Used to allow conditional content construction to be made streamable. Outputs the enclosed content only if the containing sequence also generates "ordinary" content.
Permitted parent elements: any XSLT element whose content model is sequence-constructor; any literal result element
Notes on the Saxon implementation
New in XSLT 3.0, and implemented since Saxon 9.7.
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:
To make this streamable, it can be rewritten using the