qr/^  ab\+cd   \(12\)34$/
   qr/^\s{2}[a-z]{2}\+[a-z]{2}\s{3}\(\d{2}\)\d{2}$/
   qr/^\s+[a-z]+\+[a-z]+\s+\(\d+\)\d+$/
   qr/^\s+\S+\s+\S+$/

##</code><code>##

   $str = '  ab+cd   (12)34';
   $str = quotemeta($str);
   $str =~ s/[a-z]/\[a-z\]/ig;
   $str =~ s/\d/\\d/g;
   $str =~ s/\s+/\\s\+/g;
   $pat = qr/$str/i;
   print "$pat\n";

   Output:
   (?i-xsm:\\s+\\s+[a-z][a-z]\+[a-z][a-z]\\s+\\s+\\s+\(\d\d\)\d\d)

##</code><code>##

   $str = '  ab+cd   (12)34';
   $str = quotemeta($str);
   $str =~ s/\\ / /g;
   $str =~ s/[a-z]/\[a-z\]/ig;
   $str =~ s/\d/\\d/g;
   $str =~ s/\s+/\\s\+/g;
   $pat = qr/$str/i;
   print "$pat\n";

   Output:
   (?i-xsm:\s+[a-z][a-z]\+[a-z][a-z]\s+\(\d\d\)\d\d)