This shows you the differences between two versions of the page.
— |
switch [2014/09/16 14:26] (current) |
||
---|---|---|---|
Line 1: | Line 1: | ||
+ | ===== The <switch> Element ===== | ||
+ | ==== Definition and Usage ==== | ||
+ | |||
+ | The [[switch|<switch>]] element allows for defining alternative objects | ||
+ | (represented by [[media|<media>]], [[context|<context>]] or other [[switch|<switch>]] | ||
+ | elements) to be presented. The choice is madeduring presentation time. | ||
+ | |||
+ | Test rules used to choose the switch’schild component to be presented are | ||
+ | defined by [[rule|<rule>]] and [[compositerule|<compositeRule>]] elements; [[bindrule|<bindRule>]] | ||
+ | child elements associate these rules to child component objectsof the | ||
+ | [[switch|<switch>]] element. | ||
+ | |||
+ | A [[switchport|<switchPort>]] child element may define a mapping to a subset of the | ||
+ | switch’s child components. When a link is bound to a [[switchport|<switchPort>]] | ||
+ | element,the rules bound to mapped components are evaluated in the order they | ||
+ | are defined. The first rule evaluated as true determines the chosen object. | ||
+ | Ifall rules bound to mapped components are evaluated as false, a default | ||
+ | component, defined by the [[defaultcomponent|<defaultComponent>]]child element,is chosen; if | ||
+ | the [[defaultcomponent|<defaultComponent>]] element is not defined, no component is selected | ||
+ | for presentation and the NCL player behaves as if the selected component | ||
+ | does not exist. | ||
+ | |||
+ | All references to a switch’s child component are made through | ||
+ | [[switchport|<switchPort>]] elements or, by default, to the [[switch|<switch>]] element | ||
+ | without specifying any [[switchport|<switchPort>]]. In this case, it is considered as | ||
+ | if the reference is made to a default [[switchport|<switchPort>]] that contains | ||
+ | mapping elements to each child object of the switch and referring to its | ||
+ | whole content anchor. | ||
+ | |||
+ | From the moment a [[switch|<switch>]] is evaluated, it is considered resolved | ||
+ | until the end of the current switch presentation. | ||
+ | |||
+ | The [[switch|<switch>]] element may refer to another [[switch|<switch>]] element. In | ||
+ | this case, it has the same specification of the referred element. | ||
+ | |||
+ | ==== Syntax ==== | ||
+ | ^ Element ^ Attributes ^ Content ^ Parent ^ | ||
+ | | [[switch|<switch>]] | __//id//__, //refer// | ([[defaultcomponent|<defaultComponent>]]?, ([[switchport|<switchPort>]] <nowiki>|</nowiki> [[bindrule|<bindRule>]] <nowiki>|</nowiki> [[media|<media>]] <nowiki>|</nowiki> [[context|<context>]] <nowiki>|</nowiki> [[switch|<switch>]])*) | [[body|<body>]] or [[context|<context>]] or [[switch|<switch>]] | | ||
+ | ==== Attributes ==== | ||
+ | |||
+ | ^ 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. | <html><p></html>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// cannot be reused; that is, its //id// cannot be the value of any //refer// attribute. The referred element shall be a [[switch|<switch>]] element.<html></p></html><html><p></html>The referred element and the element that refers to it shall be considered the same only regarding their data specification.<html></p></html><html><p></html>If the referred node is defined within an imported document D, the //refer// attribute value shall have the format "alias#id", where "alias" is the value of the //alias// attribute associated with the imported component D.<html></p></html> | | ||
+ | |||
+ | |||
+ | |||