The <context> Element

Definition and Usage

The <context> element allows for structuring an NCL application. The element may contain elements with media content (<media> elements), called media objects, other nested <context> elements, elements grouping content alternatives (<switch> elements), and relationships (<link> elements) among all the objects represented by the aforementioned elements.

It should be stressed that the <body> element is considered a special kind of context, the one representing the whole application.

The <context> element may refer to another <context> or an imported <body> element. In this case, it inherits the specification of the referred element.


Element Attributes Content Parent
<context> id, refer (<port> | <property> | <media> | <context> | <link> | <switch> | <meta> | <metadata>)* <body> or <context> or <switch>


Name Value Description
id It may receive any string value that begins with a letter or an underscore and that only contains letters, digits, “.”, and “_”. The id attribute uniquely identifies the element within a document.
refer IDREF or the string “alias#id” where “id” is an IDREF value.

The refer attribute refers to an element id that will be reused. An element that refers to another element cannot be reused; that is, its id value cannot be the value of any refer attribute. The referred element must be a <context> or an imported <body> element.

The referred element and the element that refers to it must be considered the same regarding their data specification.

If the referred node (<context> or <body> element) is defined within an imported document D, the refer attribute value must have the format “alias#id”, where “alias” is the value of the alias attribute associated with the imported D document.

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