Appendix C. DocBook Versions
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This is an alpha version of this book.

## Appendix C. DocBook Versions

$Revision: 1.1 $

$Date: 2001/08/02 10:22:22 $

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:

- In major releases (4.0, 5.0, 6.0, and so on)

- Only if the change was described in comments in the DTD in the previous major release

Changes made at point-releases are always backward-compatible to the previous major release. This policy assures that DocBook users always have time to prepare for any coming changes.

This appendix describes the changes planned for DocBook.

## C.1. DocBook V3.1

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`

  A set of questions and answers.

`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.

## C.2. DocBook V4.1 and DocBook XML V4.1.2

DocBook V4.1 and DocBook XML V4.1.2 became an OASIS Standard in February 2001.

FIXME: Update this section!

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.

## C.3. DocBook 5.0

DocBook v5.0 will also introduce backward-incompatible changes.

These changes will be announced in version 4.0, although several were announced with version 3.1 as well.

Backward-incompatible changes to DocBook that are planned for version 4.0:

- DocBook 5.0 will be XML compliant. This will introduce a lot of changes.

- The `Coords` attribute will be removed from `AreaSet`.

- `ArtHeader` will be dropped from `BiblioEntry`.

- The `Contents` attribute will be removed from `BookInfo` and `SetInfo`.

- The `%indexdivcomponent.mix;` entity will be restricted. Numbered figures and other elements inappropriate for an `Index` or `SetIndex` will be removed.

- `RevHistory` will be removed from `GlossTerm`.

- The `Constant` `Class` will be removed from `SystemItem`.

- `Graphic` and `InlineGraphic` will be removed.

## C.4. DocBk XML

FIXME: update this section

The DocBk XML DTD is an XML version of DocBook produced by Norman Walsh. It is a faithful translation of DocBook, as described in Section B.2.

Although it has not been officially adopted by the DocBook Technical Committee, the TC does have concrete plans to produce an official XML version of DocBook in version 5.0. This is likely to be based on the DocBk XML DTD, or very closely resemble it.

The DocBk XML DTD is supplied on the CD-ROM. It is also available from http://nwalsh.com/docbook/xml/.

## C.5. EBNF Module

FIXME: write this section

## C.6. HTML Forms Module

FIXME: write this section

## C.7. MathML Module

FIXME: write this section

## C.8. SVG Module

FIXME: write this section

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Appendix B. DocBook and XML | Up | Appendix D. Resources

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