[xsl] My first attempt at XSLT streaming -- it works! But why?

Hi Folks,

I have an XML document that contains a bunch of <Book> elements. I want my XSLT 
program to use streaming to count the number of Books. I mimicked the example 
in the XSLT spec, section 19.1.1 (Examples of xsl:stream). 

My XSLT program produced the correct result. Yea! But then I read this at the 
top of section 19.1.1 in the XSLT spec:

        These examples no longer work; it is no longer 
        possible to compute an aggregate over descendant 
        values using a path expression. Instead, traversal 
        using templates is required.

Hmm, apparently my XSLT program should not have worked. So why did it work?

What is the "right" way to write the streaming code?

I am using oXygen XML, which uses Saxon 9.5.0.2

Here is my XSLT program:

---------------------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
                xmlns:xs="http://www.w3.org/2001/XMLSchema";
                exclude-result-prefixes="#all"
                version="3.0">
    
    <xsl:output method="xml" />
    
    <xsl:template match="/">
        <xsl:stream href="BookCatalogue.xml">
            <count>
                <xsl:for-each select="BookCatalogue">
                    <xsl:iterate select="Book">
                        <xsl:param name="count" select="0" as="xs:decimal"/>
                        <xsl:next-iteration>
                            <xsl:with-param name="count" select="$count+1"/>
                        </xsl:next-iteration>
                        <xsl:on-completion>
                            <xsl:value-of select="$count"/>
                        </xsl:on-completion>
                    </xsl:iterate>
                </xsl:for-each>
            </count>
        </xsl:stream>
    </xsl:template>
    
</xsl:stylesheet>
---------------------------------------------------------

And here is my XML document:

---------------------------------------------------------
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="BookCatalogue.xsl"?>
<BookCatalogue>
        <Book>
                <Title>Six Great Ideas</Title>
                <Author>Mortimer J. Adler</Author>
                <Date>1981</Date>
                <ISBN>0-02-072020-3</ISBN>
                <Publisher>Macmillan Publishing Company</Publisher>
        </Book>
        <Book>
                <Title>Illusions</Title>
                <Author>Richard Bach</Author>
                <Date>1977</Date>
                <ISBN>0-440-34319-4</ISBN>
                <Publisher>Dell Publishing Co.</Publisher>
        </Book>
        <Book>
                <Title>The First and Last Freedom</Title>
                <Author>J. Krishnamurti</Author>
                <Date>1954</Date>
                <ISBN>0-06-064831-7</ISBN>
                <Publisher>Harper &amp; Row</Publisher>
        </Book>
</BookCatalogue>
---------------------------------------------------------

--~------------------------------------------------------------------
XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list
To unsubscribe, go to: http://lists.mulberrytech.com/xsl-list/
or e-mail: <mailto:xsl-list-unsubscribe(_at_)lists(_dot_)mulberrytech(_dot_)com>
--~--