Proposal: Add Alternative adapter to Data.Monoid

[David Feuer]

We might be able to put it in Data.Monoid. I though I had some kind of
weird problem with that, but I don't remember.

On Fri, Oct 31, 2014 at 12:50 PM, Edward Kmett <ekmett at gmail.com> wrote:

> Actually that feels like a very wrong place for it.
>
> It may wind up having to go there, but I do care. =P
>
> -Edward
>
>
>
>
> On Fri, Oct 31, 2014 at 12:49 PM, David Feuer <david.feuer at gmail.com>
> wrote:
>
>> And one more change: this can't go in Data.Monoid; it needs to go in
>> Control.Applicative. I can't imagine anyone will care.
>> On Oct 31, 2014 12:47 PM, "Edward Kmett" <ekmett at gmail.com> wrote:
>>
>>> The one change I'd offer is this:
>>>
>>> instance Alternative f => Monoid (Alt f a) where
>>>   mempty = Alt empty
>>> *  mappend = coerce ((<|>) :: f a -> f a -> f a)*
>>>
>>> That way it doesn't eta-expand (<|>).
>>>
>>> -Edward
>>>
>>>
>>> On Fri, Oct 31, 2014 at 12:35 PM, Carl Howells <chowells79 at gmail.com>
>>> wrote:
>>>
>>>> Oh right.  This is what I joined this list to propose in the first
>>>> place, then forgot about.  Uh, do I get a vote? If I have one, I'm
>>>> obviously +1 on the idea.
>>>>
>>>> On Thu, Oct 30, 2014 at 10:54 AM, Oliver Charles <ollie at ocharles.org.uk>
>>>> wrote:
>>>> > David Feuer <david.feuer at gmail.com> writes:
>>>> >
>>>> >> I found myself needing this type in my current overhaul of
>>>> Data.Foldable,
>>>> >> but it seems to be generally useful:
>>>> >
>>>> > +1, I can see myself wanting to reach for this.
>>>> >
>>>> > -- ocharles
>>>> > _______________________________________________
>>>> > Libraries mailing list
>>>> > Libraries at haskell.org
>>>> > http://www.haskell.org/mailman/listinfo/libraries
>>>>
>>>
>>>
>
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