http://www.perlmonks.org?node_id=793613


in reply to Find what characters never appear

I don't know if this will work for you, but in the past when I've had similar challenges, I've used a string of characters as my separator pattern instead of a single character. For example, #|+|#. The odds of a pattern occuring naturally are less than those of a single character.

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It's all fine and dandy until someone has to look at the code.