Hi Monks!

Please, I need some enlightment about a regex error...

Why am I getting these errors ? I thought \Q and \E where valid escapes for regexen :-( 
Unrecognized escape \Q passed through in regex; marked by <-- HERE 
+in m/\b\Q <-- HERE Renata\E\b/ at -e line 1.
Unrecognized escape \E passed through in regex; marked by <-- HERE 
+in m/\b\QRenata\E <-- HERE \b/ at -e line 1.

[download]
The $regexp is retrieved from a DB, and came from an user (the interface appended \Q...\E before storing it in the DB) The offending code snippet is this: 
# ...
print STDERR "/$regexp/\n";
$throw_away = ($window =~ /$regexp/ism) ? 'TRUE' : 'FALSE';
# ...

[download]
And the "STDERR" output before the error is: 
/\b\QRenata\E\b/

[download]

Thanks in Advance :-)


Update:Maybe I wasn't clear about a point: the regexes come from a DB, and in DB they already had \b...\b, and now some (few) of them have \b\Q...\E\b there. Is isn't my script that is messing with them...

last update:Thanks ikegami-san (who explained the point about \Q...\E in interpolations), and others who helped. I'm accepting more suggestions, but for now, as the regexes are "simple" (whatever that means :-)), I'll go with quotemeta()'ing whatever is inside \Q...\E (the text in question has no "\" so I wont fall in the \\Quux trap :-))

-- 6x9=42

In reply to Unrecognized escape \Q passed through in regex by Articuno

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.