The speed differences are small enough to be irrelevant for almost all real world situations. The important difference is that qr// is a clear and fairly obvious modifier, which /o does something totally bizarre, i.e. the first time a regex with /o runs it will do one thing and every other time it will do something different. This frequently wreaks havoc in persistent environments like mod_perl where people forget that /o regexes will not get reset after their script finishes.

In reply to Re: Re: Never by perrin
in thread Never-to-use Perl features? by Juerd

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