Dave,

How much effect would limiting nested parentheses to two and {##} numbers to two digits have on that CPU resource hogging? Would there be an effective way of mitigating against this?

This is the sort of helpful tip I'm looking for. It does little good to say ever so meaningfully: "You would be ill-advised to do this...." I'm looking for rational support to such a statement; as in, why is it inadvisable.

Once potential pitfalls are identified, only then can one hope to address them. And I do hope to make things safer, albeit, not completely foolproof.

I'm reminded of a setting provided to server administrators in shorewall's firewall management tools....something like "ADMIN_IS_ABSENT_MINDED = 1". Hah! It was supposed to keep the current connection open in case of a firewall restart with ill-advised settings that might have inadvertently locked even the admin out! It's simply never possible to make something completely foolproof, and I don't intend to try. But I do want to make it, at the very least, secure from hacker penetration. CPU resources is one thing. Gaining server admin privileges through a security hole is another.