Combining XML elements with XSL

[mikea_59]

I am having trouble combining similar elements. Elements can be
combined if they have the same name and the same attribute values. I
can handle single level elements but am having problems with
multi-level elments (level of element nesting is unbound). I cannot
rely on fixed element names in the translator code since the translator
will be general purpose, elements names are not fixed.

Example input

<test>
<A x="0">
<B>1</B>
</A>
<A x="0">
<C>2</C>
</A>
<A x="0">
<D x="0">
<E>3</E>
</D>
</A>
<A x="0">
<D x="0">
<E>3</E>
</D>
</A>
<A x="0">
<D x="1">
<E>5</E>
</D>
</A>
<A x="1">
<B>4</B>
</A>
</test>

example output:

<test>
<A x="0">
<B>1</B>
<C>2</C>
<D x="0">
<E>3</E>
</D>
<D x="1">
<E>5</E>
</D>
</A>
<A x="1">
<B>4</B>
</A>
</test>

Any help would be greatly appreciated - still an XSL newbie

[Joris Gillis]

Re: Combining XML elements with XSL

On 15 Feb 2005 13:50:10 -0800, mikea_59 <mikea_59@yahoo .com> wrote:
[color=blue]
> I am having trouble combining similar elements. Elements can be
> combined if they have the same name and the same attribute values. I
> can handle single level elements but am having problems with
> multi-level elments (level of element nesting is unbound). I cannot
> rely on fixed element names in the translator code since the translator
> will be general purpose, elements names are not fixed.[/color]
Hi,

I'm afraid you'll have to use an 'xx:node-set' extension function to solve
this (in XSLT1.0).

Here's one solution (tested with Saxon), gives correct output for your
input.


<xsl:styleshe et xmlns:xsl="http ://www.w3.org/1999/XSL/Transform"
version="1.0" xmlns:exsl="htt p://exslt.org/common"
extension-element-prefixes="exsl" >

<xsl:output method="xml" indent="yes"/>

<xsl:strip-space elements="*"/>
<xsl:key name="element" match="*" use="concat(loc al-name(),@*)"/>

<xsl:template match="*">
<xsl:copy>
<xsl:copy-of select="@*"/>
<xsl:variable name="set">
<xsl:copy-of select="key('el ement',concat(l ocal-name(),@*))/*"/>
</xsl:variable>
<xsl:apply-templates select="text()"/>
<xsl:apply-templates
select="exsl:no de-set($set)/*[generate-id()=generate-id(key('element ',concat(local-name(),@*)))]"/>
</xsl:copy>
</xsl:template>

</xsl:stylesheet>

regards,
Joris Gillis
--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

[mikea_59]

Re: Combining XML elements with XSL


That worked - thanks a lot! What a great NG.

So, is this strictly a 1.0 solution? Doesn't 2.0 eliminate the need
to use node-set() by enabling temporary templates? Is node-set() even
available in 2.0 - in Saxon? How would I change this for 2.0?

Sorry for all the ???

Thanks again
mikea

[Joris Gillis]

Re: Combining XML elements with XSL

On 17 Feb 2005 11:56:09 -0800, mikea_59 <mikea_59@yahoo .com> wrote:
[color=blue]
> So, is this strictly a 1.0 solution?[/color]
Everything that can be achieved in XSLT1.0 certainly can in XSLT2.0, isn't
that logic;)
[color=blue]
> Doesn't 2.0 eliminate the need
> to use node-set() by enabling temporary templates?[/color]
Excerpt form the latest XSLT2.0 working draft:
"The result tree fragment data-type is eliminated. A variable-binding
element with content (and no as attribute) now constructs a temporary
tree, and the value of the variable is the root node of this tree (see 9.3
Values of Variables and Parameters). With an as attribute, a
variable-binding element may be used to construct an arbitrary sequence.
These features eliminate the need for the xx:node-set extension function
provided by many XSLT 1.0 implementations ."
[color=blue]
> available in 2.0 - in Saxon? How would I change this for 2.0?[/color]

I don't have experience with 2.0, but I guess writing '$set' in stead of
'exsl:node-set($set)' will do...


regards,
Joris Gillis
--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

[mikea_59]

Re: Combining XML elements with XSL


Joris Gillis wrote:[color=blue]
> On 17 Feb 2005 11:56:09 -0800, mikea_59 <mikea_59@yahoo .com> wrote:
>[color=green]
> > So, is this strictly a 1.0 solution?[/color]
> Everything that can be achieved in XSLT1.0 certainly can in XSLT2.0,[/color]
isn't[color=blue]
> that logic;)[/color]

Yes, very logical, but when I set stylesheet to version=2.0 and
re-run the translation in Saxon, I get an error:

"A sequence of more than one item is not allowed as the first
argument of generate-id()"

I guess it's not related to node-set()
[color=blue]
>[color=green]
> > Doesn't 2.0 eliminate the need
> > to use node-set() by enabling temporary templates?[/color]
> Excerpt form the latest XSLT2.0 working draft:
> "The result tree fragment data-type is eliminated. A variable-binding[/color]
[color=blue]
> element with content (and no as attribute) now constructs a temporary[/color]
[color=blue]
> tree, and the value of the variable is the root node of this tree[/color]
(see 9.3[color=blue]
> Values of Variables and Parameters). With an as attribute, a
> variable-binding element may be used to construct an arbitrary[/color]
sequence.[color=blue]
> These features eliminate the need for the xx:node-set extension[/color]
function[color=blue]
> provided by many XSLT 1.0 implementations ."
>[color=green]
> > available in 2.0 - in Saxon? How would I change this for 2.0?[/color]
>
> I don't have experience with 2.0, but I guess writing '$set' in stead[/color]
of[color=blue]
> 'exsl:node-set($set)' will do...
>
>
> regards,
> Joris Gillis
> --
> Using Opera's revolutionary e-mail client: http://www.opera.com/m2/[/color]

[Joris Gillis]

Re: Combining XML elements with XSL

On 17 Feb 2005 13:21:49 -0800, mikea_59 <mikea_59@yahoo .com> wrote:
[color=blue]
> "A sequence of more than one item is not allowed as the first
> argument of generate-id()"[/color]

Really? Then they have changed the behaviour of generate-id().

Solution:
change
<xsl:apply-templates
select="exsl:no de-set($set)/*[generate-id()=generate-id(key('element ',concat(local-name(),@*)))]"/>
into
<xsl:apply-templates
select="exsl:no de-set($set)/*[generate-id()=generate-id(key('element ',concat(local-name(),@*))[1])]"/>

--
Using Opera's revolutionary e-mail client: http://www.opera.com/m2/

[David Carlisle]

Re: Combining XML elements with XSL

[color=blue]
> Really? Then they have changed the behaviour of generate-id().[/color]

it's a more or less pervasive change, as part of the stricter tying
introduced in 2 most instances of functions that expect a single node
complain if given more than one node rather than silently taking the
first in doc order.

David

[mikea_59]

Re: Combining XML elements with XSL


It looks like that did the trick, thanks a lot. I'm still not sure I
follow the syntax of the select attribute, I guess I'll go back to my
Kay book...

Thanks again,
mikea

[Joris Gillis]

Re: Combining XML elements with XSL

Tempore 23:15:45, die Thursday 17 February 2005 AD, hinc in foro {comp.text.xml} scripsit mikea_59 <mikea_59@yahoo .com>:
[color=blue]
>
> It looks like that did the trick, thanks a lot. I'm still not sure I
> follow the syntax of the select attribute[/color]

you mean this line?

<xsl:apply-templates select="$set/*[generate-id()=generate-id(key('element ',concat(local-
name(),@*))[1])]"/>

well, the trick is to let the xslt processor create a key lookup table based on the node-set in the variable in stead of a lookup table indexing all nodes in the input XML document.

The 'generate-id()' + 'key()' stuff is just basic Muenchian grouping technique...

--
Joris Gillis (http://www.ticalc.org/cgi-bin/acct-v...i?userid=38041)
"ΦιλÎ ®ÎºÎ¿Î¿à ŽÂ½ εινΠ±ÃŽÂ¹ μαλΠ»ÃŽÂ¿ÃŽÂ½ η φιλόΠ»ÃŽÂ±ÃŽÂ»ÃŽÂ¿ÃŽ ½" - Κλεϊ’βουà ŽÂ»ÃŽÂ¿Ãâ€š