Let's enhance our Functor from few episodes ago !
Let's learn about Applicative which extends what a Functor can do.
Now we can build more complex things with the structures we know !
Keep in mind that all the rules from Functor are still true.
With Applicative we open the possibility to work with several “Boxes”. With Functor only, it wouldn't be possible to combine and compose them together. But with Applicative, we can !
With Functor only, if we have
F[A => B] and
map alone, we wouldn't be able to combine them together. But with the
applicate method (also simply called
ap), we can !
We are getting closer to