[Haskell-cafe] Why no Monoid, Num, Integral, or Floating RVarT instances?

Barend Venter barendventer at gmail.com
Tue Aug 23 04:17:26 CEST 2011

It seems like you should be able to get instances for:

(Monoid m) => Monoid (RVarT n m)
(Num m) => Num (RVarT n m)

and so forth for integral and floating

Just wondering if I am missing something here or if there is any
particular thing I'm missing. I am aware you would probably not be
able to do an Eq or Show instance but me understanding was that in the
case of the (Num b) => Num (a -> b) instance the solution was simply
to leave those things undefined.

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