Solving Complex Problems with Recursion

When we talk about recursion, there are really two categories of use cases that are quite different from each other. This is particularly true of Clojure. On the one hand, recursion is the primary, low-level way to build loops where other languages would use for, foreach, or with. On the other hand, functional languages such as Clojure generally make it easier for programmers to find elegant, recursive solutions to complex problems.

Tail recursion and functions, or loops, built around recur are suited for problems where the data, input, and output, is essentially linear. Because tail recursive functions can only return one call at a time, they cannot handle problems where it is necessary to follow multiple, forking paths through the data. Clojure provides the tools you need. Using them may require some practice in approaching the problem in a recursive style.

To help build this skill, the remaining exercises in this chapter will be dedicated...