Re: Proposal: generalise Monoid's mconcat

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 wrote:

2015-08-31 21:00 GMT+02:00 David Feuer :

...

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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