Nice try, but of course, the issue re. the boundary cases still holds, so the following 
--"a" gives "z"
--"a00" gives "z99"
--"0" gives "9"
--"aa00" gives "zz99"

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give results which aren't reversible. Update: (following comment below)

Yes, you should eat the left-char on underflow, and --"a" => undef and --0 => undef.

I was going to make a point about keeping items in the right order for a sort, but of course zz++ == aaa which screws up that point. Hmmm...
--
Brovnik

In reply to Re: Magical Auto-Decrement by Brovnik
in thread Magical Auto-Decrement by John M. Dlugosz

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