Where has the map method on Optional moved?

[Sam Pullara]

I've never been comfortable with this. I'm glad Jed is calling it out.
Can we make Optional first class or remove it?

Sam

On Mon, Feb 25, 2013 at 9:12 PM, Jed Wesley-Smith <jed at wesleysmith.io> wrote:
> Hi Paul,
>
> You don't get a choice, it is a (or forms a) monad, you just removed
> the useful methods (map/flatMap aka fmap/bind). This leaves clients to
> implement them (or the functionality) in an ad-hoc and possibly buggy
> form themselves.
>
> It is a monad if there exists some pair of functions:
>
> A -> Option<A>
> Option<A> -> (A -> Option<B>) -> Option<B>
>
> The first is Optional.of, the second is currently:
>
> Optional<A> a = …
> Optional<B> b = …
> Function<A, Optional<B> f = …
> if (a.isPresent) {
>   b = f.apply(a.get());
> } else {
>   b = Optional.empty();
> }
>
> rather than:
>
> Optional<A> a = …
> Function<A, Optional<B> f = …
> final Optional<B> b = a.flatMap(f);
>
> cheers,
> jed.
>
> On 26 February 2013 00:12, Paul Sandoz <paul.sandoz at oracle.com> wrote:
>> Hi Dhananjay,
>>
>> It is not missing it was removed.
>>
>> java.util.Optional has a narrower scope that optional things in other languages. We are not trying to shoe-horn in an option monad.
>>
>> Paul.
>>
>> On Feb 23, 2013, at 12:27 AM, Dhananjay Nene <dhananjay.nene at gmail.com> wrote:
>>
>>> It seemed to be there on the Optional class in b61 but is missing now. Is
>>> there some way to run map/flatMap operations on an Optional?
>>>
>>> Thanks
>>> Dhananjay
>>>
>>
>>
>