Re: A Friday Regex Head Scratcher
"Jon Earle" <[email protected]>
| Newsgroups | gmane.user-groups.linux.ottawa.general |
|---|---|
| Message-ID | <[email protected]> |
Yanick Champoux wrote: > Whereas the use of $1, $2, > etc, will only impart a performance penalty to the regexes in which they > are used[*], using $& will trigger that penalty for *all* regexes in the > program (simply because there's no way to know a priori which regex we > want to capture the content of). > > Now, this being said, that delta of performance is typically fairly > small. For little scripts, you'll have to squint real hard to see it. Oh, I see... for every program (ie: .pl file), a single $& affects every regex that could potentially be encountered in that program, whereas $1 affects only the specific regex in which it's used, in which case, Dave's suggestion of using $1 optimizes performance of the entire program (or rather, prevents performance degradation of the entire program). Is that correct? > Excellent. I was half afraid you'd take a look at the regex, turn > green, and immediately proceed to format your hard-drive. :-) Well, I admit, on Fri afternoon, I tried to decipher it and closed it in fear. :) A fresh look on Monday made it all come together. -- OCLUG general discussion list [email protected] http://oclug.on.ca/mailman/listinfo/oclug