[eru]

Though going from NFA to explicit DFA isn't always a good idea.

Btw, you might also like looking into the Brzozowski derivative https://en.wikipedia.org/wiki/Brzozowski_derivative which can be used as an alternative way to match regular expressions.

[alphablended]

I think it is also worth mentioning that the site linked at the top uses the antimirov extension to brzozovzki work on regex deivatives.

[lubutu]

To expand, Brzozowski introduced derivatives and Antimirov partial derivatives. Essentially the former correspond to DFAs and the latter to NFAs.

[mikhailfranco]

You could implement the NFA directly with concurrent exploration of all paths:

https://github.com/mike-french/myrex