Proposal: generalise Monoid's mconcat

[Edward Kmett]

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.
>
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