At Thu, 27 Aug 2009 10:47:43 -0400, Job Vranish wrote:
I've often wanted an applicative instance for a datatype that didn't match the monad instance.
It would be nice if there was a way to hide instances so that they could be redefined.
Yeah, this is similar to the issue of multiple sensible instances for Data.Monoid. This issue has come up several times for me recently. A bit of a shortcoming in the type class design I think. There was once a proposal to help address this, but it never gained tracation: http://scholar.google.com/scholar?hl=en&lr=&cluster=8306039955712318110&um=1&ie=UTF-8&ei=JTmXSvmTJ4a4M6TJlfkN&sa=X&oi=science_links&resnum=1&ct=sl-allversions Recently I have wondered if module functors might somehow be a solution somehow. But I have not actually investigated at all. - jeremy