On Wed, Feb 20, 2002 at 01:15:36PM -0800, Simon Peyton-Jones wrote:
Another possiblity would be to make the ConCls class look like this class ConCls c where name :: String arity :: Int ...etc...
Now we'd have to give an explicit type argument at the call site:
show {| Constr c t |} (Con x) = (name {| c |}) ++ show x
I quite like the thought of being able to supply explicit type arguments.... but I don't konw how to speak about the order of type parameters. What order does map takes its two type parameters in?
Sorry, this seems like a non-sequitur to me? 'map' has type '(a->b) -> [a] -> [b]'; supplying explicit type parameters would mean giving values to 'a' and 'b'. If I wanted to propose notation for this, I would suggest, e.g., (map :: (String -> Int) -> [String] -> [Int]) length ["Hello", "World"] 'name' (above) has type 'String'; the '{| c |}' is not providing a type parameter in the same sense. What am I missing? Best, Dylan