About node references

  EXSLTers,

  There've been useful discussions around node references objects.
Let me summarize those, and point out open points.

  1/ I still fail to see use cases that node refs would help solving,
if we had sequence refs (or nested sequences.)  If node refs are plain
strings, I understand they could be added to an XML tree, but I can't
see what that could solve that nested sequences couldn't.

  2/ Node refs as plain strings vs. undefined item types, regarding
resource management (I think item()+ wouldn't be so useful anyway, as
it would atomize if added to another sequence, so I think this is
really xs:string vs. item().)  I think having a string could be
challenging regarding resource management: how could a processor
decide to discard a document if we can have string references to its
nodes?

  Of course we want to specify an extension, but I think good
specifications do take pertinent implementation concerns into account
to be sure the functionality is implementable in a reasonable way...
And I think it could be impossible to implement on processors that use
their own source language's garbage collection to manage the trees's
object life time, or at least to reduce optimization opportunities to
discard unused trees or to stream processing.

  Any thought from implementers?

  Regards,

-- 
Florent Georges
http://www.fgeorges.org/