+use constant _QR_TYPES => {
+ '' => sub { qr{$_[0]} },
+ x => sub { qr{$_[0]}x },
+ i => sub { qr{$_[0]}i },
+ s => sub { qr{$_[0]}s },
+ m => sub { qr{$_[0]}m },
+ ix => sub { qr{$_[0]}ix },
+ sx => sub { qr{$_[0]}sx },
+ mx => sub { qr{$_[0]}mx },
+ si => sub { qr{$_[0]}si },
+ mi => sub { qr{$_[0]}mi },
+ ms => sub { qr{$_[0]}sm },
+ six => sub { qr{$_[0]}six },
+ mix => sub { qr{$_[0]}mix },
+ msx => sub { qr{$_[0]}msx },
+ msi => sub { qr{$_[0]}msi },
+ msix => sub { qr{$_[0]}msix },
+};
+