zero-or-one

Tests whether $srcval contains zero or one items; fails if it contains multiple items.

zero-or-one($arg as item()*) ➔ item()?

Arguments
	$arg	item()*	The input sequence to be tested
Result		item()?

Links to W3C specifications

Namespace: http://www.w3.org/2005/xpath-functions

Applies to: XPath 2.0, XSLT 2.0, XQuery 1.0 and later versions

XPath 2.0 Functions and Operators

XPath 3.0 Functions and Operators

Notes on the Saxon implementation

The function is fully implemented according to the W3C specifications.