Can you define namespace-less extension methods compatible with C#?

Question

I know you can define empty namespace extension methods in c#, can you define the same methods in F# for consumption by C#? I followed this general post on getting C# compatible extension methods, but I'm not having any luck figuring out the final step for a 1-1 conversion.

this is not a duplicate, I'm looking for the way to define extension methods that are in the global namespace as far as C# is concerned, not how to define regular extension methods in F# that C# can see.

possible duplicate of [F# extension methods in C#](http://stackoverflow.com/questions/702256/f-extension-methods-in-c-sharp) — GregRos, Mar 15 '15 at 02:11
This is a duplicate of http://stackoverflow.com/questions/702256/f-extension-methods-in-c-sharp. If you're asking whether the same extension method you define in F# can be visible in C#, the answer is a definite no. The way the languages handle extensions is completely different. — GregRos, Mar 15 '15 at 02:12

Gene Belitski · Accepted Answer · 2015-03-15T08:31:57.783

You definitely can create such extension methods in F#. This may be achieved via Global Namespace exploiting the feature that an F# module declared outside of any namespace gets into this default global namespace as in the snippets below:

// Tested under Visual Studio 2013 Premium/F# 3.1:

// F# library module
[<System.Runtime.CompilerServices.Extension>]
module Extension
    [<System.Runtime.CompilerServices.Extension>]
    let Superb(s: System.String) = "Superb!!!"

and

// Use extension method on System.String from C# console app:
class Test
{
    static void Main(string[] args)
    {
        System.Console.WriteLine("abc".Superb());
    }
}

Can you define namespace-less extension methods compatible with C#?

1 Answers1