[Haskell-cafe] Re: Positive integers
lemming at henning-thielemann.de
Fri Mar 24 14:44:25 EST 2006
On Fri, 24 Mar 2006, Aaron Denney wrote:
>> Without breaking compatibility?
>> But class instances become invalid if the hierarchy is modified.
> No, compatibility will be broken. Hopefully not for most uses -- I
> don't think most people define new instances, and those that do will be
> able to do so more reasonably, so hopefully wouldn't mind.
There are a lot of instances of Num around. Everywhere where Haskell is
used as a wrapper to other languages like CSound, SuperCollider, metapost
new numerical instances are defined. Since restructuring the numerical
type class hierarchy would break them I assumed that a modified hierarchy
is out of scope of Haskell'.
> Not at all. That is one of the things I looked at a while ago, that has
> inspired a lot of my decisions -- but I'm more willing to rename things
> that I think have silly names. And there are a few minor details, like
> allowing only for euclidean domains rather than principal ideal domains.
> I will probably actually put two proposals up, with one allowing more
> generality via MPTCs and FDs (which I truly hope make it into the
Whatever you propose for Haskell' feel encouraged to also contribute
improvements to NumericPrelude.
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