4 ms·

Consuming C# code from F# works fine. Consuming F# code from C# works pretty well for the most part, although F# specific types are cumbersome to use (records,

Consuming C# code from F# works fine. Consuming F# code from C# works pretty well for the most part, although F# specific types are cumbersome to use (records, discriminated unions, computational expressions aka monads). This just means that if you want an F# DLL to be usable from C#, you need to think a little bit about the exposed API (perhaps by adding a C# specific wrapper). Having said that, IMO the interop between the two is better than the interop between JVM languages like java, scala & clojure (Kotlin is probably different).

tigershark 11y ago
Yes, I agree, but you need to be really careful about tail call recursion optimisation when calling f# code from c#. In F# it is always guaranteed, in c# only on 64 bit 4 and above runtime if I remember correctly, so you can't really rely on it for production code.
- RaleyField 11y ago
  Wouldn't C# interface only with compiled il code and not directly with F# so any tail call optimizations in F# wouldn't depend on what you later do in C# compiler?
  - tigershark 11y ago
    Yeah, right, the f# compiled code will be already optimised for the tail call recursion so it can be called safely from the c# code. What I remembered applies only to the c# generated IL.
- MichaelGG 11y ago
  Unless it's changed, F# doesn't emit "tail." prefixes for tailcall. Nor is it guaranteed. The F# compiler will, in some cases, manually turn your tailcall-OK code into a loop. But it doesn't do it in all cases (nor could it). The F# compiler used to emit "tail." prefixes in every case that was eligible. But not only does the CLR have lots of restrictions, it was slower to request tailcalls. Maybe that changed in the last version or two. Edit: OK I found the email where I had asked fsbugs why tailcalls were no longer generated. But that was in 2009 so I'm more out of date than I remember. In the release notes[1] for the May 2009 release, there's this section: Optimizations for Tailcalls On some implementations of the CLI, normal calls can be more efficient than tailcalls. An optimization is now applied to determine if a function is “closed” in the sense that it never takes any tailcalls outside a finite non-recursive callgraph. If so, the use of tailcalls is suppressed. 1: http://blogs.msdn.com/dsyme/archive/2009/05/20/detailed-release-notes-for-the-f-may-2009-ctp-update-and-visual-studio-2010-beta1-releases.aspx http://blogs.msdn.com/dsyme/archive/2009/05/20/detailed-rele...
JBReefer 11y ago
In general you should follow Demeter's law and not expose types behind value types if you can avoid it.
- Koshkin 11y ago
  Regarding this 'law', Wikipedia put it quite nicely, saying quote, it is more suited as a metric for code smell as opposed to a methodology for building loosely coupled systems.
Too 11y ago
Have they fixed the intellisense yet? Last time I tried to call c# from f# it compiled but autocompletion in vs didn't work.
- bunderbunder 11y ago
  Yeah, the intellisense is a lot better than it was in earlier versions. That said, it doesn't attempt to read your mind, so the intellisense only kicks in when the type you're interacting with is unambiguous. So, for example, you'll need to explicitly state a function parameter's type before intellisense will help you figure out what methods you can call on it.

tigershark 11y ago

Yes, I agree, but you need to be really careful about tail call recursion optimisation when calling f# code from c#. In F# it is always guaranteed, in c# only on 64 bit 4 and above runtime if I remember correctly, so you can't really rely on it for production code.

RaleyField 11y ago
Wouldn't C# interface only with compiled il code and not directly with F# so any tail call optimizations in F# wouldn't depend on what you later do in C# compiler?
- tigershark 11y ago
  Yeah, right, the f# compiled code will be already optimised for the tail call recursion so it can be called safely from the c# code. What I remembered applies only to the c# generated IL.
MichaelGG 11y ago
Unless it's changed, F# doesn't emit "tail." prefixes for tailcall. Nor is it guaranteed. The F# compiler will, in some cases, manually turn your tailcall-OK code into a loop. But it doesn't do it in all cases (nor could it). The F# compiler used to emit "tail." prefixes in every case that was eligible. But not only does the CLR have lots of restrictions, it was slower to request tailcalls. Maybe that changed in the last version or two. Edit: OK I found the email where I had asked fsbugs why tailcalls were no longer generated. But that was in 2009 so I'm more out of date than I remember. In the release notes[1] for the May 2009 release, there's this section: Optimizations for Tailcalls On some implementations of the CLI, normal calls can be more efficient than tailcalls. An optimization is now applied to determine if a function is “closed” in the sense that it never takes any tailcalls outside a finite non-recursive callgraph. If so, the use of tailcalls is suppressed. 1: http://blogs.msdn.com/dsyme/archive/2009/05/20/detailed-release-notes-for-the-f-may-2009-ctp-update-and-visual-studio-2010-beta1-releases.aspx http://blogs.msdn.com/dsyme/archive/2009/05/20/detailed-rele...

JBReefer 11y ago

In general you should follow Demeter's law and not expose types behind value types if you can avoid it.

Koshkin 11y ago
Regarding this 'law', Wikipedia put it quite nicely, saying quote, it is more suited as a metric for code smell as opposed to a methodology for building loosely coupled systems.

Too 11y ago

Have they fixed the intellisense yet? Last time I tried to call c# from f# it compiled but autocompletion in vs didn't work.

bunderbunder 11y ago
Yeah, the intellisense is a lot better than it was in earlier versions. That said, it doesn't attempt to read your mind, so the intellisense only kicks in when the type you're interacting with is unambiguous. So, for example, you'll need to explicitly state a function parameter's type before intellisense will help you figure out what methods you can call on it.