[Haskell-cafe] Monoid wants a (++) equivalent

Bryan O'Sullivan bos at serpentine.com
Tue Jun 30 19:17:40 EDT 2009


On Tue, Jun 30, 2009 at 3:56 PM, Ross Paterson <ross at soi.city.ac.uk> wrote:

> On Tue, Jun 30, 2009 at 03:39:39PM -0700, John Meacham wrote:
> > (+>) seems to imply to me that the operator is non-associative.
>
> It does seem to imply some asymmetry between the arguments.
>

Well, the canonical instance of Monoid is to mappend over lists, where it
doesn't commute, so I think that the pointiness of the operator makes a
reasonable kind of sense.
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