On 5 September 2010 22:40, John Lato <jwl...@gmail.com> wrote: > > Having Pointed is categorically the right thing to do, which is why I argue > for its inclusion. Also, I think it would be prudent to avoid a situation > with the possibility of turning into a rehash of the > Functor/Applicative/Monad mess. > > Are there any good reasons for not including it? Just because we don't have > a use now doesn't mean it might not be useful in the future.
Only reason I can think of: it's a pain to make useless class instances when there is no reason why they can't be combined (since you never make an instance of one without an instance of the other). I _can_ think of a data type that could conceivably be an instance of Pointed but not Applicative: a BloomFilter (though there's not really any point in having a BloomFilter with only one value that I can see, but maybe someone can since there's the singletonB function). -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com IvanMiljenovic.wordpress.com _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
