After reading lesson 30, you’ll be able to
You’ve just finished learning about two important type classes, Functor and Applicative. Each has allowed you to perform increasingly powerful computations within a context such as Maybe or IO. Functor allows you to change individual values in a context:
GHCi> (+ 2) <$> Just 3 Just 5
Applicative increases your power by enabling you to use partial application in a context. This, in turn, allows you to use multiple arguments in a context:
GHCi> pure (+) <*> Just 3 <*> Just 2 Just 5
In this lesson, ...