New schema spec

roddey at roddey at
Mon May 10 19:40:23 BST 1999

I am interested in some comments on the new Schema spec. In particular, what are
people's thoughts about the fact that the AND connector has been reintroduced
and that SEQ,ALT,AND blocks now support an optional min/max repetition count? Is
there any way that such a system could be reasonably confirmed to be
non-ambigious (and by reasonable I mean very fast and small amount of code.)
And, given that, is there any way that it could be validated against in some
less than exhaustive search way?

The scenarios that scare me are say you have a node that can take 1 to 5 of some
complex scenario, and each of those did similar things. How can you guarantee
that if you only ate 2 of the top level that something down stream would not
have matched better? Or if you ate only one at any one level that that wouldn't
be a suboptimal match than if you had eat 3 of them?

I'd be interested to hear from some our more pointy headed breathren (just
kidding of course :-) about the theoretical implications of such a system. It
seems obvious that DFAs, and the very fast and compact mechanisms they
represent, would go out the door immediately, right? And that would remain true
even if the AND connector was left out. Just the m to n repetition system means
that DFAs wouldn't work anymore right?

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