I saw this post on Roman Numerals in Clojure:
This is the sort of little programming problem that can stop useful work dead in its tracks. Here’s my shot at the problem. I think it reads better in that the recursion just deals with the numbers and the Roman numeral strings are mapped latter. It’s also a bit more efficient in the way it tests against the Roman “bases” (as I call them). There’s no need to retest against a high base once your interim value has gone below that mark. In any case, my version is quite a bit faster than the other solution in my micro-benchmarks.