I'm going over this in my theory class, and I'm curious as to how many people here know what regular expression compilation actually is. I've looked online, and it seems to me that this is a more archaic topic that I thought it was.

So yeah, who here knew before reading this question that a regular expression compile is performed by converting the regex to an epsilon-nondeterministic finite automaton? Who has no clue what that is?

There's a very simple and elegant little regular expression compiler in C that Rob Pike wrote and Brian Kernighan describes in Chapter 1 of O'Reilly's Beautiful Code. It's pretty easy to learn from. Also compiler courses cover it: token types can be defined with regular expressions. So I imagine this knowledge isn't terribly rare.