[Haskell-cafe] Client-extensible heterogeneous types (Duck-typed variadic functions?)

[Jacek Generowicz]

On 2010 Oct 15, at 13:32, Jacek Generowicz wrote:

>    questions = [ addition 1 2, addition (1%2) (1%3) ]


> My problem is that I don't see where I could add a type signature,  
> but still keep
>
>   addition :: a -> a -> Question
>
> polymorphic.

Well, OK, I could write

     addition 1 (2 :: Int)

inside the question list, but that's rather ugly, and it would be  
immensely annoying to have to do this for every specific question.

  Is there anywhere else it could go ?