Remove parent element if there are no children

[CI]

I have the following XML file

<Book>
<Chapters>
<Chapter number="1"/>
<Chapter number="2"/>
</Chapters>
<Colors>
<Color RGB="255"/>
<Color RGB="211" name="Red"/>
<Color name="Yellow"/>
<Color RGB="127"/>
</Colors>
</Book>

I want to get a tree with the <Colorelement s that don't have RGB
attribute:

So I came up with this XSLT sheet.

<?xml version="1.0" encoding="UTF-8"?>
<xsl:styleshe et version="1.0" xmlns:xsl="http ://www.w3.org/1999/XSL/
Transform">
<xsl:template match="@*|node( )">
<xsl:copy>
<xsl:apply-templates select="@*|node ()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="Color">

<xsl:choose>
<xsl:when test="@RGB">

</xsl:when>
<xsl:otherwis e>
<xsl:copy-of select="."/>
</xsl:otherwise>
</xsl:choose>

</xsl:template>

</xsl:stylesheet>

It works correctly, but if in my XML file all the <Colorelement s
have RGB attribute the resulted tree
contains empty <Colors></Colorsnode.

Anyone had an idea how to conditionally remove it?

Regards,

Michael

[Joseph Kesselman]

Anyone had an idea how to conditionally remove it?

Adding a check for no-children-exist to your RGB-attribute-exists test
ought to do it, right?


--
Joe Kesselman / Beware the fury of a patient man. -- John Dryden

[Joseph Kesselman]

<Colors>

<Color RGB="255"/>
<Color RGB="211" name="Red"/>
<Color name="Yellow"/>
<Color RGB="127"/>
</Colors>

It works correctly, but if in my XML file all the <Colorelement s
have RGB attribute the resulted tree
contains empty <Colors></Colorsnode.

Anyone had an idea how to conditionally remove it?

Don't think about "removing", think about "not copying".

You want to copy the <Colorselemen t only if it contains something
other than a <Colorelement with an RGB attribute.

Complication: Removing the <Colorelement s from the above example does
NOT make <Colorsempty, even if you remove Yellow -- because it still
contains the whitespace text nodes between the elements.

It's possible to solve this in a single pass, but I think it's going to
be ugly. You may want to think about making it simpler by running a
second stylesheet that removes <Colorselemen ts that contain only
whitespace... or, if you're willing to rely on the nodeset extensions,
running two passes within a single stylesheet by first styling part or
all of the document into a variable and then styling from the variable
to your actual output. Look for examples of use of the exslt:node-set
extension for information about how to do this.


--
Joe Kesselman / Beware the fury of a patient man. -- John Dryden

[CI]

On Apr 13, 4:59 pm, Joseph Kesselman <keshlam-nos...@comcast. net>
wrote:

<Colors>
<Color RGB="255"/>
<Color RGB="211" name="Red"/>
<Color name="Yellow"/>
<Color RGB="127"/>
</Colors>
It works correctly, but if in my XML file all the <Colorelement s
have RGB attribute the resulted tree
contains empty <Colors></Colorsnode.

Anyone had an idea how to conditionally remove it?

Don't think about "removing", think about "not copying".

You want to copy the <Colorselemen t only if it contains something
other than a <Colorelement with an RGB attribute.

Complication: Removing the <Colorelement s from the above example does
NOT make <Colorsempty, even if you remove Yellow -- because it still
contains the whitespace text nodes between the elements.

It's possible to solve this in a single pass, but I think it's going to
be ugly. You may want to think about making it simpler by running a
second stylesheet that removes <Colorselemen ts that contain only
whitespace... or, if you're willing to rely on the nodeset extensions,
running two passes within a single stylesheet by first styling part or
all of the document into a variable and then styling from the variable
to your actual output. Look for examples of use of the exslt:node-set
extension for information about how to do this.

--
Joe Kesselman / Beware the fury of a patient man. -- John Dryden

Thanks Joe, I appreciate it.

I posted this problem to another group and Dimitre Novatchev
suggested the following stylesheet:

------------------------------------------------------------------------------------------
<xsl:styleshe et version="1.0"
xmlns:xsl="http ://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="ye s" indent="yes"/>

<xsl:strip-space elements="*"/>

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

<xsl:template match="Colors[not(Color[not(@RGB)])]"/>
<xsl:template match="Color[@RGB]"/>
</xsl:stylesheet>
------------------------------------------------------------------------------

Regards,

Michael

[Joe Kesselman]

CI wrote:

<xsl:template match="Colors[not(Color[not(@RGB)])]"/>

OK, that will certainly discard <Colorselemen ts that do not contain a
<Colorwhich does not have the RGB attribute. If the only things that
will be in <Colorsis <Colorelement s and whitespace, that should
work. If there's anything else which might appear there, you may wind up
deleting some elements that you wanted to keep.

--
() ASCII Ribbon Campaign | Joe Kesselman
/\ Stamp out HTML e-mail! | System architexture and kinetic poetry

[Dimitre Novatchev]

"Joe Kesselman" <ke************ @comcast.netwro te in message
news:RK******** *************** *******@comcast .com...

CI wrote:

> <xsl:template match="Colors[not(Color[not(@RGB)])]"/>

OK, that will certainly discard <Colorselemen ts that do not contain a
<Colorwhich does not have the RGB attribute. If the only things that
will be in <Colorsis <Colorelement s and whitespace, that should work.

Of course, and this is exactly what the OP wanted! :o)
Cheers,
Dimitre Novatchev

[p.lepin]

On Apr 14, 3:46 am, "CI" <mdani...@yahoo .comwrote:

On Apr 13, 4:59 pm, Joseph Kesselman
<keshlam-nos...@comcast. netwrote:

[...]

It works correctly, but if in my XML file all the
<Colorelement s have RGB attribute the resulted tree
contains empty <Colors></Colorsnode. Anyone had an
idea how to conditionally remove it?

Don't think about "removing", think about "not
copying".

[...]

I posted this problem to another group and Dimitre
Novatchev suggested the following stylesheet:

<xsl:template match="Colors[not(Color[not(@RGB)])]"/>
<xsl:template match="Color[@RGB]"/>

This is a very clean and neat solution,--which is hardly
surprising,--but I always cringe a bit when I have to
express the same thing twice in the code. The following
looks a bit scarier, but has what counts as virtue with me:
it's re-uses the condition that both your rules are
dependent upon:

<xsl:styleshe et version="1.0"
xmlns:xsl="http ://www.w3.org/1999/XSL/Transform">
<xsl:template match="@*|node( )">
<xsl:copy>
<xsl:apply-templates select="@*|node ()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="Colors">
<xsl:variable name="color-elements"
select="Color[not(@RGB)]"/>
<xsl:if test="$color-elements">
<xsl:copy>
<xsl:apply-templates select="$color-elements"/>
</xsl:copy>
</xsl:if>
</xsl:template>
</xsl:stylesheet>

YMMV.

--
Pavel Lepin

[p.lepin]

On Apr 14, 10:22 am, p.le...@ctncorp .com wrote:

On Apr 14, 3:46 am, "CI" <mdani...@yahoo .comwrote:

On Apr 13, 4:59 pm, Joseph Kesselman
<keshlam-nos...@comcast. netwrote:

It works correctly, but if in my XML file all the
<Colorelement s have RGB attribute the resulted
tree contains empty <Colors></Colorsnode. Anyone
had an idea how to conditionally remove it?

Don't think about "removing", think about "not
copying".

I posted this problem to another group and Dimitre
Novatchev suggested the following stylesheet:

This is a very clean and neat solution,--which is hardly
surprising,--but I always cringe a bit when I have to
express the same thing twice in the code. The following
looks a bit scarier, but has what counts as virtue with me:
it's re-uses the condition that both your rules are
dependent upon:

On a side note, XSLT2 is bliss:

<xsl:styleshe et version="2.0"
xmlns:xsl="http ://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:variable name="post-pass-1">
<xsl:apply-templates mode="pass-1"/>
</xsl:variable>
<xsl:apply-templates select="$post-pass-1"
mode="pass-2"/>
</xsl:template>
<xsl:template match="@*|node( )" mode="pass-1">
<xsl:copy>
<xsl:apply-templates select="@*|node ()"
mode="pass-1"/>
</xsl:copy>
</xsl:template>
<xsl:template match="Color[@RGB]" mode="pass-1"/>
<xsl:template match="@*|node( )" mode="pass-2">
<xsl:copy>
<xsl:apply-templates select="@*|node ()"
mode="pass-2"/>
</xsl:copy>
</xsl:template>
<xsl:template match="Colors[not(*)]" mode="pass-2"/>
</xsl:stylesheet>

--
Pavel Lepin

[Joe Kesselman]

p.*****@ctncorp .com wrote:

On a side note, XSLT2 is bliss:

A minor change, but a good one: XSLT removed the distinction between
Result Tree Fragments and Node Sets (both are now grouped together as
Temporary Trees), so one doesn't need the node-set extension to convert
the former into the latter.

Outside of that, this is the same two-past solution I suggested.

--
() ASCII Ribbon Campaign | Joe Kesselman
/\ Stamp out HTML e-mail! | System architexture and kinetic poetry

[Joe Kesselman]

Dimitre Novatchev wrote:

Of course, and this is exactly what the OP wanted! :o)

Granted. But I tend to practice defensive programming, so I look for the
maximally robust solution...
--
() ASCII Ribbon Campaign | Joe Kesselman
/\ Stamp out HTML e-mail! | System architexture and kinetic poetry