Magical journey through regex engine internals

How the computer knows that `^\w+\d$` matches "Java8" but "PH15"? It's magic that allows it to match patterns with strings, right? Yes, and we, geeks love learning how such magic works! Join me in a highly technical journey through the regex engine. From ancient scripts explaining theory (automata and regular languages), through thickets of various regex implementation to the cave of the regex performance. We'll spicy up the adventure by falling into a trap of exponentially slow regex that will crash a real app. Finally we'll analyse regex traps that Stackoverflow and Cloudflare set for themselves. It's a geeky talk and you'll learn geeky stuff: how the language of regular expressions is implemented. But it'll be not in vain: you'll be able to optimise a regex and prevent your app from being killed by a badly-crafted one.