Eric Kidd wrote:

I've been reading through ZPublisher/HTTPRequest.py, and I noticed several uses of regex.compile. Oddly enough, the result is thrown out after one use and recomputed later.

Where do you see this? I don't see any case of this. Note that most usages are like: end_of_header_search=regex.compile('</head>',regex.casefold).search Here we retain the regular expression's search method. This effectively keeps the regex around too. By only keeping the search method (and not the regex), it's easy to see that the regex usage is thread safe. We also create a regex when gathering form input. We may use it several times before throwing it away. We make a new regex on each call for thread safety reasons.

Isn't regex.compile an expensive operation?

Somewhat. It's not that big a deal. I keep them around most of the time.

Should the results of regex.compile by stored between uses?

Absolutely. But one has to be careful about thread safety. Using a regex search and group methods together can cause race conditions. Jim -- Jim Fulton mailto:jim@digicool.com Technical Director (888) 344-4332 Python Powered! Digital Creations http://www.digicool.com http://www.python.org Under US Code Title 47, Sec.227(b)(1)(C), Sec.227(a)(2)(B) This email address may not be added to any commercial mail list with out my permission. Violation of my privacy with advertising or SPAM will result in a suit for a MINIMUM of $500 damages/incident, $1500 for repeats.