Re: [xsl] sorting by comparing two nodes

[Claus Nagel <claus_nagel@xxxxxx>]

> I am not all that clear on how you would sort these.

I try to implement a Graham scan to compute the convex hull of the
points.

> expr:= sqrt((x-$ref/x)^2+(y-$ref/y)^2)

thanks for your idea. but your expr just takes one point and the reference
point as the sorting key. my sorting key changes each time another pair of
points is compared.

well, what I need would be something like:
<xsl:for-each select="$points">
    <xsl:sort select="expr"/>
    --> to compute the expr I need to know the values af the actual point and
          the values of its predecessor.
</xsl:for-each>

I know I can't access the predecessor in a xsl:sort. But is there another
way to implement this? Well in the end it is just a normal quicksort with
a function which compares two elements and returns -1 or 0 or 1 to determine
the way of sorting.