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

Daniel Peebles pumpkingod at gmail.com
Tue Jun 30 14:44:50 EDT 2009


Except that in this case the operator is associative :P

On Tue, Jun 30, 2009 at 2:42 PM, David Leimbach<leimy2k at gmail.com> wrote:
>
>
> On Tue, Jun 30, 2009 at 10:04 AM, Bryan O'Sullivan <bos at serpentine.com>
> wrote:
>>
>> On Tue, Jun 30, 2009 at 9:50 AM, David Leimbach <leimy2k at gmail.com> wrote:
>>>
>>> I actually worry that this will make people think, more incorrectly, that
>>> Monoids are about appending stuff only.
>>
>> I think that adding a graphical operator as a synonym for mappend would
>> actually help to address that, since the magic word "append" would no longer
>> be nearly as common in source code, and that textual name certainly is
>> (unhelpfully) suggestive of a specific semantics.
>
> Yeah the textual name doesn't help one bit.  Much like "return" confuses
> folks in Monads.  However, I think most people learn Haskell in stages where
> ++ is introduced as an append operation *before* they even
> come across the term "Monoid".  I feel that though this may have a lesser degenerative impact on the newbie's ability to learn Monoids, that it still contributes to the confusion a bit.
> Then again, anyone who's had to deal with overloaded operators in any language should learn never to assume anything about overloaded operators...
>
> Dave
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