c:\@Work\Perl\monks>perl -wMstrict -le
"my $string = '/.*u\/ba$/i';
 ;;
 my $rx = eval 'qr' . $string;
 print $rx;
 print 'A: match' if 'u/Ba' =~ $rx;
 ;;
 my $ry = qr{ \A foo $rx }xms;
 print $ry;
 print 'B: match' if 'foolubatU/bA' =~ $ry;
"
(?i-xsm:.*u/ba$)
A: match
(?msx-i: \A foo (?i-xsm:.*u/ba$) )
B: match

[download]

Update: Of course, given that you're dealing with user-supplied data and considering the danger of an injection attack, maybe one should think twice about an eval-based approach.

Give a man a fish:  <%-{-{-{-<

In reply to Re^5: creating qr from existing regex by AnomalousMonk
in thread creating qr from existing regex by Bobert1234

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