Don’t fear the Monad
Luigi Antonini
393

Always great to see functional programming blogs! :)

Monad is too strong an abstraction for most of these examples though. In the case of getFullName2, there is no dependency betweengetFirstName(user) and getLastName(user) so you can simply use Applicative instead:

Applicative[Option].map2(getFirstName(user), getLastName(user))((firstName, lastName) => s"$firstName:$lastName")

This is less a problem for Option, but when it comes to Future, using Applicative gives a tangible difference in performance (for instance in concatWebPages2) . Applicative allows the Futures to fire off in parallel, as opposed to sequentially, because there is no dependency between each computation.

Additionally, if you had many Future[Option[T]] stacks that are independent computations, Applicative[Future].compose[Option] will allow you to compose them easily without nested flatMaps.

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