Re: [xsl] intra document link

Subject: Re: [xsl] intra document link
From: "G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>
Date: Wed, 18 Feb 2004 20:29:19 -0500
At 2004-02-18 22:50 +0100, Nikolas Nehmer wrote:
Hi, sorry it's me again.

No need to apologize!

I'm looking for a possibility of intra document links with xhtml. For
better imagination a little example:
For each chapter I would like to create a link, for
example a href to that chapter. When you klick that link the
visualisation for that Chapter should be displayed (e.g a table again).
Creating the visualisation is not my problem, but I don't know if there
is way to build those intra document links! Are there any possibilities,
any suggestions?

Absolutely ... the designers of XSLT provided for just this.

I frist thought about declaring an ID attribute for any
chapter but I don't know if I can point to that ID by html hrefs.

Yes, you could do that, but it is not necessary in XSLT.

Every node in every tree created for an XSLT process (all source trees and the stylesheet tree) is assigned a generated unique identifier. This identifier is an opaque value that is used in its entirety and is defined by the processor in any fashion it wishes, provided that the identifier lexically matches an XML NCName.

NCNames can, therefore, be used in HTML anchors as names and hrefs.

You ask the processor for a node's generated identifier using the function generate-id(nodeAddress) and every time you ask for that node's identifier in a given run of a stylesheet, you get the same value back. It may or may not be the same value the next time you run the stylesheet, so you cannot rely on any persistence so you cannot expect an identifier generated for a node in one run will be the same in the next run.

You take advantage of these generated identifiers to synthesize ID/IDREF relationships, not only where there are no ID values available, but I have learned through experience it is safest to use generated identifiers even for nodes that have ID values (this protects from ambiguities when dealing with multiple source trees with ID values in each).

When you process your chapter table of contents, you utilize the chapter's generated identifier in the href= attribute. To ensure there is something to point to when you process your chapter, you utilize the chapter's generated identifier in the name= attribute. The resulting file has resolved HTML hyperlinks from your TOC to your body.

   <xsl:for-each select="b:Book/b:chapters/iese.Chapter:Chapter">
       <a href="{generate-id(.)}">
         <xsl:value-of select="iese.Chapter:heading"/>
   <!--Body processing-->
   <xsl:for-each select="b:Book/b:chapters/iese.Chapter:Chapter">
       <a name="{generate-id(.)}">
         <xsl:value-of select="iese.Chapter:heading"/>
     <!--rest of chapter processing-->

I hope this helps.

............................. Ken

p.s. I am teaching XSLT/XPath/XSL-FO in May in Bremen ... if you could please help spread the word to any local XML user groups, it would be greatly appreciated; thanks!

Public courses: upcoming world tour of hands-on XSL training events
Each week:    Monday-Wednesday: XSLT/XPath; Thursday-Friday: XSL-FO
Washington, DC: 2004-03-15            San Francisco, CA: 2004-03-22
Hong Kong: 2004-05-17    Germany: 2004-05-24    England: 2004-06-07
World-wide on-site corporate, government & user group XML training!

G. Ken Holman                  mailto:gkholman@xxxxxxxxxxxxxxxxxxxx
Crane Softwrights Ltd. 
Box 266, Kars, Ontario CANADA K0A-2E0     +1(613)489-0999 (F:-0995)
Male Breast Cancer Awareness

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