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Re: Number of Links and Nesting

From: Wolfgang May <may@informatik.uni-freiburg.de>
Date: Fri, 09 Aug 2002 14:32:20 +0200
Message-ID: <3D53B654.C00A9873@informatik.uni-freiburg.de>
To: www-xml-linking-comments@w3.org

Hi,

On Wed, Jul 10 2002, Ronald Daniel (rdaniel@interwoven.com) wrote

> > 2. Can nesting of links occur and if so is there a limit on the nesting
> > level?

> 2) Links don't nest. (If you have a real need for nested links,
>    we would be interested in hearing about it).

Here is an example where a solution with nested XLink elements
(simple links inside locators) is at least reasonable:

Consider 3 types A,B,C of resources.
Resources of type A are located at urlA; analogously for
B, C.

There is an application that combines triples of one A, one B and one
C, where the choice of the resource of type B is functionally
dependent on the choice of the A.

A possible XML instance using nested XLink elememts is given below:

<triples xlink:type="extended">
  <pair xlink:type="locator" xlink:href="urlA#id('a1')" id="pair-a1">
    <theB xlink:type="simple" xlink:href="urlB#id('b3')"/>
  </pair>
  <pair xlink:type="locator" xlink:href="urlA#id('a2')"id="pair-a2">
    <theB xlink:type="simple" xlink:href="urlB#id('b4')"/>
  </pair>
  <pair xlink:type="locator" xlink:href="urlA#id('a3')" id="pair-a3">
    <theB xlink:type="simple" xlink:href="urlB#id('b1')"/>
  </pair>
  :
  <theC xlink:type="locator" id="c1" xlink:href="urlC#id('c1')"/>
  <theC xlink:type="locator" id="c2" xlink:href="urlC#id('c2')"/>
  <theC xlink:type="locator" id="c3" xlink:href="urlC#id('c3')"/>
  :
  <triple xlink:type="arc" xlink:from="pair-a1" xlink:to="c2"/>
  <triple xlink:type="arc" xlink:from="pair-a1" xlink:to="c3"/>
  <triple xlink:type="arc" xlink:from="pair-a2" xlink:to="c1"/>
  <triple xlink:type="arc" xlink:from="pair-a3" xlink:to="c1"/>
  :
<triples/>

Obviously, there is the possibility to un-nest the XML instance by
having the <pair> elements as separate arcs in a separate extended
link.

Since it is allowed to have element contents in XLink elements, I
don't see any reason why this contents should not also contain nested
XLink contents.

Wolfgang
Received on Friday, 9 August 2002 08:32:27 GMT

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