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Elliotte Harold wrote:
> I'm curious. Have any parser implementers built a dynamic cache of
> preverified names? Did it help any? Even if it in the general case it
> proves to be no faster than repeatedly checking the same names, it might
> still be useful to preload a cache of especially common names before
> parsing a lot of documents.
Microsoft is using this technique in .NET where a vocabulary is known a
priori, e.g. in XSLT implementation - they eagerly preload all XSLT and
XML keywords into a nametable at the beginning. Saxon is doing the same.
> Another possible optimization: you don't need to verify end-tags, just
> check that it matches the start-tag, which you have to do anyway. I'm
> almost certain some, perhaps most or all, parsers are doing this already.
At least .NET's XmlTextReader employs it -
http://dotnet.di.unipi.it/Content/sscli/docs/doxygen/fx/bcl/xmltextreader_8cs-source.html,
line 742 (that's sscli sources - officially it's not .NET sources, but
frankly speaking they are almost always very-very close to .NET 1.0).
--
Oleg Tkachenko
http://blog.tkachenko.com
Multiconn Technologies, Israel
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