Clojurians Log v2

At the end of http://funcool.github.io/cats/latest/#applicative there is :

(require '[cats.monad.maybe :as maybe])

(pure maybe/maybe-monad 5)
;; => #<Just 5>

Is it maybe now? : https://github.com/funcool/cats/blob/master/src/cats/monad/maybe.cljc#L304

Also, unrelated but I asked a question there : http://stackoverflow.com/q/35770498/1327651

also, why do these don't work, given that (just [1 2 3]) is a wrapped value ?

(fmap inc (just [1 2 3]))
(fmap inc (map just [1 2 3]))

@nha: i suspect that docs are out of sync, i believe it was renamed to maybe-context

Probably a doc thing, yes.

I don't see maybe-context though

@nha: it's cats.monad.maybe/context, sorry https://github.com/funcool/cats/blob/master/src/cats/monad/maybe.cljc#L170

Ah thanks :simple_smile:

and about the mapping

take into account that fmap "peels" one layer of monadic context

so in the example

(fmap inc (just [1 2 3]))

will try to apply inc to [1 2 3]

thus failing

ah I see. (inc [ 1 2 3])

ok :simple_smile:

you can combine maybe and sequence functors

and map over nested vectors inside maybe or viceversa

although having many layers can get hairy

(fmap #(map inc %) (just [1 2 3])) may be simpler

Right thanks :simple_smile:

just out of curiosity (as I think I remember you do scala), is there an equivalent of their flatten that resolves async values (note : I don't do scala so I may be wrong about that)

you mean for example transforming Future[A] into A?

in Clojure you can dereference futures and the thread will block until available (timeout is optional)

(deref some-future)