Outside of web development any ideas what I could use it for (I am on Linux so it should run on Mono)? I've done quite a lot of web development on the JVM with Clojure, Scala and Java and would like to try to do something totally different with F#.
In my own tests, F# will require about 1/20th of the type annotations of C#. It offers a near superset of functionality, so you don't lose anything (except a bit on the tooling side of things).
The lightweight syntax, easy handling of functional features, nesting of code - it ends up leaving you with far less code that has less bugs by default. MS describes F# as excelling at "programming in the small" - the line-by-line, char-by-char code is simply far superior to using C#. Just type inference alone is huge - C# is embarrassingly bad at type inference, and it's partially due to the complexity in their codebase in implementing it properly. At the moment, MS seems to have sort of backed off on enhancing C#.
There's so many tiny things in F# that just make the code easier and less bug prone. For instance, being able to nest code. Suppose I want to read an integer out of a querystring, and on failure provide a default. Idiomatically, in C#:
int age;
if (!int.TryParse(qs["age"], out age)) age = -1;
In F#:
let age = try int qs.["age"] with _ -> -1
Or lets say I have some intermediate variables. In C#:
int age;
var parts = String.Split(bla, ",");
if (parts.Length == 0) age = -1;
else age = int.Parse(parts[0]);
I've introduced a useless local var, parts, for no reason other than needing it in computing age. In F# (and avoiding pattern matching just to demonstrate):
let age =
let parts = String.Split(bla, ",")
if parts.Length = 0 then -1 else int parts.[0]
The intermediate binding, is not available outside it's scope. That's far cleaner, and quite commonly useful.
Top level functions are handy. Being able to make useful lambdas without specifying the types is super useful. Many of my functions have a nested helper function which makes things cleaner. Places where I don't want to add a full utility function, but I don't want to repeat code. You can do it in C#, but it's ugly. In F# it's natural.
Array/list comprehensions. In C#:
var res = new List<int>();
using(var reader = cmd.ExecuteReader()) {
while(reader.Read()){
res.Add(reader.GetInt32(0));
}
}
In F#:
use reader = cmd.ExecuteReader()
let res = [ while reader.Read() do yield reader.GetInt32(0) ]
Pattern matching is well covered, and F# Active Patterns are just awesome, because you can customize your own destructuring for arbitrary objects. The list just goes on and on, lots of things in F# that are just so right, so easy, so trivial. Custom operators, tuple handling.
I'm not even touching on the larger things, like Type Providers, records, sum types, or the fact that F# has monad syntax that's flexible, instead of C# building specific monads into the language. Heck, the F# compiler is far more advanced and produces faster code in many cases. And the fact that you can manually make it inline code is also a nice perf win you simply cannot get with C#.
I recently started working on a project that uses C#, and it's just such a pain. Death by a thousand cuts. There's no reason to use C# over F#. Even if you only use F# as a light-syntax-C#, you're better off.
The only real objection is hiring, in an enterprise scenario. For any serious project where the code is the product (versus the code being an artifact of just solving a business problem), I don't believe you can hire any good programmer that cannot deal with F#. (I think that hold for most languages, in general.) Unfortunately, people don't seem to believe that, and somehow think they're going to hire really smart people, but these people aren't going to be able to learn a different language.
>At the moment, MS seems to have sort of backed off on enhancing C#
I assume you are talking about enhancing C# itself, because Roslyn is the next big thing for C# (and VB.Net) with a compiler compiler rewrite that will allow anyone to build language services.
The C# compiler code base is old now. It was done in C++ and apparently has become very hard to maintain. The C# team has been working on Roslyn, a complete rewrite of the compiler in C#, to make adding new features to the language more easily. It will also allow improvements to tooling (anyone can use the same compiler service rather than create their own) and should certainly facilitate meta-programming, construction of DSLs, etc.
I agree with you about F# though. It's so much to-the-point than C#, which is already a big improvement on java and C++ in the terseness area.
I love C# but I wish I was at least as proficient in F#, I know I could be a lot more productive with a language that requires less 'ceremony'.
Right, I'm referring to the fact that C# 3 added LINQ, but with the bare minimum of features for LINQ. Type inference, for example, is purely for anonymous types and the LINQ extension methods. They never went back to clean those up since V3, and it doesn't seem like they care.
Maybe this magical Roslyn rewrite is going to enable all sorts of amazing things, and then C# will rapidly catch up. But from the outside, it feels like C#'s good enough (hey, it's better than Java), and MS is content to keep it that way.
In another thread somewhere, it was said that with Roslyn they are holding off on adding new language features as every item they add is another step from completing Roslyn. Once it's out the door, there will be another flurry of features added.
Having said that, I already hear people complaining about the pace of new .Net frameworks and language features being too fast. I think that the community seems to be split on whether to add new language features or not
One place some predict it will emerge is in the Web API arena, and I could totally see that happening.