You can get the paper itself here: "Derivatives of Regular Expressions" Author: Janusz A Brzozowski https://dl.acm.org/doi/10.1145/321239.321249 https://dl.acm.

You can get the paper itself here: "Derivatives of Regular Expressions" Author: Janusz A Brzozowski https://dl.acm.org/doi/10.1145/321239.321249 https://dl.acm.org/doi/10.1145/321239.321249 There's an elegant way to [lazily] get a state machine from a regular expression using this.