FunctX XSLT Functions

FunctX XSLT Function Library > Atomic Values of All Types > Boolean >

fn:boolean

The effective boolean value of a sequence

Description

The fn:boolean function calculates the effective boolean value of a sequence. In most cases it is unnecessary to call this function because the effective boolean value is calculated automatically in many expressions, including conditional and logical expressions, where clauses, and predicates.

This description is © Copyright 2007, O'Reilly Media. It is excerpted from the book XQuery by Priscilla Walmsley, O'Reilly, 2007. For a complete explanation of this function, please refer to Appendix A of the book.

Arguments and Return Type

Name	Type
`$arg`	`item()*`
return value	`xs:boolean`

Examples

<xsl:variable name="ordDoc" select="doc('http://www.functx.com/input/order.xml')"/>

XSLT Example	Results
`boolean( () )`	`false`
`boolean('')`	`false`
`boolean(0)`	`false`
`boolean('0')`	`true`
`boolean('false')`	`true`
`boolean(xs:float('NaN'))`	`false`
`boolean((false(), false(), false()))`	Error FORG0006
`boolean($ordDoc/order[1])`	`true`
`boolean($ordDoc/noSuchChild)`	`false`

History

Published On	Last Updated	Contributor(s)
2006-06-27	2007-02-26	W3C, XQuery 1.0 and XPath 2.0 Functions and Operators, http://www.w3.org/TR/xpath-functions/

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