> I do not find it difficult to imagine a grammar that can
> specify these constraints; using the set-notation formalisms
> common in discussions of automata, it's relatively
> straightforward (handling the various gregorian exceptions
> gets increasingly difficult and verbose as one grows more and
> more precise, but it is not inherently beyond the scope of a
> grammar ... is it?).
I've no idea what the theoretical limits of what you can do with a grammar
are (I don't even know what the accepted definition of "grammar" is), but I
think I have a feel for the practical limits of when grammar ceases to be
the most convenient way of stating the rules. I see people sometimes doing
things with regular expressions that in my view are well beyond that limit.
Why stretch one technology to its limits when you've crossed into a domain
where other technologies do it better?
Michael Kay
