Symbolic name as type constructor

Question

Sorry, newbie question about Haskell ...

What do I need to do to use the infix character as a type constructor? I found the following piece of code, but GHC and GH complain of "Unexpected type` ~>" where a type variable is expected "...

class Category (~>) where
(.) :: (a ~> b) -> (b ~> c) -> (a ~> c)
id  :: a ~> a

How can I do that? Thank you very much in advance!

Answer 1

Starting with GHC 7.6, everyone is TypeOperatorsalways a constructor . I am not sure why this is so, but I assume that this violation is not to violate even older code. Additional information on the mailing list.

Answer 2

Infix :. :~>

http://www.haskell.org/ghc/docs/7.0.3/html/users_guide/data-type-extensions.html