One of the issues that we'll need to deal with at some point is spelling errors. Especially when you're trying to work with raw text, spelling errors can throw a wrench in the works.

At one time, spell checkers were major pieces of software with lots of optimizations to run in the constrained environments that were once everyday desktops. Now, that's not the case. Peter Norvig has published a piece on the Internet titled How to Write a Spelling Corrector (http://norvig.com/spell-correct.html). This shows how to take some text that is assumed to be spelled correctly and generate a spell checker built on it. He included a 21-line implementation in Python.

For this recipe, we'll convert the Python code to Clojure. Our version will be longer, but less dense. We can certainly implement it more concisely than we will do it, but it will be helpful for our explanation to break it out more.