FunctX XQuery Functions

FunctX XQuery Function Library > XML Nodes > Document Order >

functx:precedes-not-ancestor

Whether an XML node precedes another without being its ancestor

Description

The functx:precedes-not-ancestor function returns a boolean value indicating whether $a precedes $b without being its ancestor. If either argument is the empty sequence the function returns false.

Arguments and Return Type

Name	Type	Description
`$a`	`node()?`	the first node
`$b`	`node()?`	the second node
return value	`xs:boolean`

XQuery Function Declaration

See XSLT definition.

declare namespace functx = "http://www.functx.com";
declare function functx:precedes-not-ancestor
  ( $a as node()? ,
    $b as node()? )  as xs:boolean {

   $a << $b and empty($a intersect $b/ancestor::node())
 } ;

Examples

`let $in-xml :=`	<authors> <author> <fName>Kate</fName> <lName>Jones</lName> </author> <author> <fName>John</fName> <lName>Doe</lName> </author> </authors>
`return`

XQuery Example

Results

functx:precedes-not-ancestor(
     $in-xml//author[1],$in-xml//author[2])

true

functx:precedes-not-ancestor(
     $in-xml//author[1],
     $in-xml//author[1]/fName)

false

functx:precedes-not-ancestor(
     $in-xml//author[2],$in-xml//author[1])

false

History

Published On	Last Updated	Contributor(s)
2006-06-27	2007-02-26	W3C XML Query Working Group, XQuery 1.0: An XML Query Language, http://www.w3.org/TR/xquery/(name was changed from precedes to precedes-not-ancestor for clarity)

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