Core Framework Libraries (BCL of new .net core) - RyuJit VM

more info * Miguel de Icaza (MONO) post http://tirania.org/blog/archive/2014/Nov-12.html * Microsoft post http://blogs.msdn.com/b/dotnet/archive/2014/12/04/introducin...

You should ask on the fsharp-opensource[1] mailing list; a large portion (maybe even a majority) of the posters on there are using Mac/Linux/BSD for their F# development/deployment.

[1]: https://groups.google.com/forum/#!forum/fsharp-opensource

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