exists($B/ancestor-or-self::*[. is $A])

Michael Kay
Saxonica

> On 14 Jun 2018, at 13:22, Costello, Roger L. costello@xxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hi Folks,
>
> The variable $A contains an element.
>
> The variable $B contains an element.
>
> I need an XPath expression that determines if $B is not contained in $A.
>
> This XPath expression seems to work:
>
>    not(index-of($B/ancestor::*,$A))
>
> but that seems awful, i.e., not straightforward, convoluted, and probably
inefficient.
>
> Is there a better (simpler, straightforward, efficient) XPath expression?
>
> /Roger