in reply to Re: Compiling Regular Expressions
in thread Compiling Regular Expressions
A few comments... (Monks, correct me if I'm right)
You are correct that study is the opposite of what the OP wants, but only in your second point, in that it works on the scalar to be matched, and not on the regex itself. I have a feeling that your first point - that it 'takes more time' - is a mis-interpretation of the documentation: study takes extra time up-front to study the scalar in question, if you want to do lots of different regex's on it. Depending on your scalar and your regex's, peforming the study may save time on the regex's because you've already analyzed the heck out of that scalar.
A possible scenario when this is useful: Let's say your scalar is a paragraph of text. You plan to run all sorts of matches on this text, to get some sort of statistics on it ('foo' was mentioned twice, 'bar' mentioned once, in the word 'barfly', 'um' appeared 3 times, always followed by '...', etc.). Thus you want to study() the same paragraph, to (possibly) save time on all those different regex's you're going to throw at it...
This is the opposite of what the OP wants, since s/he wants to use the same regex on many different scalars... In this case, I think the previous comments are right on - the regex will be compiled only once if it contains no variable interpolation (i.e. /pattern/), so there's no cause for concern, and using the '/o' operator will force the pattern to be compiled only once if it is in a variable (i.e. /$pattern/o), with the caveat that you cannot change the value of $pattern (well, of course you can, but perl won't notice, and will continue to perform the regex with the value of $pattern when the '/o' was used...)
Hope this helps (and is accurate)...