Ah, I didn't foresee those ambiguities, but now I see what you mean.  I've added your instance below (exactly how this sort of thing comes out for me as well), used in Test.hs, and pushed & released reactive-fieldtrip-0.0.4.  And yeah, adding a 'pure' to promote static to dynamic is pretty easy.

Note that now Test.hs imports FRP.Reactive.FieldTrip (a new collect/re-export module) instead of FRP.Reactive.FieldTrip.Adapter.

Thanks for the suggestion, Greg.

  - Conal

On Mon, Nov 24, 2008 at 3:56 PM, Greg Fitzgerald <garious@gmail.com> wrote:
>> static transformations of dynamic geometry.
>> dynamic transformation of static geometry and dynamic transformation of
>> dynamic geometry.  And the corresponding three additional instances for 2D
>> geometry.  All six would be very useful.

Implementing just the dynamic transformation of dynamic geometry seems
to work out best.

instance Transform xf a => Transform (Behavior xf) (Behavior a) where
  (*%) = liftA2 (*%)

With the other instances, GHC complains about ambiguities, and it's
easy enough to pull either side up into the dynamic realm.

Thanks,
Greg