How can I use and call Haskell functions with higher-order type signatures from C# (DLLImport), like...
double :: (Int -> Int) -> Int -> Int -- higher order function
typeClassFunc :: ... -> Maybe Int -- type classes
data MyData = Foo | Bar -- user data type
dataFunc :: ... -> MyData
What are the corresponding type signature in C#?
[DllImport ("libHSDLLTest")]
private static extern ??? foo( ??? );
Additionally (because it may be easier): How can I use "unknown" Haskell types within C#, so I can at least pass them around, without C# knowing any specific type? The most important functionality I need right know is to pass around a type class (like Monad or Arrow).
I already know how to compile a Haskell library to DLL and use within C#, but only for first-order functions. I'm also aware of Stackoverflow - Call a Haskell function in .NET, Why isn't GHC available for .NET and hs-dotnet, where I didn't find ANY documentation and samples (for the C# to Haskell direction).