6 Feb
2008
6 Feb
'08
10:36 a.m.
On Wed, 6 Feb 2008, Denis Bueno wrote:
On Feb 6, 2008 9:40 AM, Henning Thielemann
ok, maybe with functional dependency t -> x
I'm not sure about that. It's often convenient to have two instances, one like the one I gave above, and others involving something that embeds a key-value pair:
type SomethingWithKV k a = KV {getKV :: (k, a)} instance Buildable (Map k a) (SomethingWithKV k a) where empty = Map.empty insert s m = uncurry Map.insert (getKV s) m
I have done this before -- it's very convenient, and I think makes the code that uses empty and insert more robust, and easier to read.
But why do you want to have the special type SomethingWithKV, but not MapSomething ?