$String =~ /(??{substr($RegEx,1,-2)})/;

##</code><code>##

($x,$s,$m) = split(/\//,$RegEx);
sub p {print "Match: ",$&||"none"," Pre: ",$`||"none"," Post: ",$'||"none","\n"}
if ($m eq 'i') {$String =~ /$s/i;p}
if ($m eq 'm') {$String =~ /$s/m;p}
if ($m eq 's') {$String =~ /$s/s;p}
if ($m eq 'x') {$String =~ /$s/x;p}
if ($m eq 'o') {$String =~ /$s/o;p}
if ($m eq 'im') {$String =~ /$s/im;p}
if ($m eq 'is') {$String =~ /$s/is;p}
if ($m eq 'ix') {$String =~ /$s/ix;p}
if ($m eq 'io') {$String =~ /$s/io;p}
if ($m eq 'mis') {$String =~ /$s/mips;p}
if ($m eq 'mix') {$String =~ /$s/mix;p}
if ($m eq 'mio') {$String =~ /$s/mio;p}
if ($m eq 'smix') {$String =~ /$s/smix;p}
if ($m eq 'smio') {$String =~ /$s/smio;p}
if ($m eq 'xsmio') {$String =~ /$s/xsmio;p}