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Kevin Jones wrote:
>On Friday 24 December 2004 14:36, Uche Ogbuji wrote:
>>Kevin Jones wrote:
>>Of course XPath is always streamable, if you have no
>>practical limitations (e.g. you're willing to store all
>>node data and implement unbounded look-ahead). When
>>people speak of a "streamable subset", they mean a subset
>>that works practically with most streaming host
>>languages, meaning that these host languages should not
>>have to compromise too much memory or state complexity in
>>order to satisfy the scope of node requests from the
>I was probably being a little brief. I was not intending
>just to comment that XPath was theoretically possible, but
>the assumption you need a subset for this case may be
>wrong. Taking the examples of storing all node data and
>unbounded look-ahead, clearly neither of these are
>requirements of streaming XPath, just features of some way
>of implementing it.
I think I've used some loose language of my own. I tried to be a bit
more scrupulous in my last post:
Does the conceptualization I present at the end of that posting help
clarify the idea of an "XPath subset friendly to SAX processors"?
>I would say that having written/supported one streamable
>subset for a few years they never implemement enough. Some
>of the harder features to implement in a streamable way are
>just the ones that make XPath better than any old pattern
>language, e.g. predicates as expressions.
This is true, somewhat unfortunately.
Uche Ogbuji Fourthought, Inc.
http://uche.ogbuji.net http://4Suite.org http://fourthought.com
Use CSS to display XML - http://www.ibm.com/developerworks/edu/x-dw-x-xmlcss-i.html
Full XML Indexes with Gnosis - http://www.xml.com/pub/a/2004/12/08/py-xml.html
Be humble, not imperial (in design) - http://www.adtmag.com/article.asp?id=10286
UBL 1.0 - http://www-106.ibm.com/developerworks/xml/library/x-think28.html
Use Universal Feed Parser to tame RSS - http://www.ibm.com/developerworks/xml/library/x-tipufp.html
Default and error handling in XSLT lookup tables - http://www.ibm.com/developerworks/xml/library/x-tiplook.html
A survey of XML standards - http://www-106.ibm.com/developerworks/xml/library/x-stand4/
The State of Python-XML in 2004 - http://www.xml.com/pub/a/2004/10/13/py-xml.html