the signature does not allow to mix letters with numbers.

I think we are at cross purposes here. It does allow them to be mixed, you may have any set of letters followed by any set of numbers and ++ will "work". This means that you still have the problem we have been discussing as there is no mapping from 9 to 'a0' but there is a mapping from 'a0' to 9.

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demerphq

_{<Elian> And I do take a kind of perverse pleasure in having an OO assembly language...}