The perl regex algorithm/engine is neither DFA nor NFA.
Yeah, Erez, it's good to point this out (++). By strict standards, it is true that the Perl regex engine is neither NFA, nor DFA. In fact, the Perl regex engine is not even doing regular expressions (at least not in the sense of academic regular expressions, as they were defined some 70 years ago). Perl is using highly irregular expressions. And even more so with Perl 6 (which explicitly states it is using the "regex" term, rather than "regular expressions", because it is even further away from the original regular expressions, even if it broadly works according to the same principles).

Yet, if we are to accept the broader sense of regexes as usually meant nowadays in common programming languages, and more broadly in practical computing, and coming back to the specific question in the original post, I think it can be said that the Perl regex engine is broadly much closer to NFA than to DFA. That's what I meant in my previous post, only that, I did not mean to go in the details of theoretical distinctions which are probably very important for research but of relatively little significance for practical computing.

In reply to Re^2: Is RegEx in Perl not NFA anymore? by Laurent_R
in thread Is RegEx in Perl not NFA anymore? by redbull2012

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