Num superclass of Bits (Was: Proposal: Remove Show and Eq superclasses of Num)

Henning Thielemann lemming at henning-thielemann.de
Fri Sep 16 14:12:39 CEST 2011


On Fri, 16 Sep 2011, Herbert Valerio Riedel wrote:

> 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...

Me too. For instance when working with flag sets like in [1], addition, 
multiplication, absolute value, number literals make no sense.

[1] http://hackage.haskell.org/package/enumset



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