Proposal: generalise Monoid's mconcat

[Reid Barton]

On Mon, Aug 31, 2015 at 1:54 PM, Fermin Reig <ferminreig at fastmail.fm> wrote:

> We could generalise:
>
> mconcat:: [a] -> a
> mconcat = foldr mappend memtpy
>
> to:
>
> mconcat:: Foldable t => t a -> a
> mconcat = foldr mappend memtpy
> -- even
> -- mconcat = fold
>

I don't understand the appeal of generalizing the type of a function when
the generalization already exists; but in this case it's not a viable
option anyways because mconcat is a class method of Monoid, and the
definition of the Foldable class already refers to Monoid. Creating a
circular dependency of Monoid on Foldable would be a headache best avoided.

Regards,
Reid Barton
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