Proposal: Num instance for tuples

Anthony Cowley acowley at
Thu Oct 18 23:36:25 CEST 2012

On Thu, Oct 18, 2012 at 4:47 PM, Ivan Lazar Miljenovic
<ivan.miljenovic at> wrote:
> On 19 October 2012 04:57, Henning Thielemann
> <lemming at> wrote:
>> On Thu, 18 Oct 2012, Brent Yorgey wrote:
>>> I am +1 for this proposal, but only as long as these instances are not
>>> exported by the Prelude.  They are useful when you know you want them
>>> but will confuse newbies -- based on evidence from #haskell, where
>>> lambdabot has such instances in scope.
>> Please no orphan instances - I think a pair type that supports arithmetics
>> deserves a custom type.
> Agreed.  Another -1 on the proposal from me.

I am also with Henning, and a -1 for the proposal. If it's too
confusing to export by default, then the instance belongs to a less
general type. There are appropriate types that have the desired
behavior all over hackage. I am currently partial to V2 from the
linear package.


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