Data

Data is a generic component that represents metadata within a topic or map. Complex metadata is represented by nested data structures.

Syntax

The syntax for representing this component varies depending on the authoring format:

Authoring format Syntax and example
XDITA

<data>

<data name="author" value="Victoria Fernando"/>
HDITA

<meta>

<head>
  <title>An innovative, attractive, and out of the ordinary concept</title>
  <meta name="author" content="Victoria Fernando">
</head>
MDITA

There is no specific syntax for data in MDITA core profile. In the MDITA extended profile, data is represented by variables declared in a YAML front-matter header. The front matter must be the first block in the file, and it must be set between triple-dashed lines. 

---
author: Victoria Fernando
---

Usage information

A metadata property specified using a <data>component usually applies to the structure that contains the <data> component.

CAUTION: By default, processors do not render the content of the <data> component. Use the <data> component only for properties; do not use it to embed text as part of the content flow.

Rendering expectations

By default, processors SHOULD treat a data component as unknown metadata. The contents of the data component SHOULD NOT be rendered.

Processors that recognize a particular data component MAY make use of it to trigger specialized rendering.

Attributes

The available attributes vary based on the authoring format:

XDITA
The following attributes are available on this element: data-element attributes, link relationship attributes, localization attributes, universal attributes, @keyref, and @props.
HDITA
The following attributes are available on this element: link relationship attributes, localization attributes, universal attributes, @keyref, and @props.
MDITA
For the MDITA core profile, the equivalent of the XDITA @keyref attribute is supported. For the MDITA extended profile, attributes can be specified by using the HDITA representation.

Examples

This section contains examples of how the data component can be used in the three authoring components:

Figure 1. XDITA example

The following code sample shows how the <data> element can be used to trigger specialized processing in an XDITA topic. The company has implemented specialized processing that renders a list of prerequisite items at the location of the <data> element.

<topic id="installing-acme-test-suite">
  <title>Installing the Acme Test Suite</title>
  <shortdesc>Install the Acme Test Suite in order to test whether your
             applications will work with the Acme core code.</shortdesc>
  <body>
    <section>
      <title>Before you begin</title>
      <p>You will need the following items:</p>
      <data name="trigger" value="generatePrereqList"/>
    </section>
    <!-- ... -->
  </body>
</topic>

For an example of how the <data> element can be used in the topic prolog to specify metadata, see <data>.

Figure 2. HDITA example

The following code sample shows how data components can specify metadata that applies to the topic as a whole. The <head> element holds three <meta> elements, which store metadata about the author, product, and user goal that is associated with the topic.

<head>
  <title>Installing the Acme Test Suite</title>
  <meta name="author" content="Carolyn Miller"/>
  <meta name="product" content="Acme Test Suite"/>
  <meta name="goal" content="installing"/>
</head>
Figure 3. MDITA example

The following code sample shows how topic-level metadata can be represented an MDITA extended profile topic. The data components are represented by variables declared in a YAML front-matter header, which provide information about the author, product, and user goal that is associated with the topic.

---
author: Carolyn Harris
product: Acme Test Suite
goal: installing
---