Cross Reference Text and Styles

You can customize the style of the automatic cross reference text using the xrefstyle document attribute. This customization brings the cross reference text formatting from the DocBook toolchain to AsciiDoc processing, specifically during conversion.

Since this is a newer feature of the AsciiDoc language, it may not be supported by all converters. Where you can find support for it is in Asciidoctor’s HTML, PDF, and EPUB 3 converters. It’s not supported by the DocBook converter since it’s a feature the DocBook toolchain already provides.

Default styling

By default, the cross reference text matches the title of the referenced element. For example, if you’re linking to a section titled “Installation”, the text of the cross reference link appears as:

Installation

If the reftext attribute is specified on the referenced element, that value is preferred over its title. For example, let’s assume the section from the previous example was written as:

[reftext="Installation Procedure"]
=== Installation

In this case, the text of the cross reference link appears as:

Installation Procedure

Attribute references are substituted in the reftext during parsing and reftext substitutions (specialchars, quotes, and replacements) are applied to the value when it’s used during conversion.

If the reftext is not specified, the text of the cross reference is automatically generated. By default, this text is the title of the reference.

Cross reference styles

There are three built-in styles you can choose from to customize the generated text of a cross reference, as controlled by the xrefstyle document attribute.

:xrefstyle: full

Uses the signifier for the reference (e.g., Section) followed by the reference number and emphasized (chapter or appendix) or quoted title (e.g., Section 2.3, “Installation” or Figure 1, “Big Cats”).

:xrefstyle: short

Uses the signifier for the reference (e.g., Section) followed by the reference number (e.g., Section 2.3 or Figure 1).

:xrefstyle: basic

Uses the title only (Installation or Big Cats), applying emphasis if the reference is a chapter or appendix.

This formatting only applies to references that have both a title and number (or explicit caption), but no explicit reftext. If the reference is a chapter or an appendix, the title is displayed in italics instead of quotes (even when the xrefstyle is basic).

Let’s assume you want to reference a section titled “Installation” that has the number 2.3. The full style is displayed as:

Section 2.3, “Installation”

The short style is displayed as:

Section 2.3

The basic style is displayed as:

Installation

The full and short styles only apply for references that have a caption. Specifically, the corresponding -caption attribute must be set for the target’s block type (e.g., listing-caption for listing blocks, example-caption for example blocks, table-caption for tables, etc.). Otherwise, the *basic style is used.

Reference signifiers

You can use document attributes to customize the signifier that is placed in front of the reference’s number. This reference signifier indicates the reference’s type (e.g., Chapter or Section).

  • chapter-refsig — defines the signifier to use for a cross reference to a chapter (default: Chapter)

  • section-refsig — defines the signifier to use for a cross reference to a section (default: Section)

  • appendix-refsig — defines the signifier to use for a cross reference to an appendix (default: Appendix)

(The signifier attribute for a part cross reference will be introduced once numeration is supported for parts).

For example, to customize the word “Section”, define the section-refsig attribute in the document header:

:section-refsig: Sect.

The full xrefstyle would then be displayed as:

Sect. 2.3, “Installation”

The short xrefstyle would be displayed as:

Sect. 2.3

If you unset the attribute, the signifier is dropped from the cross reference text. For example:

:!section-refsig:

In this case, the full xrefstyle will display only the number and title:

2.3, “Installation”

The short xrefstyle will fall back to the number only:

2.3

The basic xrefstyle is unaffected by the value of the signifier.

Only the aforementioned styles are provided out of the box. Support for a custom formatting string is planned. Refer to #2212 for details. Until then, you can implement custom formatting in a custom converter or overridding the xreftext method on the node.