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Content re-use
Variables
Using internal entities for variables
Internal entities are an XML feature for creating typing shortcuts. They should be avoided in DITA authoring.

Introduction
Information types and topics
Topics are the building blocks of modular documents, and organising topics by semantic information types is one of the architectural features of DITA.
DITA map files
Syntax and mark-up
Language and punctuation
Graphics and figures
Cross-referencing
Cross-references are a means of binding individual topics into a coherent and navigable document.
Content re-use
- Content re-use definition
  Content re-use is a means of improving efficiency by eliminating repetition of phrases, blocks of text, topics, and even collections of topics.
- Re-use and the DITA Maturity Model
  Content re-use is one of the features that you should adopt early in your move from style-based authoring to structured authoring with DITA.
- The content reference (conref) attribute
  The conref feature allows DITA content to be used in any number of different places in a collection. The conref attribute in a referencing topic specifies the source topic and the element within that topic to re-use.
- Re-use practices
- Variables
  - Variables using conref and filtering
    Single-source publishing relies heavily on the concept of variables. While DITA does not have a specifically named variables feature, it does readily support variables functionality.
  - Variables using indirection
    The keyword element can be used as a container for variable words and phrases, when used in conjunction with the keydef element in the ditamap. Rather than enter the value of the keyword directly into the element, you can indirectly reference it through a key.
  - Using internal entities for variables
    Internal entities are an XML feature for creating typing shortcuts. They should be avoided in DITA authoring.
- Organising re-use topics and elements
- Embedded topics and ditamaps
  The ditamap is a powerful tool for re-using topics in different output publications. Topics can also be re-used using ditabase topics, but you should avoid this technique.
- Advanced conref principles
Metadata, conditional processing, and indexing
The DITA documentation process
DITA authoring concepts
Moving from style-based authoring to a structured authoring methodology such as DITA requires a radically different approach to writing.

Using internal entities for variables

Internal entities are an XML feature for creating typing shortcuts. They should be avoided in DITA authoring.

Internal entities function as typing shortcuts in XML documents. They allow a string or phrase to be defined in the head of the XML file, and then used in the body of the content using a shortcut notation. For example, the phrase Supara Lumberer may be defined as <!ENTITY lumberer "Supara Lumberer">, and that lumberer entity used within the document as &lumberer;. They can theoretically be used for creating variables.

Do not use internal entities. Their use inhibits interchange, and they are technically difficult for authors to work with. They are also changed during XSL transformations, resulting in inconsistent output results.