Walking the DOM (was: XML APIs)

Sean Mc Grath digitome at iol.ie
Wed Nov 4 09:45:35 GMT 1998

[Paul Prescod]
>But the persistent ancillary-info trick (i.e. "object database") keeps
>only the data it needs to in memory. If it requires lots of swapping, that
>slows things down, but the algorithm works nevertheless. If you blow your
>stack, you blow your stack, and there is no database in the world that
>will help you.
>Depending on the algorithm, walking an object database tree for a really
>huge file may be faster than parsing it and event-processing it. It
>depends on how many nodes you are actually processing, and how much
>ancillary info you must keep around to solve the problem you need to
In my experience, there is a strong "principle of locality" in
XML/SGML processing. I find I can get by quite happily with
mini-tree structures harvested at suitable points from
a larger document processed event-style. In my
Python toolkit for SGML/XML processing I added support
for sparse tree building some time ago and I find myself
using it more and more.

This is certainly far easier to do that implement virtual
tree access with swapping to disk etc. You don't need
no object database either:-)


The "Swiss Army Laser Beam" of programming languages

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