New schema spec

[roddey at us.ibm.com]

>Excellent things. XML was right to simplify SGML and get rid of & and
>exceptions. I hope XSchema will reintroduce both of them, and more.
>

Hmmm. But if schema becomes "thu way" that structural validation is done, then
it won't be some optional part of XML. It will be basically a core part of XML,
in very single implementation out there. So, if XML was right to leave it out to
begin with, why is it a good thing to bring it back now? Have the reasons for
having left it out changed?


>>Just the m to n repetition system means that DFAs wouldn't work anymore right
>
>n{2 to 5} can be replaced by  (n, n, (n, (n, (n)?)?)?)
>
>(n, m){2,5} can be replaced by ((n,m), (n,m), (n,m, (n,m (n,m)?)?)?)
>
>(n|m){2,5} can be replaced by
>    ((n|m), (n|m), (n, ((n, (n|m))
>                                    | (m, (n|m))))
>                            | (m, (n, (n|m))
>                                   | (m, (n|m))))
>
>(n&m){2 to 5} can be replaced by
>     ( ((n, m)| (m,n)),
>       ((n, m)| (m,n)),
>       ( ((n, m)| (m,n)), ( ((n, m)| (m,n)), ((n, m)| (m,n))?)?)? )
>

Well, that's true on the 'just thinking bout it' level. But is it practical?
What if its n{20 to 1000} or something of that nature? That wouldn't be at all
unreasonable from a user's standpoint, but what would be the practical
implications for the data structures used during the creation of the DFA and the
transition table itself?



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