generalization of maybeToList

Edward Kmett ekmett at gmail.com
Tue Feb 14 21:36:22 CET 2012


The biggest problem is that with each one of these being so short and with
so many useful variations, the concepts struggle to cross the "Fairbairn
threshold".

On Tue, Feb 14, 2012 at 10:47 AM, Jeff Shaw <shawjef3 at msu.edu> wrote:

> I'm all for generalizations! I have a second, very similar function I
> think should be added, but I don't have a good name for it.
>
> maybe mzero id :: MonadPlus m => Maybe (m a) -> m a
>
> Perhaps there is once again an equivalent for Alternative.
>
>
> On 2/14/2012 10:24 AM, Edward Kmett wrote:
>
>> If you are going to add one then the generalization of your
>> generalization to Alternative might be better.
>>
>> maybeA = maybe empty pure
>>
>> On Feb 14, 2012, at 9:55 AM, Jeff Shaw<shawjef3 at msu.edu>  wrote:
>>
>>  I find myself using this function quite a lot. I believe it should be
>>> included in Data.Maybe.
>>>
>>> import Control.Monad
>>>
>>> maybeTo :: (MonadPlus m) =>  Maybe a ->  m a
>>> maybeTo =
>>>    maybe mzero return
>>>
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>>
>
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