Re: [xml-dev] XPath and XPattern (was Re: [xml-dev] More on taming SAX)

From
Karl Waclawek <>
To
Uche Ogbuji <>
Date
2004-12-24T05:36:21Z
ID
<>
Thread
Re: [xml-dev] XPath and XPattern (was Re: [xml-dev] More on taming SAX)
Uche Ogbuji wrote:

>>There's also the question of context -- would the only context be the
>>stack, or do people hope to have access to left siblings as well?
> 
> 
> I'd say only the parent stack, or shallow but very wide documents become
> resource hogs.  An extension mechanism could allow implementations to
> support sibling access, or perhaps that would be a matter of conformance
> levels (a la DOM or XAPI).

Why not leave this to the application to decide.
Just provide a hook for accessing context, but
don't make a decision what to provide.
Providing these hooks just on the parent stack
should be sufficient, because at the parent level
one can aggregate context as needed.

I have found that even transformations that
require some backward navigation can be done
using a streaming approach.
Even for a document where the first line of output
needs to process the last line of input you often do
not need to build a complete DOM.

Karl