[Haskell-cafe] Num instances for 2-dimensional types

Jacques Carette carette at mcmaster.ca
Mon Oct 5 11:11:22 EDT 2009

Lennart Augustsson wrote:
> Everyone agrees that the Haskell numeric hierarchy is flawed, but I've
> yet to see a good replacement.
That's because the "good replacement" which is mathematically sound 
would be a real mess to work with -- for exactly the same reason that 
Functor , Applicative and Monad are unrelated classes.  See [1].

In a prototype language I am playing with, my version of Num depends on 
15 'previous' classes, and that's likely to increase, not decrease.


[1] http://repetae.net/recent/out/classalias.html

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