To get over that you must encapsulate Sigma, so that a condition like that does not arise. If you convert to a smaller subset and then use out of band data that will be safe (example - convert to hex and join with spaces). Also safe is escaping - because that's basically just creating a wide charset, which is a larger Sigma, enabling data out of the UTF or ASCII sigma. This is possibly faster, and more memory efficient.

If you join("\\",map { quotemeta($_) } @array); you will get a safe value, because quotemeta ensures that a single \ will never appear in the values.

-nuffin
zz zZ Z Z #!perl