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At 6:58 AM -0700 4/15/04, Jeff Rafter wrote:
>Agreed, well-formednes must be checked. But surely it doesn't need to be
>checked every time a document is parsed (if it is unchanged). I think there
>is definitely room for a parser that can emit SAX events (or something)
>without bogging down in Wellformedness checks. For example, if a document is
>received from a partner, wellformedness is checked, and then pushed into a
>database text field for later processing, there is no need to recheck
>wellformedness.
How do you know no other process or person has modified the field in
the mean time?
> In fact, when it is parsed again later, there is no need to
>do a lot of things-- like check end tags-- if wellformedness is known a
>priori the start tag can be pushed onto a stack, and popped when </ is read.
>Then the "parser" can simply skip the length of the end tag. There are lots
>of savings like this-- duplicate attribute checking for example can be
>costly-- but would be unnecessary if wfness was assumed.
But well-formedness can't be assumed. That's the core of XML.
--
Elliotte Rusty Harold
elharo@metalab.unc.edu
Effective XML (Addison-Wesley, 2003)
http://www.cafeconleche.org/books/effectivexml
http://www.amazon.com/exec/obidos/ISBN%3D0321150406/ref%3Dnosim/cafeaulaitA
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