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Re: xmllink-970406 various

From: Peter Murray-Rust <Peter@ursus.demon.co.uk>
Date: Mon, 21 Apr 1997 13:51:08 GMT
Message-Id: <5860@ursus.demon.co.uk>
To: w3c-sgml-wg@w3.org
I have been struggling with the precise implementation of XML-LINK 5.2 and 5.3
and while I think I have the intention of the draft, I find ambiguity.

5.2. Production [1] states that after a connector there may either be a 
Name or an Xpointer.  Xpointer is defined [4] but there is no definition of
Name.  (I assume this to be the same definition as in XML-LANG, but the 
BNF namespaces are apparently separate (Element is defined in 
both and differs - unless 'element' and 'Element' are held to be different).

The construction HREF="Foo#HERE" is therefore ambiguous since it is unclear
whether HERE is an attribute of type ID or the reserved word HERE (similarly for
ROOT).


5.3 second bullet.  'beginning and end of a span' ... 'FROM and TO'.  This 
is unclear to anyone not from the TEI community (which includes me :-).  In 5.3
below it talks about 'all the text from the location'.  I am unclear what to 
do with the following (please imagine there are no newlines and inter-tag
whitespace so magic #PCDATA isn't involved):
<COMPANY ID="FOO">
  <DIVISION ID="MIS">
    <EMPLOYEE ID="DON">
    <EMPLOYEE ID="SUE">
  </DIVISION>
</COMPANY>
What is the result of the valid query:
	#ID(FOO)..ID(DON)

It might be: (a) a null string since there is no _text_ enclosed
	     (b) invalid since it could be seen as not well-formed
	     (c) equivalent to:
<COMPANY ID="FOO">
  <DIVISION ID="MIS">
    <EMPLOYEE ID="DON">
  </DIVISION>
</COMPANY>

[A general comment is that this section is written as if the documents are 
primarily text with a few embedded tags.  It's quite meaningful to create
XML documents with no #PCDATA at all.]

5.3.1  ROOT is twice referred to as 'the default' and this fooled me into
thinking it could be omitted.  I have read this carefully and it
is not a default since it has the same status as HERE and ID.  The sentence
'the presence of the ROOT keyword has no effect...' seems to be wrong.  If
the ROOT keyword is omitted I hope an error would result :-)

	P.



-- 
Peter Murray-Rust, domestic net connection
Virtual School of Molecular Sciences
http://www.vsms.nottingham.ac.uk/
Received on Monday, 21 April 1997 09:22:04 EDT

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