Proposal: Num instance for (a -> b)

[Henning Thielemann]

On Sun, 11 Nov 2018, Dannyu NDos wrote:

> I suggest adding this as an orphan instance (Like Show (a -> b)) in a seperate module (say, Numeric.Function).

https://hackage.haskell.org/package/NumInstances

It would not save much, because in a reasonably big project you will 
somewhen import a package that transitively depends on the module. E.g. 
'diagrams-canvas' depends on NumInstances.