February 20, 2020

A Regular Expression Matcher.

Recursion is a win. This fundamental programming technique almost always leads to smaller, cleaner and more elegant code than the equivalent written with explicit loops, and that is the case here. The idea of peeling off one matching character from the front of the regular expression and from the text, then recursing for the rest, echoes the recursive structure of the traditional factorial or string length examples, but in a much more interesting and useful setting.