| I'd like to summarize the relationship between functional dependencies
| and type functions, and propose a solution that should get rid of
| overlapping instances. The solution does not require messing with
| System-FC. In fact, it can be implemented today (although
| ungainly). A small bit of
At Fri, 17 Jun 2011 13:21:41 +,
Simon Peyton-Jones wrote:
Concerning 1. mutual dependencies I believe that equality
superclasses provide the desired expressiveness. The code may not
look quite as nice, but equality superclasses (unlike fundeps) will
play nicely with GADTs, type
| By equality superclasses, do you just mean being able to say a ~ b
| in a class context?
Yes. Or (F a ~ b).
| Unless I'm missing something, that is not sufficient to do a lot of
| things I would like to do, as those things require both
| OverlappingInstances and FunctionalDependencies (as
