Re: axes in XPath patterns

The pattern syntax in XSLT 1.0 and XSLT 2.0, for no good reason at all, allows
the "//" pseudo-operator but does not allow *explicit* use of the descendant
or descendant-or-self axes.

This is fixed in 3.0, which allows all the downward axes to be used.

Michael Kay
Saxonica

> On 1 Mar 2017, at 16:29, Birnbaum, David J djbpitt@xxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Dear XSL-list,
>
> If I9ve understood correctly, the only axes supported in an XPath pattern
> in XSLT 2.0 are the child and the attribute axes. For that reason, a
> construction like:
>
> 	<xsl:template match="paragraph/descendant::inner">
>
> should raise an error, as it does in <oXygen/>. But I was surprised to see
> that the following construction:
>
> 	<xsl:template match="paragraph//inner">
>
> does not raise an error in <oXygen/>. According to Michael Kay, p. 627,
> paragraph//inner should be equivalent to
> paragraph//descendant-or-self::node()/child::inner, so it does appear to
> use an axis other than the child or attribute axis.
>
> I don't know how to reconcile this discrepancy with the general
> prohibition against using axes other than child or attribute in an XPath
> pattern in XSLT 2.0. Shouldn't both of the patterns above raise the same
> type of error?
>
>
> Thanks,
>
> David