xsl:on-empty

Used to allow conditional content construction to be made streamable. Outputs the enclosed content only if the containing sequence also generates "ordinary" content.

Category: instruction
Content: sequence-constructor
Permitted parent elements: any XSLT element whose content model is sequence-constructor; any literal result element

Attributes

select?

expression

Notes on the Saxon implementation

New in XSLT 3.0, and implemented since Saxon 9.7.

Examples

The following code generates substitute text when there is no content, however it is not guaranteed-streamable because it processes child item-for-sale elements more than once:

<xsl:apply-templates select="item-for-sale"/> <xsl:if test="empty(item-for-sale)"> <p>There are no items for sale.</p> </xsl:if>

To make this streamable, it can be rewritten using the xsl:on-empty instruction:

<xsl:sequence> <xsl:apply-templates select="item-for-sale"/> <xsl:on-empty> <p>There are no items for sale.</p> </xsl:on-empty> </xsl:sequence>

Links to W3C specifications

XSLT 3.0 Specification