Chapter 7. Composing Functional Pipelines with Algorithms and Ranges

A frequent source of difficulty for new D users with no background in functional programming is that making sense of the range-based functions from Phobos can be rather daunting, particularly when looking at a long chain of function calls with names that seem as if they come from an alien language. As an old C programmer myself, I still think of hash maps when I see std.algorithm.map, and the C function itoa pops into my head when I see std.range.iota. Until that "eureka" moment where it all falls into place, knowing which functions are used for what, and where to find them in Phobos, can be a challenging task. It's for this reason that some new D programmers tend to avoid ranges and algorithms altogether.

In this chapter, we're going to work on getting past that first hurdle with range-based functions in Phobos. We're going to look into how to use D ranges in a functional style and, in...