On 5 September 2010 22:40, John Lato
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.Miljenovic@gmail.com IvanMiljenovic.wordpress.com