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