Re: [Haskell-cafe] Type families not as useful over functions

On Fri, 2009-02-13 at 11:15 +1100, John Ky wrote:

Hi Johnaton,

Ah yes. That makes sense. Is there a way to define type r to be all types except functions?

Not without overlapping instances. I *think* if you turn on {-# LANGUAGE OverlappingInstances #-} then instance Broadcast r where type Result = [r] broadcast xn = xn should do what you want (instance resolution delayed until r has a type constructor at top level; this instance selected if no other instance is in scope --- should be equivalent to r not a function type unless someone else defines an instance!); but I know that's not a pretty way of doing things. jcc