RE: attribute order (RE: Syntax Sugar and XML information models)

["Simon St.Laurent" <simonstl@simonstl.com>]

At 11:33 AM 3/29/01 -0500, Mike.Champion@SoftwareAG-USA.com wrote:
>Thanks for looking this up!  But, uhhh,  "Note that the order of attribute 
>specifications in a start-tag or empty-element tag is not significant" is 
>pretty explicit.  I think the InfoSet has gone a bit far in implying the 
>insignificance of various things that databases and editors need to 
>preserve, but I wouldn't want to have anything to do with an effort to 
>imply significance to things that XML 1.0 defines as NOT significant.

Sure - I was just pointing out that the rule was something of a latecomer 
to XML 1.0, appearing only in the Second Edition.  It's certainly explicit, 
but I think there's plenty of good reason to question why that was seen as 
important enough to rate an explicit change to the spec.

Remember that we don't all have access to the archives, and I can imagine a 
number of reasons for arguing either way.  (It's pretty easy to argue about 
how useful the various distinctions between elements and attributes really 
are in general - this is just one case.)

>I just remembered one other thing that the InfoSet doesn't model that has 
>generated some discussion about round-trippability --- the two legal XML 
>syntaxes for empty elements.  Does anyone care about round-tripping the 
>specific syntax used in some instance, e.g. <empty></empty> vs <empty/> 
>?  There was some discussion on SML-DEV once about using it to encode the 
>distinction between an element with the value [empty string] vs an element 
>with the value "null"  ... but the fact that the distinction wouldn't 
>necessarily survive a round-trip with an InfoSet-compliant tool put that 
>idea to rest.

If XML 1.0 had genuinely described only a syntax, I think the distinction 
between the two would be preserved.  Since it defined a syntax with some 
processing notions behind it, and the Infoset people have codified those 
notions, I think those possibilities disappeared.


Simon St.Laurent - Associate Editor, O'Reilly and Associates
XML Elements of Style / XML: A Primer, 2nd Ed.
XHTML: Migrating Toward XML
http://www.simonstl.com - XML essays and books