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RE: RE: variable binding

2003-11-06 07:29:13
Let's look at your template:

<xsl:template match="s//ng//*[1]" priority="5">
  <xsl:variable name="branch">right</xsl:variable>
  <xsl:copy>
    <xsl:attribute name="branch"><xsl:value-of 
select="$branch"/></xsl:attribute>
    <xsl:apply-templates select="@*|node()"/>
  </xsl:copy>
</xsl:template>

Inside this template you declare the variable first. This variable is then 
in-scope for all following siblings *of the variable*  and to any descendants 
of the following siblings.

$branch is in-scope for <xsl:apply-templates select="@*|node()"/>, but you 
don't refer to it in this element. Instead, you refer to it in a template that 
is a following-sibling of the variable's parent element that happens to be 
called by <xsl:apply-templates select="@*|node()"/>.

I am confused by " ... I am trying to find the leftmost daughter of the element 
ng." XPath has no concept of left or right. It has three (if we ignore the 
attribute axis) broad categories of axes: sibling axis, ancestor axis and 
descendant axis. 

Are you saying that you want to find an element that is a child of <ng>? XPath 
has a "child axis" that is a kind of descendant axis that includes only those 
elements that are one level down from the parent element. 

Please try to re-state your requirement using XPath terminology, or tell us 
which specific element in you example fits your requirement so we can figure 
out the correct XPath expression to select it.
-- 
Charles Knell
cknell(_at_)onebox(_dot_)com - email



-----Original Message-----
From:     Shipra Dingare <sdingar1(_at_)inf(_dot_)ed(_dot_)ac(_dot_)uk>
Sent:     Thu, 6 Nov 2003 11:21:49 +0000 (GMT)
To:       xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject:  RE: [xsl] variable binding


So then what does it mean to say that "variable bindings declared in 
templates should be visible to descendants and following siblings"? 
This is what it says in the specs.

Also, the whole reason I wanted to do this was because I am trying to find 
the leftmost daughter of the element ng.
Is there a way to do this?  I have really thought about it a lot but can't 
seem to find anything workable.
-Shipra



On Wed, 5 Nov 2003, Michael Kay wrote:


I'm having trouble with variable binding - basically, I read 
that variable 
bindings declared in templates should be visible to descendants and 
following siblings, but I'm getting not getting the behavior 
I thought I 
would with my stylesheet using Saxon 6.5.2...

You've misunderstood the rules. The scope of variables is static, not
dynamic. It doesn't depend on your source document, and it doesn't
depend on the way in which templates call each other. You're trying to
reference a variable in one template that's declared in a different
template. What you need to do is pass the value as a parameter from one
template to the other, using xsl:with-param and xsl:param.

Michael Kay



so the relevant part of my file looks like this (it's a 
subbranch of s):
          <ng of='proteins' role='h'>
                <nx head='targeting' role='h'>
                     <W index='92'>the</W>
                     <W role='h' index='93'>targeting</W>
                </nx>
                     <W index='94'>of</W>
                <nx head='proteins' role='k'>
                     <W index='95'>the</W>
                     <W index='96'>myosin</W>
                     <W role='h' index='97'>proteins</W>
                </nx>
    </ng>

and my stylesheet looks like this:

<xsl:template match="@* | * | comment() | processing-instruction() | 
node()">
 <xsl:copy>
  <xsl:apply-templates select="@*|node()"/>
 </xsl:copy>
</xsl:template>

<xsl:template match="s//ng//*[1]" priority="5">
    <xsl:variable name="branch">right</xsl:variable>
    <xsl:copy>
    <xsl:attribute name="branch"><xsl:value-of 
select="$branch"/></xsl:attribute>
    <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
</xsl:template>


<xsl:template match="s//ng//*" priority="4">
    <xsl:copy>
    <xsl:attribute name="branch"><xsl:value-of 
select="$branch"/></xsl:attribute>
    <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
</xsl:template>

but when I try to run it, it tells me that the variable 
branch has not 
been declared, even though it should first have processed the first 
daughter of ng, where it has been declared. 

Best,
shipra


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