Reading Regex: How to Visualize What Your Pattern Actually Does

I can read most programming languages at a glance. Regex I have to decode character by character. This isn't a personal failing. It's a consequence of regex syntax being maximally dense. Every character is either a literal, a metacharacter, or a quantifier, and context determines which interpretation applies. Visualization transforms regex from a string of symbols into a diagram of states and transitions. Instead of parsing (?<=@)\w+(?=\.\w+$) mentally, you see a flowchart: lookbehind for @, then one or more word characters, then lookahead for dot-word-end. Regex as a state machine Every regular expression is equivalent to a finite automaton, a state machine with states and transitions. The input string is consumed character by character, each character triggering a transition. If the machine reaches an accepting state, the string matches. For the pattern ab+c : State 0: Start. On 'a', go to State 1. State 1: On 'b', go to State 2. State 2: On 'b', stay at State 2. On 'c', go to State