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xref — A cross reference to another part of the document
xref ::= EMPTY
Name |
Type |
Default |
xrefstyle | CDATA | None |
endterm | IDREF | None |
linkend | IDREF | Required |
The XRef
element forms a cross-reference from the location
of the XRef
to the element to which it points. Unlike
Link
and the other cross-referencing elements, XRef
is empty. The processing system has to generate appropriate cross-reference
text for the reader.
Under ordinary circumstances, the xref
points to the some element with its
linkend
attribute and the processing system
generates appropriate cross reference text. There are three
ways for the author to influence the generated text:
If the endterm
attribute is specified
on xref
, the
content of the element pointed to by endterm
will be used as the text of the cross-reference.
Otherwise, if the object pointed to has a
specified XRefLabel
, the content of
that attribute will be used as the cross-reference text.
Finally, the author may specify a keyword (or other information) in the
xrefstyle
attribute. Unlike
endterm
and
xreflabel
which have rigid semantics,
the content of the xrefstyle
attribute is simply
additional information for the processing system. What effect it has, if any,
is dependent on the processing system.
These elements contain xref:
application
, attribution
, bibliomisc
, bridgehead
, citation
, citetitle
, emphasis
, entry
, firstterm
, foreignphrase
, glosssee
, glossseealso
, glossterm
, lineannotation
, link
, literallayout
, lotentry
, member
, msgaud
, olink
, para
, phrase
, primary
, primaryie
, productname
, programlisting
, quote
, refentrytitle
, refpurpose
, remark
, screen
, screeninfo
, secondary
, secondaryie
, see
, seealso
, seealsoie
, seeie
, seg
, segtitle
, simpara
, subtitle
, synopsis
, td
, term
, termdef
, tertiary
, tertiaryie
, th
, title
, titleabbrev
, tocback
, tocentry
, tocfront
, ulink
.
Endterm
points to the element whose content
is to be used as the text of the link.
Linkend
points to the target of the cross reference.
Consider the following example:
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd"> <book><title>An Example Book</title> <chapter id="ch01"><title>XRef Samples</title> <para> This paragraph demonstrates several features of <sgmltag>XRef</sgmltag>. </para> <itemizedlist> <listitem><para>A straight link generates the cross-reference text: <xref linkend="ch02"/>. </para></listitem> <listitem><para>A link to an element with an <sgmltag class="attribute">XRefLabel</sgmltag>: <xref linkend="ch03"/>. </para></listitem> <listitem><para>A link with an <sgmltag class="attribute">EndTerm</sgmltag>: <xref linkend="ch04" endterm="ch04short"/>. </para></listitem> </itemizedlist> </chapter> <chapter id="ch02"> <title>The Second Chapter</title> <para>Some content here</para> </chapter> <chapter id="ch03" xreflabel="Chapter the Third"> <title>The Third Chapter</title> <para>Some content here</para> </chapter> <chapter id="ch04"> <title>The Fourth Chapter</title> <titleabbrev id="ch04short">Chapter 4</titleabbrev> <para>Some content here</para> </chapter> </book>
One reasonable rendering for the content of the first chapter of this book is the following:
This paragraph demonstrates several features of
XRef
.
A straight link generates the cross-reference text: Chapter 2, “The Second Chapter”
A link to an element with an
XRefLabel
:
Chapter the Third.
A link with an
EndTerm
:
Chapter 4.
Of course, in an online system, these references would also be links to the appropriate chapters.
For additional examples, see also
part
.