The value -dita-use-conref-target is available on enumerated
attributes and may also be specified on other attributes. When an
element uses conref to pull in content, for any of its attributes
assigned a value of "-dita-use-conref-target", the resulting value
for those attributes should also be pulled in from the referenced
element.
Ordinarily, when an element uses conref, any other attributes
specified locally will be preserved when the reference is resolved. This
causes problems when attributes are required, because required attributes
must be specified regardless of whether the conref attribute is present. The purpose of the -dita-use-conref-target value is to allow
the author to specify a value for a required attribute while still
allowing the conref resolution process to use the matching attribute
from the referenced element. The value has the same result when the
attribute is not required.
Example
This example shows
a map where the topichead element uses conref. It specifies the navtitle
attribute as well as the toc attribute. In the resolved element, navtitle
is not preserved because it uses -dita-use-conref-target; the toc
attribute overrides the toc attribute on the referenced element using
normal conref resolution rules.
Figure 3-63. Pre-resolution
<map><title>Conref demonstration</title>
<topichead id="heading"
navtitle="This is a heading"
toc="yes"
print="yes">
<topicref href="topic.dita" navtitle="content"/>
</topichead>
<topichead conref="#heading"
navtitle="-dita-use-conref-target"
toc="no">
</topichead>
</map>
Figure 3-64. Effective result post-resolution
<map><title>Conref demonstration</title>
<topichead id="heading"
navtitle="This is a heading"
toc="yes"
print="yes">
<topicref href="topic.dita" navtitle="content"/>
</topichead>
<topichead navtitle="This is a heading"
toc="no"
print="yes">
<topicref href="topic.dita" navtitle="content"/>
</topichead>
</map>
