Simple Question

[Mike King]

What is the XPath expression that selects the value attribute in the
following xml?

<?xml version="1.0"?>
<root xmlns="http://a/" xmlns:a="http://a/">
<child a:value="1"/>
</root>

 

[Joris Gillis]

What is the XPath expression that selects the value attribute in the
following xml?

<?xml version="1.0"?>
<root xmlns="http://a/" xmlns:a="http://a/">
<child a:value="1"/>
</root>

//a:child/@a:value

with the prefix 'a' bound to namespace 'http://a/'

regards,

 

[David Carlisle]

What is the XPath expression that selects the value attribute in the
following xml?

/a:root/a:child/@a:value

where a is bound to "http://a/" either using
xmlns:a="http://a/"
in XSLT or via a setting in your XPath API.

David

 

[Mike King]

//a:child/@a:value

with the prefix 'a' bound to namespace 'http://a/'

regards,

I tried that, and it didn't work. What's wrong with my XSLT.

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:a="http://a/">
<xsl:template match="@a:value">
found
</xsl:template>
</xsl:stylesheet>

 

[Joris Gillis]

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:a="http://a/">
<xsl:template match="@a:value">
found
</xsl:template>
</xsl:stylesheet>

The problem here is that attribute nodes are not applied by default.
An equivalent of the built-in template rule in XSLT1.0:
<xsl:template match="*|/">
<xsl:apply-templates select="node()"/>
</xsl:template>

In order to let your xslt work, add this template:
<xsl:template match="*|/">
<xsl:apply-templates select="node()|@*"/>
</xsl:template>
but this will likely result in other unwanted behaviour.


regards,

 

[David Carlisle]

I tried that, and it didn't work. What's wrong with my XSLT.

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:a="http://a/">
<xsl:template match="@a:value">
found
</xsl:template>
</xsl:stylesheet>

A template only does anything if you apply templates to the matching
node, and that stylesheet doesn't apply templates to attribute nodes, so
no template natching an attribute will be executed.

the default templates for / and elements apply templates to child nodes
(only) not to attribute or namespace nodes. This is why an empty
stylesheet produces all element content (but not attribute content)

add

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

David

 

[Mike King]

A template only does anything if you apply templates to the matching

node, and that stylesheet doesn't apply templates to attribute nodes, so
no template natching an attribute will be executed.

the default templates for / and elements apply templates to child nodes
(only) not to attribute or namespace nodes. This is why an empty
stylesheet produces all element content (but not attribute content)

add

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

David

Ok then won't the following match as a template?

a:child/@a:value

 

[Joris Gillis]

Ok then won't the following match as a template?

a:child/@a:value

No,

The pattern '@a:value' isn't matched, so the same pattern with an extra
restriction (only 'value' attributes with a 'child' parent) will certainly
not match more.

But you can do this:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:s="s" xmlns:w="vv" xmlns:abc="abc"
version="1.0" xmlns:a="http://a/">

<xslutput method="xml" indent="yes"/>

<xsl:template match="a:root">
<xsl:apply-templates select="a:child/@a:value"/>
</xsl:template>

<xsl:template match="a:child/@a:value ">
match
</xsl:template>

</xsl:stylesheet>

 

[Mike King]

No,

The pattern '@a:value' isn't matched, so the same pattern with an extra
restriction (only 'value' attributes with a 'child' parent) will certainly
not match more.

But you can do this:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:s="s" xmlns:w="vv" xmlns:abc="abc"
version="1.0" xmlns:a="http://a/">

<xslutput method="xml" indent="yes"/>

<xsl:template match="a:root">
<xsl:apply-templates select="a:child/@a:value"/>
</xsl:template>

<xsl:template match="a:child/@a:value ">
match
</xsl:template>

</xsl:stylesheet>

I'm starting to understand now. XSLT is like a push-model where the
XSL/XSLT processor *must* be told to look for a specific pattern, not that
it's recursively going through the tree structure looking for a matching
pattern.

 

[Joris Gillis]

I'm starting to understand now. XSLT is like a push-model where the
XSL/XSLT processor *must* be told to look for a specific pattern, not
that it's recursively going through the tree structure looking for a
matching
pattern.

The xslt processor has to be told (with <xsl:apply-templates/>) to dive
further into the source tree, but there are built in templates.
http://www.w3.org/TR/xslt.html#built-in-rule
The built-in templates make the XLST processor go through all nodes,
except attribute nodes.