I was going to answer something like that, but forgot all about it. In the meantime, I've read (once again) some parts of CGI.pm, and found these interesting regexes:

         $toencode =~ s{&}{&}gso;
         $toencode =~ s{<}{&lt;}gso;
         $toencode =~ s{>}{&gt;}gso;
         $toencode =~ s{"}{&quot;}gso;
...
                $toencode =~ s{'}{&#39;}gso;
                $toencode =~ s{\x8b}{&#139;}gso;
                $toencode =~ s{\x9b}{&#155;}gso;
...
                     $toencode =~ s{\012}{&#10;}gso;
                     $toencode =~ s{\015}{&#13;}gso;
[download]

That's at least 9 uses of /o with no variable interpolation in the pattern.

But CGI also doesn't use strict, has no spaces after commas, uses C-style for-loops where lists where more efficient and better readable, assumes that the IP address "0" equals "127.0.0.1", has ugly #-laden comments, etc... So is the use of /o really more efficient when no variable interpolation is used, or is this yet another strange thing in CGI.pm. (Excuse me for being so negative about CGI.pm, but having read it, I prefer my own set of functions even more.)

44696420796F7520732F2F2F65206F
7220756E7061636B3F202F6D736720
6D6521203A29202D2D204A75657264

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.