[Haskell-cafe] Partial instance of a class

[Jeroen Bransen]

>> In my concrete case I think a profunctor is indeed the thing I was looking
>> for
> If you're willing to share your datatype I may be able to help determine
> exactly what sort of thing it is.  I have extensively explored the place of
> profunctors :)
http://hackage.haskell.org/package/progress-reporting-1.1.0/docs/Control-Monad-Progress.html

It's a class of functions (that may run in some monadic context) for 
which we can report progress. I can lift certain types of functions to 
this space (those that construct items of a list, or those that report 
their own progress in some way), and then these compose in several ways. 
Obviously having the first and second combinators from arrows comes in 
handy.