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I have an XML file that I want to squeeze down as small as possible for
storage in an embedded device. I want it to still be a valid XML file
(and not something like a binary ASN.1 encoding of an XML file) but it
does not need to carry the long tags it currently has as long as I
create an XSLT which will put it back into the right form. What I had
in mind was something like this:

<original-xml-fragment>
<very-long-and-verbose-tag name="Long tag 1">
<more-information-is-stored-here name="stuff 1"/>
</very-long-and-verbose-tag>
<very-long-and-verbose-tag name="Long tag 2">
<more-information-is-stored-here name="stuff 2"/>
<valuable-additional-information name="foo"/>
</very-long-and-verbose-tag>
</original-xml-fragment>

I'm thinking of transforming it to this:

<o><v n="Long tag 1"><m n="stuff 1"/></v><v n="Long tag 2"><m n="stuff
2"/><v2 n="foo"/></v></o>

My question is, has someone already generated an XSLT that would
abbreviate tags in this kind of way AND generate the corresponding
"decoder" XSLT which would reconstitute the original. I have ideas
about how to do it using a procedural language, but I would like to do
it entirely with XSL transforms if I can.

The only part that I don't really know how to do is to automatically
generate short, unique abbreviations for each of the tags. I *could*
specify them all manually once, but I'd prefer an automatic solution to
simplify maintenance.

Ed

> I have an XML file that I want to squeeze down as small as possible for
> storage in an embedded device. I want it to still be a valid XML file
> (and not something like a binary ASN.1 encoding of an XML file) but it
> does not need to carry the long tags it currently has as long as I
> create an XSLT which will put it back into the right form. What I had
> in mind was something like this:
>
> <original-xml-fragment>
> <very-long-and-verbose-tag name="Long tag 1">
> <more-information-is-stored-here name="stuff 1"/>
> </very-long-and-verbose-tag>
> <very-long-and-verbose-tag name="Long tag 2">
> <more-information-is-stored-here name="stuff 2"/>
> <valuable-additional-information name="foo"/>
> </very-long-and-verbose-tag>
> </original-xml-fragment>
>
> I'm thinking of transforming it to this:
>
> <o><v n="Long tag 1"><m n="stuff 1"/></v><v n="Long tag 2"><m n="stuff
> 2"/><v2 n="foo"/></v></o>
>
> My question is, has someone already generated an XSLT that would
> abbreviate tags in this kind of way AND generate the corresponding
> "decoder" XSLT which would reconstitute the original. I have ideas
> about how to do it using a procedural language, but I would like to do
> it entirely with XSL transforms if I can.
>
> The only part that I don't really know how to do is to automatically
> generate short, unique abbreviations for each of the tags. I *could*
> specify them all manually once, but I'd prefer an automatic solution to
> simplify maintenance.

Hi,

I've created this little stylesheet that will map all unique nodes names and give them abbreviations. It might be handy as an intermediate step towards a solution for your - btw very interesting- question.

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlnssl="http://www.w3.org/1999/XSL/Transform">

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

<xsl:key name="name" match="*|@*" use="local-name()"/>

<xsl:template match="/">
<name-mapping>
<xsl:for-each select="//*[generate-id()=generate-id(key('name',local-name()))]|//@*[generate-id()=generate-id(key('name',local-name()))]">
<name>
<xsl:attribute name="s"><xsl:number value="position()" format="a"/></xsl:attribute>
<xsl:value-of select="local-name()"/>
</name>
</xsl:for-each>
</name-mapping>
</xsl:template>

</xsl:stylesheet>



this will generate the following output:

<name-mapping>
<name s="a">original-xml-fragment</name>
<name s="b">very-long-and-verbose-tag</name>
<name s="c">name</name>
<name s="d">more-information-is-stored-here</name>
<name s="e">valuable-additional-information</name>
</name-mapping>

regards,
--
Joris Gillis (http://www.ticalc.org/cgi-bin/acct-v...i?userid=38041)
Ceterum censeo XML omnibus esse utendum

>> My question is, has someone already generated an XSLT that would
>> abbreviate tags in this kind of way AND generate the corresponding
>> "decoder" XSLT which would reconstitute the original. I have ideas
>> about how to do it using a procedural language, but I would like to do
>> it entirely with XSL transforms if I can.
>>
>> The only part that I don't really know how to do is to automatically
>> generate short, unique abbreviations for each of the tags. I *could*
>> specify them all manually once, but I'd prefer an automatic solution to
>> simplify maintenance.
>
> this will generate the following output:
>
> <name-mapping>
> <name s="a">original-xml-fragment</name>
> <name s="b">very-long-and-verbose-tag</name>
> <name s="c">name</name>
> <name s="d">more-information-is-stored-here</name>
> <name s="e">valuable-additional-information</name>
> </name-mapping>
>
Hi, again

given that it is allowed to use two steps of tranformation, you can do this:
Unleash the above stylesheet on the verbose XML and let it output to a file named 'name-map.xml'.

When you apply the following stylesheet, the verbose XML will be reduced.

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlnssl="http://www.w3.org/1999/XSL/Transform">

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

<xsl:template match="*">
<xsl:variable name="name" select="local-name()"/>
<xsl:element name="{document('name-map.xml')//name[.=$name]/@s}">
<xsl:apply-templates select="@*"/>
<xsl:apply-templates/>
</xsl:element>
</xsl:template>

<xsl:template match="@*">
<xsl:variable name="name" select="local-name()"/>
<xsl:attribute name="{document('name-map.xml')//name[.=$name]/@s}">
<xsl:value-of select="."/>
</xsl:attribute>
</xsl:template>

</xsl:stylesheet>


The reduced form will look like this:
<a>
<b c="Long tag 1">
<d c="stuff 1"/>
</b>
<b c="Long tag 2">
<d c="stuff 2"/>
<e c="foo"/>
</b>
</a>


And this stylesheet will expand it again to the original verbose form:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0" xmlnssl="http://www.w3.org/1999/XSL/Transform">

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

<xsl:template match="*">
<xsl:variable name="name" select="local-name()"/>
<xsl:element name="{document('name-map.xml')//name[@s=$name]}">
<xsl:apply-templates select="@*"/>
<xsl:apply-templates/>
</xsl:element>
</xsl:template>

<xsl:template match="@*">
<xsl:variable name="name" select="local-name()"/>
<xsl:attribute name="{document('name-map.xml')//name[@s=$name]}">
<xsl:value-of select="."/>
</xsl:attribute>
</xsl:template>

</xsl:stylesheet>


I hope this is useful.

regards,

--
Joris Gillis (http://www.ticalc.org/cgi-bin/acct-v...i?userid=38041)
Ceterum censeo XML omnibus esse utendum

Joris Gillis wrote:
[big snip of useful, working XSLT]
>
> I hope this is useful.

It's more than useful -- it's superb! Thanks very much. When I figure
out how to combine them into a single step, I'll post the result.

Ed