xml-dev - Re: Why the Infoset?

[Rick JELLIFFE <ricko@geotempo.com>]

Kay Michael wrote:
  
> For example the two documents below have the same core infoset but different
> canonical forms:
> 
> 1: <x:a xmlns:x="one.uri"/>
> 2: <y:a xmlns:y="one.uri"/>
> 
> While these two have the same canonical form but different core infosets:
> 
> 1: <x:a xmlns:x="one.uri"><x:b/></x:a>
> 2: <x:a xmlns:x="one.uri"><x:b xmlns:x="one.uri"/></x:a>

But in both those examples, if you canonicalize them then they have the
same core infoset. (Can someone confirm that?)

> So in my book, the essential question "when do two XML documents convey the
> same information" remains unanswered.

I don't think the infoset does attempt to answer that question. That is
what c14n does. In fact, I hope the infoset does not attempt to answer
that question: the answer to a question like "should we normalize
characters LOWERCASE LATIN LETTER U and COMBINING DIARESIS into
LOWERCASE LATIN LETTER U WITH DIARESIS?" can legitimately be different
for a c14n spec interested in comparisons and an infoset spec interested
in identifying what W3C working groups should conservatively take as the
information items available from a parsed XML document.

Rick Jelliffe