Summary

Diving into the world of functional programming in C# has been a stimulating journey, and we’re only just getting started. In this chapter, we explored the pivotal concepts of pure functions and side effects and their respective roles in writing cleaner, more predictable, and maintainable code. Let’s reinforce the knowledge we’ve gained and map out the course moving forward.

Pure functions stand as a beacon of certainty in the unpredictable universe of software. They have a clear-cut contract – the same input always yields the same output, and they remain uninvolved with the state outside their scope. This simplicity makes them predictable, easy to test, and more amenable to parallelization and optimization.

However, the real world is filled with side effects – reading and writing to a database, calling an API, modifying a global variable – the list goes on. Side effects are inevitable, but when uncontrolled, they can unleash...