On Fri, 2011-09-16 at 02:41 +0100, Ian Lynagh wrote:
I would like to propose that we remove the Show and Eq superclasses from Num, i.e. change class (Eq a, Show a) => Num a where [...] to class Num a where [...]
This will break client code, but will not fix other defects of Num,
It doesn't solve everything, but I hope we can agree it is an incremental step in the right direction. I don't think a revolutionary change fixing all the issues is feasible. This particular blemish was already being described as "largely historical" more than a decade ago: http://www.haskell.org/pipermail/haskell/2000-October/006147.html
+1 Just as a side note: I also dislike that the Data.Bits.Bits type-class has Num as its superclass; If I need something to be an instance of the Bits class for the bit-ops, I don't usually want to be forced to provide multiplication and addition operations as well...