    | DocBook: The Definitive Guide 0.0.12 for DocBook V5.0b1 (Alpha) |
| | DocBook: The Definitive Guide 0.0.12 for DocBook V5.0b1 (Alpha) |
synopfragmentref — A reference to a fragment of a command synopsis
A complex CmdSynopsis can be made more manageable
with SynopFragments. Rather than attempting to
present the entire synopsis in one large
piece, parts of the synopsis can be extracted out and presented
elsewhere.
At the point where each piece was extracted, insert a
SynopFragmentRef that points to the fragment. The
content of the SynopFragmentRef will be presented inline.
The extracted pieces are placed in SynopFragments
at the end of the CmdSynopsis.
The content model of SynopFragmentRef is unique in
the SGML version of DocBook because it contains RCDATA
declared content. What this means is that all markup inside a
SynopFragmentRef is ignored, except for entity references.
How, you might ask, is this different from a content model that
includes only #PCDATA? The difference is only
apparent when you consider inclusions. Recall that an inclusion
provides a list of elements that can occur anywhere
inside an element. So, for example, the fact that
Chapter lists IndexTerm as an inclusion
means that IndexTerm can legally occur inside of a
SynopFragmentRef that's nested inside a chapter,
even if the content model of SynopFragmentRef does
not explicitly allow IndexTerms. Making the content
RCDATA ensures that the markup will not be recognized,
even if it's allowed by inclusion. A neat trick.
XML does not support RCDATA.
Formatted as a displayed block.
The presentation system is responsible for generating text that makes the reader aware of the link. This can be done with numbered bullets, or any other appropriate mechanism.
Online systems have additional flexibility. They may generate hot links between the references and the fragments, for example, or place the fragments in pop-up windows.
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| synopfragment | | synopsis |