[Phoenix] Constraints on XML documents to work with Yulup

[Andreas Wuest]

Hi

Summing up the previously mentioned problems, an XML source document and 
its associated XSLT have to fulfil the following constraints to 
currently work with Yulup:

XML source:
  (1) IFF namespace(s) are used in a XML document, then all elements 
MUST be prefixed.
  (2) IFF namespace(s) are used in a XML document, then all namespace 
declarations MUST occur at the document root element.
  (3) IFF namespace(s) are used in a XML document, then namespace 
prefixes MUST NOT be overridden in a descendant element (but this is 
ruled out by constraint number 2 anyway).

XSLT:
  (4) Namespace prefix tuples (i.e. {prefix,namespace}) used in the XSLT 
stylesheet MUST be equal to those used in the XML source.

Note that you can happily use XML documents which don't make use of 
namespaces though.

Note also that we might be able to drop constraint number (1) by 
introducing custom prefixes for all elements.

Note also that we might be able to drop constraint number (2) by first 
gathering all namespace information contained in that document, but this 
would be mutually exclusive with solving constraint number (3).

Note also that we might be able to drop constraint number (4) by copying 
all namespace declarations used in the XSLT stylesheet to an 
intermediate copy of the XML source.

And last but not least, note that implementing namespace-unawareness 
resolves all of those 4 constraints (although at the cost of introducing 
new problems).

-- 
Kind regards,
Andi