Proposal: generalise Monoid's mconcat

[Fumiaki Kinoshita]

-1

I would rather propose removing mconcat from Monoid. I've never seen
mconcat defined.

2015-09-01 17:04 GMT+09:00 Edward Kmett <ekmett at gmail.com>:

> To be clear I was referring to the generalization of mconcat, not to
> Petr's Dual suggestion
>
> That said, I have a very strong issue with the proposed change to Dual's
> mconcat. The issue with the Dual suggestion is that reverse requires the
> list to be finite. This means that even if the monoid could be productive
> before with Dual it can't with that definition.
>
> -Edward
>
>
>
> On Tue, Sep 1, 2015 at 12:56 AM, Edward Kmett <ekmett at gmail.com> wrote:
>
>> I'm personally -1 from a base organizational standpoint following Reid's
>> reasoning.
>>
>> This is just me expressing my own personal opinion rather than any
>> official core libraries committee stance at this time.
>>
>> -Edward
>>
>> On Mon, Aug 31, 2015 at 1:19 PM, Petr Pudlák <petr.mvd at gmail.com> wrote:
>>
>>>
>>>
>>> 2015-08-31 21:00 GMT+02:00 David Feuer <david.feuer at gmail.com>:
>>>
>>>> The theory of mconcat is that it should handle monoids that need to be
>>>> summed in some special way. I don't know if anyone actually uses it so,
>>>> however. Still, Reid is right that the circular dependency sets a very high
>>>> bar.
>>>>
>>>> I guess the [a] monoid is a good example where using mconcat can make a
>>> difference.
>>>
>>> What seems to be an omission is that Dual has no implementation of
>>> mconcat. It'd make sense to define 'mconcat = mconcat . reverse' - if the
>>> original monoid benefits from a certain order of operations, we should keep
>>> the order.
>>>
>>> _______________________________________________
>>> Libraries mailing list
>>> Libraries at haskell.org
>>> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>>>
>>>
>>
>
> _______________________________________________
> Libraries mailing list
> Libraries at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.haskell.org/pipermail/libraries/attachments/20150901/a8c12098/attachment.html>