On Sun, Jan 8, 2012 at 9:25 PM, Brent Yorgey <byorgey@seas.upenn.edu> wrote:
On Fri, Jan 06, 2012 at 10:51:58AM +0000, Steve Horne wrote:
>
> If I specify both extensions (-XMultiParamTypeClasses and
> -XFlexibleInstances) it seems to work, but needing two language
> extensions is a pretty strong hint that I'm doing it the wrong way.

Not necessarily.  These two extensions in particular (and especially
the second) are quite uncontroversial.

I really don't know much about the subject, but

http://hackage.haskell.org/trac/haskell-prime/wiki/MultiParamTypeClassesDilemma

does not sound "uncontroversial" to me. That's why I avoided them so far.

- Chris