FW: Comments on Section 2.6 of XML-Namespaces

[Andrew n marshall]

Andrew n marshall
  student - artist - programmer
    http://www.media-electronica.com/anm-bin/anm
      "Everyone a mentor,  Everyone a pupil"

-----Original Message-----
From:	Andrew n marshall [SMTP:amarshal at usc.edu]
Sent:	Sunday, March 29, 1998 8:32 AM
To:	'tbray at textuality.com'; 'dmh at corp.hp.com'; 'andrewl at microsoft.com'
Cc:	'XML-L at LISTSERV.HEA.IE'
Subject:	Comments on Section 2.6 of XML-Namespaces


<!-- Because the XML-Namespace draft does not refer to mailing list open to 
public discussion, I have posted this on the XML-L listserv -->

In section 2.6 of your initial draft of XML Namespaces you comment on the 
possible ambiguity of specifying a namespace for an element's attribute, 
where more than one element may hold that attribute.  I find this notation 
to be problematic and not useful.

Beginning with your first example:
  <Warning html:class='Important'>Sudden death may ensue.</Warning>

While you point out that this there is no grammatical or conceptual errors 
here since all HTML elements define the class attribute, there is no 
guarantee from the DTD that they mean the same thing in use.  While it 
happens that they do mean the same thing in HTML, allowing this namespace 
syntax fails to resolve the ambiguity on mean in other possible XML 
applications.

Even in your attempt to rectify this situation with the syntax used in your 
last example:
  <Item T.Heat:Temp='5400'/>
You still provide no guarantee that there is a meaning for the attribute 
'Temp' without possible sibling attributes.  Take for example:
   <Item HTML.a:href='mypage.html'>
Does the use of href have any meaning without the 'target' attribute which 
may be implicitly be defined with the default value of '_self'?  Probably 
not.  Therefore does it make sense to pull an attribute out of its normal 
context?  Probably not.

For these reason, I suggest that namespaces specification limit itself to 
the namespaces of elements, which have well defined meanings and can be 
validated against their appropriate DTDs.

The attempts to solve the above problems should left up to the next version 
of XML which will hopefully define a way to describe attribute inheritance 
between element types and abstract element definitions.  Such a scheme will 
allow the reuse attributes without the above ambiguities in meaning.


Andrew n marshall
  student - artist - programmer
    http://www.media-electronica.com/anm-bin/anm
      "Everyone a mentor,  Everyone a pupil"


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