Creating concurrent functions

Broadly speaking, there are two types of concurrency that we will be looking at in this chapter. We can call them intra-concurrency and extra-concurrency:

• Intra-concurrency is about creating functions that are implemented concurrently internal to each function. For example, in Chapter 6, we saw various functions such as Filter, Map, and FMap that lend themselves to a concurrent implementation. That will be the focus of this section. Notably, they can be used in conjunction with each other so that we achieve concurrency at multiple steps in our algorithm, and we can even decide on the level of concurrency required for each step individually.
• Extra-concurrency is about chaining together functions using Go's built-in concurrency features: channels and goroutines. This is explored later in the chapter.

Why are many of the fundamental building blocks of functional programming good candidates for concurrency? Well, first and foremost...