Re: The order of selected nodes in a select pattern with OrExpressions?

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 99/01/24 15:52 -0500, Tyler Baker wrote:
>One thing that does not seem to be clear in the XSL in the XSL draft is
>in what order the nodes should be selected in a select expression with
>or expressions present.

According to production [1]:

A select pattern must match the production for SelectExpr; it returns the
list of nodes that results from evaluating the SelectExpr with the current
node as context; the nodes are in the list are in document order.

However the select expression is constructed the expected result appears to
me to be explicit and unambiguous.  

I don't see any constraints, nor would I want any.  Consider your example,
if you had a mixture of multiple instantiations of the three elements <b1>,
<b2>, <b3>:

  <b1> <b3> <b2> <b3> <b1> <b3> <b2>

... and you wanted to interlink them as they arrived (as in a slide show),
you need them to arrive in document order.

>What if I have a template:
>
><xsl:template match=a>
>  <xsl:apply-templates select="b3 | b2 | b1">
></xsl:template>
>
>Should the output text be: cba, or should the output text be: abc.

It should be "abc".

If you wanted it to be cba, then you would do:

<xsl:template match="a">
  <xsl:apply-templates select="b3"/>
  <xsl:apply-templates select="b2"/>
  <xsl:apply-templates select="b1"/>
</xsl:template>

(setting aside issues of preserving the whitespace ... but I hope you can
see what I mean).

A full example is below ... I hope it helps.

......... Ken


T:\FTEMP>type test.xml
<?xml version="1.0"?>
<a>
  <b1>
    a
  </b1>
  <b2>
    b
  </b2>
  <b3>
    c
  </b3>
</a>

T:\FTEMP>type test.xsl
<xsl:stylesheet
       xmlns:xsl="http://www.w3.org/TR/WD-xsl";>
       
<xsl:template match="a">
  <xsl:text>
  Document Order:</xsl:text>
  <xsl:apply-templates select="b3 | b2 | b1"/>
  <xsl:text>
  Forced Order:</xsl:text>
  <xsl:apply-templates select="b3"/>
  <xsl:apply-templates select="b2"/>
  <xsl:apply-templates select="b1"/>
</xsl:template>

</xsl:stylesheet>
T:\FTEMP>call xsl test.xml test.xsl test.out
T:\FTEMP>type test.out

  Document Order:
    a
  
    b
  
    c
  
  Forced Order:
    c
  
    b
  
    a
  
T:\FTEMP>


--
G. Ken Holman         mailto:gkholman@xxxxxxxxxxxxxxxxxxxx
Crane Softwrights Ltd.  http://www.CraneSoftwrights.com/s/
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