in reply to Re: qr// hidden risks
in thread Risks in the oblivious use of qr//

but isn't this sort of obvious?

Well, this is the whole point. It could not be ovbious for everyone. What is not clearly explained is that qr// will unset the modifiers that we haven't explicitly set.

I didn't mean to rewrite the Bible :), but just to warn against something that may not be immediately perceived. The problem only exists when you embed a pre-compiled regex within a larger expression.

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  • Comment on Re: Re: Risks in the oblivious use of qr//

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Re: Re: Re: qr// hidden risks
by hossman (Prior) on Aug 10, 2003 at 17:10 UTC

    Well, people should read documentation. If you see "qr" and don't understand what it does, the first thing you should do is read the docs -- don't just assume you know how it works.

    From perldoc -f qr 

           qr/STRING/

       qx/STRING/

       qw/STRING/
               Generalized quotes.  See the Regexp Quote-Like
               Operators entry in the perlop manpage.

    From perldoc perlop 

           qr/STRING/imosx
               This operators quotes--and compiles--its STRING as
               a regular expression.  STRING is interpolated the
               same way as PATTERN in `m/PATTERN/'.  If "'" is
               used as the delimiter, no interpolation is done.
               Returns a Perl value which may be used instead of
               the corresponding `/STRING/imosx' expression.

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