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Re: Announcing HLink: rationale

From: Norman Walsh <Norman.Walsh@Sun.COM>
Date: Fri, 13 Sep 2002 13:36:53 -0400
To: www-tag@w3.org
Message-ID: <87n0qlokp6.fsf@nwalsh.com>

/ "Steven Pemberton" <steven.pemberton@cwi.nl> was heard to say:
| intended to be used by other languages. Some languages can be both host and
| integration (SVG for instance, and XHTML is also used this way by some).

I'm having trouble understanding the value of the host/integration
language distinction. The nature of namespaces is such that I can host
your language in my vocabulary and vice-versa.

| 1) Suppose we have an integration language 'XML Handlers', that has an
| element
|
|     <script>
|         a=b
|     </script>
|
| and as an option the <script> element may have an attribute pointing to an
| external resource:
|
|     <script src="/scripts/pop" />
|
| and someone complains that this should use XLink, so it gets changed to:
|
|     <script xmlns:xlink="http://www.w3.org/1999/xlink"
|         xlink:href="/scripts/pop" xlink:type="simple" xlink:show="embed"
|         xlink:actuate="onLoad" />

I think that's an unlikely scenario. XLink, especially with
xlink:show='embed' is about presentation to users, not references to
resources that aren't human readable.

The semantics of your example above are that the document at
/scripts/pop should be styled and the styled result should be embedded
in place of the <script/> element.

| 2) Suppose we have another integration language "XML Security" that requires
| adding references to security preference files via a URL
| xsecurity:preferences="..."
|
|     <myElement xsecurity:preferences="/security/pref1.xsp">
|         ...
|     </myElement>
|
| Someone says they should make this XLink compatible, so they instead
| just define a new xlink:role "http://example.org/security":
|
|     <myElement xlink:href="/security/pref1.xsp" xlink:type="simple"
|         xlink:show="embed"
|         xlink:actuate="onLoad" xlink:role="http://example.org/security" />

This example suffers from the same "embed" flaw.

| 3) And then along comes the XML Privacy group that introduces the XML
| Privacy specification that says that in order to reference a privacy
| preference file from XML, you have to put a URL ... no let's not do that
| today.
|
| All we wanted to say was
|
|     <script src="/scripts/pop"
|       xsecurity:preferences="/security/prefs1.xsp"/>
|
| HLink, just released, allows you to define this.
| http://www.w3.org/TR/hlink/

HLink is interesting. But your examples don't offer much motivation to me.

Can you construct a similar example using xlink:show='replace'? And
preferably using examples of links from one hypertext document to
another intended for traversal by humans (or at least for the purpose
of human reading)?

                                        Be seeing you,
                                          norm

-- 
Norman.Walsh@Sun.COM    | The fact of having been born is bad augury
XML Standards Architect | for immortality.--Santayana
Sun Microsystems, Inc.  | 
Received on Friday, 13 September 2002 13:37:37 GMT

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