RE: [xml-dev] Nested Documents (was: XML 2.0)

["Michael Kay" <mike@saxonica.com>]

> 
> How about adding something to the xml prolog that must be 
> present when the document contains multiple root elements:
> 
> <?xml version="1.0" multiple-root-elements="yes"?>
> 
> Make it like non-UTF-8 or UTF-16 encodings - if it's not 
> present the document must have a single root element, if you 
> do want multiple root elements then you must specify it in the prolog.
> 
> Seems straightforward enough...

Except you lose the nice simplification that document entities and external
parsed entities become indistinguishable. The aim of this exercise is to
simplify things and remove restrictions, not to add new rules.

Also, serializers (e.g. XSLT serializers) would output the attribute "just
in case", which rather destroys the point of it.

Anyone who really wants confirmation that the document has been properly
closed can always finish it with

<?closed really="yes" truly="yes"?>

and check for that when reading. Dim memories of undergraduate lectures
remind me that there might be better ways of designing an error
checking/correcting code, and indeed a better layer of the stack to place it
in; but the above is at least as good as the current reliance on an end tag.

Michael Kay
http://www.saxonica.com/