The OASIS DocBook Technical Committee (TC) is committed to the continued evolution of DocBook. As new needs are expressed by the DocBook-user community, the committee will adapt DocBook so it continues to meet the needs of its users.
The TC observes a very cautious policy regarding changes to the DTD. Backward-incompatible changes can only be introduced:
This appendix describes the changes planned for DocBook.
DocBook V3.1, released in February 1999, introduced a number of new elements:
MediaObject
MediaObject
is a wrapper around
VideoObject
, AudioObject
,
ImageObject
, and TextObject
. The
purpose of MediaObject
is twofold: first, it introduces
new element types to include video and audio content; second, it
provides the option of alternative representations, including text, for
objects in a document. MediaObject
s also allow
Caption
s that may be longer than a simple title.
Parallel to MediaObject
are InlineMediaObject
,
an inline version, and MediaObjectCO
, a media object
with Callout
s.
For now, media objects and graphics exist together
in version 5.0. Graphic
and InlineGraphic
will
be removed from DocBook.
InformalFigure
A figure wrapper without a title. This element was added largely for symmetry.
Colophon
An end-of-the-book Colophon
.
Section
Section
is a recursive section. It exists
parallel to, and must be used as an alternative to,
Sect1
.
QandASet
Constant
The Constant
inline is for identifying
constants. It has a Class
attribute for
identifying “limits” as a specific kind of constant.
VarName
Many authors have requested a tag for identifying
variable names. Most often Literal
(with or without a role)
has been chosen as a compromise, but you can't question the utility of identifying variable
names, so VarName
was added.
A tag for identifying variable values does not seem as necessary.
For immutable values, a specific tag other than Literal
seems unnecessary, and Replaceable
exists for values that
are supposed to be filled in by the user.
DocBook V4.1 and DocBook XML V4.1.2 became an OASIS Standard in February 2001.
DocBook V4 introduced a number of backward-incompatible changes.
The policy of the DocBook TC is that backward-incompatible changes can only be introduced in a full version release. They must also be described in comments in the DTD at least one full version earlier. In other words, all the planned version 4.0 incompatibilities were announced with version 3.0.
Backward-incompatible changes to DocBook that are planned for version 4.0:
The DocInfo
element will be split out into ChapterInfo
, AppendixInfo
,
and so on. ArtHeader
will be renamed to ArticleInfo
. SeriesInfo
may be
discarded because it has become a special case of BiblioSet
.
BookBiblio
will be discarded in favor of a new, more inclusive,
structure for BookInfo
(and for ArticleInfo
, whose earlier ArtHeader
form contained BookBiblio
).
The %article.class;
entity may be removed from the Book
content model,
and made part of a new top-level document hierarchy.
The %nav.class;
entity, which appears in several divisions, will allow
ToCchap
instead of ToC
.
MsgText
will be moved from %tech.char.class;
to a more appropriate
parameter entity.
The following elements will have their content constrained to the
%smallcptr.char.mix;
mixture: Action
, Command
, Database
, Filename
,
Hardware
, Interface
, KeyCap
, Literal
, Option
, Parameter
, Property
, and
SystemItem
.
AuthorBlurb
and Affiliation
will be removed from %person.ident.mix;
and a new wrapper element will be created to allow association of those two
elements with Author
name information.
Epigraph
will not be appearing in BlockQuote
.
Comment
will be renamed to Remark
and will be excluded from itself.
GlossTerm
will be excluded from itself, and may be split into an
element that appears in a Glossary
and an element that can appear in
the main text.
The Subject
attribute on GlossDef
will be renamed Keyword
.
Two SegTitle
elements will be required in SegmentedList
.
Graphic
and InlineGraphic
will be declared EMPTY. This change will
require that end tags be removed and that any embedded graphic content
be stored outside the SGML source and pointed to from an Entityref
or
Fileref
attribute.
The OptMult
and ReqMult
values for the Choice
attribute on Group
will be removed. Use the Rep
attribute instead to indicate that the
choice is repeatable.
The content model group inside FuncSynopsis
starting with FuncDef
will not be available; you will have to use FuncPrototype
. Also, you
will be able to have a mixture of FuncPrototypes
and FuncSynopsisInfos
(this is not backward-incompatible all by itself).
The EnvironVar
and Prompt
values for the Class
attribute on SystemItem
will be eliminated; use the EnVar
and Prompt
elements instead.
DocBook V4.2 fixed a couple of small bugs and introduced a number of new features. Changes in DocBook V4.2 are explained in the DocBook Document Type Version 4.2.