Re: XPattern Specification
* Petr Cimprich <petr@g...> [2005-01-17 11:18]: > Alan Gutierrez wrote: > > > > > > > To match that partuclar end element, with that partucular > > pattern, you only need to update a state machine as the events > > stream by. There's no need to traverse at end element. The > > pattern matches and an event handler takes over the stream. > > > > <foo> > > <bar>one</bar> > > <baz> > > <a><b><c>two</c></b></a> > > </baz> > > <bar>three</bar> > > </foo> > > > > /foo[baz/a/b/c = 'two']/bar[. = 'three'] > > > > I can know that the above pattern matches at the end of the last > > bar, without keeping any nodes at all. > I see. This way could be inconvenient if you have a lot of patterns and > you don't know which of them will be tested in the beginning. Keeping > some info for later evaluation or updating the state machine are > different implementation approaches, XPattern should work for both. > Anyway, I see why you refuse starting with context definition. Let's > work with EBNF then. > BTW, I think XPattern should be a subset of XSLT pattern > (http://www.w3.org/TR/xslt20/#NT-Pattern) rather than XPath expression. Refuse? I don't mean to come across as obstinate. I've been up all night. Perhaps my tone is not what I would want it to be. As far as handling content, I'm not thinking in terms of fetching a nodes out of a tree, but in terms of capturing, and responding to event with event handlers. That's why I think there are two phases, defining the pattern matching langauge, and then, as a second step, trying to come up with a generic expression of capturing and replacing, or inserting. The former is useful as on its own, for XML event handling frameworks. That said, I think that most of XSLT pattern can be matched, by the time all the particpants have passed in the event stream, by a state machine. (It's hard for me to imagine how you would match joins, maybe run two machines to a meeting point? No, need to have axis and literals, only.) I'm sure many of the axis can be preserved. -- Alan Gutierrez - alan@e...
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