Is it possible to define a generic extension method in F#?

If I understand your question correctly, the answer is no Section 8.12.1 of the spec (Imported C# Extensions Members) includes this text: C#-defined extension members are made available to F# code in environments where the C#-authored assembly is referenced and an open declaration of the corresponding namespace is in effect. However, some limitations apply, notably C# extension members whose “this� Parameter is a variable type are not made available to F# code in this version of F C# extension members whose “this�

Parameter is an array type are not made available to F# code in this version of F This explains why some extension methods from C# will work (e.g. Those in System. Linq), while the one that you are attempting to use will not Furthermore, native F# extension methods can only be defined as if they were placed on actual type definitions. In particular, you can't define an F# extension method on a closed generic type (e.

G IEnumerable.

If I understand your question correctly, the answer is no. Section 8.12.1 of the spec (Imported C# Extensions Members) includes this text: C#-defined extension members are made available to F# code in environments where the C#-authored assembly is referenced and an open declaration of the corresponding namespace is in effect. However, some limitations apply, notably C# extension members whose “this�

Parameter is a variable type are not made available to F# code in this version of F# C# extension members whose “this� Parameter is an array type are not made available to F# code in this version of F# This explains why some extension methods from C# will work (e.g. Those in System. Linq), while the one that you are attempting to use will not.

Furthermore, native F# extension methods can only be defined as if they were placed on actual type definitions.In particular, you can't define an F# extension method on a closed generic type (e.g. IEnumerable) nor can you define an extension method on a generic type variable.

Thank you for the answer! – Vagif Abilov Aug 2 '10 at 8:29.

As kvb mentioned, it's not possible in F# 2.0. In this particular case I'd wrap Rhino. Mocks fluent interface to make it more idiomatic in F#, e.g. : let mstub f target = RhinoMocksExtensions.

Stub(target, Function(f)) let mreturn value (options: IMethodOptions) = options. Return value let service = MockRepository.GenerateMock() service |> mstub (fun s -> s. Compare(1,2)) |> mreturn 1 |> ignore What's fluent in one language is not necessarily fluent in another.

(sorry for the plug but I really think it's relevant here).

Marurcio, Thank you for the explanation. Yes, I also came to the same conclusion that such extensions that are quite useful in C# wouldn't bring that much value to F#, and there are other (and better) ways of expressing this in F#. – Vagif Abilov Aug 2 '10 at 8:32.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.