Haskell Cookbook

How to do it...

1. Create a new project working-with-applicative with the simple Stack template:

        stack new working-with-applicative simple

2. Open src/Main.hs and add the following imports after the initial module definition. The Applicative type class is defined in the module Control.Applicative:

        import Data.Functor        import Control.Applicative

3. We will use two operators, Functor application <$> (synonym for fmap) and Applicative application <*>. The Applicative function <*> is defined as <*> :: f (a -> b) -> f a -> f b. It takes a data type where values are functions of type (a -> b) and applies to a data type with values of type a, and gets back the data type with values of type b. In the first example, we will use a list: 

 -- Mapping ...