Rustom Mody <rustompm...@gmail.com> writes: <snip> > For a long time the re → dfa transformation went and was taught the laborious > route: > re → nfa-with-ε-transitions → nfa-without-ε-transitions → dfa > > https://en.wikipedia.org/wiki/Thompson's_construction > https://en.wikipedia.org/wiki/Powerset_construction > > Now there is a direct, straightforward method which only becomes available > (thinkable) when we have a null regular expression: > https://drona.csa.iisc.ernet.in/~deepakd/fmcs-06/seminars/presentation.pdf
"Now" seems an odd thing to say since the technique is quite old. It would be better to say that it has been re-discovered. But thanks for the link -- I was unaware of the idea. Unfortunately the material is not well presented there (lower-case phi for the empty set?) but in trying to understand what it was saying I found: https://www.cl.cam.ac.uk/~so294/documents/jfp09.pdf which, in my opinion, does it very much better. <snip> -- Ben. -- https://mail.python.org/mailman/listinfo/python-list
