New schema spec

roddey at roddey at
Tue May 11 19:38:23 BST 1999

>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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