From: MenTaLguY Date: 2007-04-11T04:14:58+09:00 Subject: Re: Slow ruby regexes On Wed, 11 Apr 2007 03:56:28 +0900, "Robert Dober" wrote: > The bad news is that the power of regexs will just not let you escape > with bad design all the time, so knowing a lot about regexes is a > necessary thing to use them well. No, the bad news is that the bad design of most "regex" implementations will not let you escape with using "regexes" as if they were true regular expressions; knowing a lot about the implementation of the regex engine is a necessary thing to use them well. > But you are right of course that Ruby's current Regex implementation > is not state of the art, useful, very useful nevertheless. NFAs were state-of-the-art in the 1960s. Backreferences are nice, but in other respects we've actually regressed since then. I'm not suggesting we abandon backreferences and so forth (which are useful sometimes), but rather that NFAs should be used for evaluating the majority of "regexes" which don't use non-regular features. -mental