Arrow provides many datatypes and type classes that reduce significantly complex tasks and provide a standard set of idioms and expressions. In this chapter, we learned how to abstract over null values with Option and to express computations with Either and Try. We created a datatype class, and we also learned about monadic comprehensions and transformations. Last but not least, we used State to represent the application state.

And with this chapter, we reach the final of this journey, but rest assured, this isn't the end of your journey learning functional programming. As we learned in the first chapters, functional programming is all about using functions as building blocks to create complex programs. In the same way, with all the concepts that you learn here, now you can understand and master new, exciting and more powerful ideas. 

Now a new learning journey begins for you.