On Thu, Oct 03, 2019 at 04:59:28PM -0000, Liam R. E. Quin liam@xxxxxxxxxxxxxxxx scripsit:
> While i was preparing for a course on XSLT 3 later this month, i
> wondered whether other people would have favourite features that were
> introduced in XSLT 3. I know i do.
> 
> What do you find most useful? Or like the best?

Maps.  I find maps are hands-down the single most useful thing in XSLT 3. (Even
if that's technically 3.1.)

xsl:mode can clearly do much more than I use it for, but the one-line
identity template version is a boon to multi-pass processing.

The general... compactness of expression?  I'm not sure what to call it.

<xsl:variable as="xs:integer" name="splitPos" select="min($kids[label = $labelKeys] ! index-of($kids, .))" /> 

is certainly *possible* in XSLT 1.0, but I'm pretty sure I couldn't
write it like that.  Possibly better phrased as "it's been awhile since
I was annoyed by the lack of function".

-- Graydon