Name
olink — A link that addresses its target indirectly
Synopsis
olink ::= (text | Bibliography inlines | Error inlines | Graphic inlines | GUI inlines | Indexing inlines | Keyboard inlines | Linking inlines | Markup inlines | Math inlines | Object-oriented programming inlines | Operating system inlines | Product inlines | Programming inlines | Publishing inlines | Technical inlines | Ubiquitous inlines)*
Description
Unlike link, the semantics of
olink are application specific. The
olink element provides a mechanism for establishing
links across documents, where ID/IDREF linking is not possible and
URI-based linking may be inappropriate.
In general terms, the strategy employed by
olink is to point to the target document by URI, and
point into that document in some application-specific way.
Other elements can also behave like olink by
using the common linking attributes xlink:href and xlink:role. When an element has an
xlink:role="http://docbook.org/xlink/role/olink"
attribute, then its xlink:href
attribute is interpreted using olink semantics. That
is, the part of xlink:href before
the fragment identifier (#) is interpreted as equivalent to an
olink targetdoc
attribute value instead of a URI, and the part after the fragment
identifier as an olink targetptr attribute value.
Processing expectations
Formatted inline.
An olink points to its target primarily with
the targetdoc attribute. The
targetdoc is a URI that
identifies a target document.
The semantics of the link are controlled by three other
attributes: targetptr, localinfo, and type.
The targetptr attribute
(possibly in conjunction with localinfo) points into the document in
some fashion. The type may
provide some additional, application-specific information about the
link. DocBook does not provide any semantics for the values of these
attributes.
Note
The targetptr and
localinfo attributes were
developed somewhat independently and arguably have somewhat
overlapping semantics. While almost all applications can certainly
get by with one or the other, the Technical Committee has decided
that removing localinfo simply
for semantic cleanliness isn’t worth the effort.
Linking elements must not be nested within other linking elements (including themselves). The processing of nested linking elements is undefined.
Attributes
- localinfo
Holds additional information that may be used by the application when resolving the link
- targetdoc
Specifies the URI of the document in which the link target appears
- targetptr
Specifies the location of the link target in the document
- type
Identifies application-specific customization of the link behavior
- xrefstyle
Specifies a keyword or keywords identifying additional style information