programlistingco
programlistingco — A program listing with associated areas used in callouts
Description
Callouts, such as numbered bullets, are an annotation mechanism. In an online system, these bullets are frequently “hot,” and clicking on them sends you to the corresponding annotation.
A ProgramListingCO
is a wrapper around an AreaSpec
and a ProgramListing
. An AreaSpec
identifies the locations (coordinates) in the ProgramListing
where the callouts occur. The ProgramListingCO
may also contain the list of annotations in a CalloutList
, although the CalloutList
may also occur outside of the wrapper, elsewhere in the document.
It is also possible to embed CO
elements directly in the verbatim text, in order to avoid having to calculate the correct coordinates. If you decided to go this route, use a ProgramListing
and a CalloutList
without the ProgramListingCO
wrapper. A ProgramListingCO
must specify at least one coordinate.
For a complete description of callouts, see Callout
.
Processing expectations
Formatted as a displayed block. This element is displayed “verbatim”; whitespace and linebreaks within this element are significant.
The mandatory processing expectations of a ProgramListingCO
are minimal: a system is expected to render the program listing and the callout list, if present.
If explicit CO
elements are embedded in a ProgramListing
, they must generate appropriate callout marks.
In online environments, the processing system may be able to instantiate the linking relationships between the callout marks in the program listing and the annotations. Some systems may even be able to go a step further and generate the callout marks automatically from the coordinate information, but this level of sophistication is not mandatory.
Parents
These elements contain programlistingco: answer
, appendix
, article
, bibliodiv
, bibliography
, blockquote
, callout
, caption
, caution
, chapter
, colophon
, constraintdef
, dedication
, entry
, example
, figure
, footnote
, glossary
, glossdef
, glossdiv
, important
, index
, indexdiv
, informalexample
, informalfigure
, itemizedlist
, legalnotice
, listitem
, msgexplan
, msgtext
, note
, orderedlist
, para
, partintro
, preface
, procedure
, qandadiv
, qandaset
, question
, refsect1
, refsect2
, refsect3
, refsection
, refsynopsisdiv
, revdescription
, sect1
, sect2
, sect3
, sect4
, sect5
, section
, setindex
, sidebar
, simplesect
, step
, taskprerequisites
, taskrelated
, tasksummary
, td
, textobject
, th
, tip
, variablelist
, warning
.
Children
The following elements occur in programlistingco: areaspec
, calloutlist
, programlisting
.
See Also
areaspec
, calloutlist
, co
, coref
, graphicco
, imageobjectco
, mediaobjectco
, screenco
.
Examples
<!DOCTYPE programlistingco PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<programlistingco>
<areaspec>
<areaset id="ex.plco.const" coords="">
<area id="ex.plco.c1" coords='4'/>
<area id="ex.plco.c2" coords='8'/>
</areaset>
<area id="ex.plco.ret" coords='12'/>
<area id="ex.plco.dest" coords='12'/>
</areaspec>
<programlisting>
sub do_nothing_useful {
my($a, $b, $c);
$a = new A;
$a->does_nothing_either();
$b = new B;
$c = "frog";
return ($a, $c);
}
</programlisting>
<calloutlist>
<callout arearefs="ex.plco.const">
<para>
These are calls to the constructor <function>new</function> in the object
classes.
</para>
</callout>
<callout arearefs="ex.plco.ret">
<para>
This function returns a two-element list.
</para>
</callout>
<callout arearefs="ex.plco.dest">
<para>
The <emphasis>destructor</emphasis> (<function>DESTROY</function>) for
the object <literal>$b</literal> will be called automatically for this
object since there can be no other references to it outside this function.
</para>
</callout>
</calloutlist>
</programlistingco>
sub do_nothing_useful {
my($a, $b, $c);
$a = new A;
$a->does_nothing_either();
$b = new B;
$c = "frog";
return ($a, $c);
}
These are calls to the constructor | |
This function returns a two-element list. | |
The destructor ( |