Haskell in Depth

5 Monads as practical functionality providers

This chapter covers

• A pragmatic approach to monads and the functionality they provide
• Accessing configuration, writing logs, and maintaining state with monads
• Exploiting various approaches to mutability in the IO and ST monads

Monads can be seen and taught from many perspectives. The mathematics behind them is just one perspective, and we’ll ignore it by focusing on the functionality monads provide. Monads can simplify our code by promoting coherent abstraction and guarantees of the uniformity of the code. In this chapter, we’ll talk about using monads in practice. We’ll see how they help us to implement difficult algorithms clearly and correctly and to write short and concise code while maintaining ...