Summary

Lazy sequences and recursion can be rather challenging. By now, you should know how to safely consume lazy sequences, how to produce them, and how to use them to build tree structures from linear data sources, all without blowing the stack of your runtime.

As we've said before, writing functions to produce your own recursion-based lazy sequences should be something that you reach for only when all the other options won't work. Start with map and filter. If that's not enough, try reduce. Maybe the other forms of recursion will work. If none of those solve your problem, you have lazy sequences, an extremely powerful and efficient tool.

Lazy sequences and recursion always make us think. Being able to write your own lazy sequences will also make you a more enlightened consumer of lazy sequences. In Clojure, this is very valuable because lazy sequences are everywhere. Techniques like the ones we've explored here can also help you start thinking about new...