It's interesting that it's using Laurikari's algorithm- I looked at the 2000 paper years ago and could not get a working algorithm out of it. Eventually I foun

It's interesting that it's using Laurikari's algorithm- I looked at the 2000 paper years ago and could not get a working algorithm out of it. Eventually I found another way to do this that I use for JOE's regular expression library. So now I'm curious which one is faster... https://sourceforge.net/p/joe-editor/mercurial/ci/default/tree/docs/hacking.md#regular-expressions https://sourceforge.net/p/joe-editor/mercurial/ci/default/tr... It uses a variant a Thompson's matcher, see: https://swtch.com/~rsc/regexp/regexp1.html https://swtch.com/~rsc/regexp/regexp1.html "However, Thompson-style algorithms can be adapted to track submatch boundaries without giving up efficient performance. The Eighth Edition Unix regexp(3) library implemented such an algorithm as early as 1985, though as explained below, it was not very widely used or even noticed. " So in JOE's matcher, when simulating the NFA with the multithreaded machine, each succeeding thread will correspond to one of the sub-match possibilities. Augment this machine to keep the ones you want (the ones with the longest matching strings starting from the left usually).