Survival of generic-classes in ghc

[Simon Peyton-Jones]

| > Another possiblity would be to make the ConCls class look like this
| > 	class ConCls c where
| >  	  name :: String
| > 	  arity :: Int=20
| > 	  ...etc...
| >=20
| > Now we'd have to give an explicit type argument at the call site:
| >=20
| >       show {| Constr c t |} (Con x) =3D (name {| c |}) ++ show x
| >=20
| > I quite like the thought of being able to supply explicit type=20
| > arguments.... but I don't konw how to speak about the order of type=20
| > parameters. What order does map takes its two type parameters in?
|=20
| Sorry, this seems like a non-sequitur to me?
|=20
| 'map' has type '(a->b) -> [a] -> [b]'; supplying explicit=20
| type parameters would mean giving values to 'a' and 'b'.  If=20
| I wanted to propose notation for this, I would suggest, e.g.,
|   (map :: (String -> Int) -> [String] -> [Int]) length=20
| ["Hello", "World"]
|=20
| 'name' (above) has type 'String'; the '{| c |}' is not=20
| providing a type parameter in the same sense.

Yes it is.  'name' would have type
	forall c. ConCls c =3D> String
It requires a type argument, just like map.

Simon