From: David Menendez <dave@zednenem.com>
Subject: Re: Functor => Pointed => Applicative => Monad
To: Isaac Dupree <ml@isaac.cedarswampstudios.org>
Cc: libraries@haskell.org
Message-ID:
       <AANLkTinkqQXYTN6ATqGawbdeVvtfq_6z51sADN8i_O8P@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

On Mon, Nov 29, 2010 at 11:26 AM, Isaac Dupree
<ml@isaac.cedarswampstudios.org> wrote:
> On 11/29/10 03:39, John Smith wrote:
>>
>> Is there any intention to reorganise the standard class hierarchy,
>> arranging them logically instead of in order of invention? I plagiarised
>> the following example from
>> http://stackoverflow.com/questions/1634911/can-liftm-differ-from-lifta
>> and Trac:
>>
>> class Functor f where
>> map :: (a -> b) -> f a -> f b
>>
>> class Functor f => Pointed f where
>> pure :: a -> f a
>
> Is it useful to have Pointed non-Functors?

Is Pointed useful at all? The last time this discussion came up, I
asked for algorithms which were generic over pointed functors (in the
same way that traverse is generic over applicative functors) and no
one could think of any.