W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > April 1997

Re: xmllink-970406 various

From: Terry Allen <tallen@sonic.net>
Date: Tue, 8 Apr 1997 17:25:39 -0700
Message-Id: <199704090025.RAA20216@bolt.sonic.net>
To: U35395@UICVM.UIC.EDU, w3c-sgml-wg@w3.org
Michael asked:
| Since this is so obvious I find it painful to say it, I can't believe
| I'm answering the question you really have in mind, though I'm
| answering the only question I can find in your query.  Answer me
| honestly, Terry:  is this a trick question?

No, not at all, and this response is in exactly the terms I wanted;
I think some parts of it should go in the spec.  It's what I thought
you all must have had in mind, but I wanted to be sure.

The circumstance I'm wondering about most is this:  I download an
XML instance, construct (a) XML TEI pointers into it using fragment IDs
and (b) XML TEI pointers into it using queries.  How do I know that
either will work in practice over the Net?  In the case of (a) it will suffice
that the server doesn't grok the pointer but anyway sends me the entire 
instance - that appears to work in a quick random test with HTML.  In the case 
of (b), quick random testing reveals that some servers return the
entire instance (not what was expected, some error recovery will
be needed there), or fail to return anything but an error message.

(b) is uncomfortable, because we don't want to have to keep track
of the capabilities of the server serving the XML, and they may
change anyway.  It looks as though the only way I can know the
queries work is to test them over the Net (potentially a real
drag), and even then they may break without warning if the XML
moves to another server or another server takes over serving it.
And breaking the query may break the URL entirely (is this itself
behavior noncompliant with HTTP?).

That's why I asked whether XML-compliant servers would be specified.

| >To rephrase, is this language applicable to XML only or to URLs
| >occurring in any context (HTML, VRML, ETF) pointing into XML?
| >Or does it apply to URLs generally?
| 
| It cannot apply to URLs generally because the defining RFCs say that it
| cannot and does not.

Again, that's what I thought you had in mind.  It's probably the expedient 
way to proceed, but I wonder if it wouldn't be better in the long run to
ask the URLists or HTTPers to make a way to state the query language
in use, perhaps to negotiate about it.  I imagine that issue has come
up before; Dan?

| Since I don't really understand the nature of your confusion, I have
| no idea whether I am clarifying matters for you or not.  If you are
| asking Socratic questions intended to lead me to see the fundamental
| error of my views, you aren't succeeding yet.

Socratic in not prompting for a specific answer, but not intended to
lead to you see the error of your views; I just wanted to know what
they were more fully.  

Regards,
  Terry Allen    Electronic Publishing Consultant    tallen[at]sonic.net
                   http://www.sonic.net/~tallen/
    Davenport and DocBook:  http://www.ora.com/davenport/index.html
          T.A. at Passage Systems:  terry.allen[at]passage.com 
Received on Tuesday, 8 April 1997 20:24:56 EDT

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