xml-dev - re: Obfuscating XML with namespaces

[David Megginson <david@megginson.com>]

Amy Lewis writes:

 > Why are namespace declarations allowed to appear at any level in a
 > document?

People imagined that XML documents might be build out of fragments
from several sources (i.e. separate software components), and that it
would be tricky to co-ordinate prefix information with those
components.  In programming terms, they wanted to move the point of
declaration closes to the point of use.

I was on the other side of this debate (i.e. I agreed with Amy) -- I
thought that allowing NS declarations at every level instead of making
them at the top of the XML document with a PI would make life harder
for the majority of implementors while bringing negligible benefits
for the small minority building systems like the one described in the
last paragraph.  I have written a couple of implementations since, and
found it surprisingly difficult, though not as hard as architectural
forms.

Now that we've had Namespaces for a long time, pretty-much every
serious XML tool supports them, and many major applications (XSLT,
RDF, SOAP, XHTML) use them, it's probably time for the users to pass
judgement who was right -- strictly as an historical footnote, of
course, since it's too late to change anything now.


All the best,


David

-- 
David Megginson                 david@megginson.com
           http://www.megginson.com/