"Martin Honnen" <mahotrash@y...> wrote in message 
news:#CtxM8hlHHA.4772@T......
> Edward Wohlman wrote:
>> Is it possible to use xsl to perform a topological sort such that data 
>> such as
>>
>>     <Route>
>>         <Place>B</Place>
>>         <Place>D</Place>
>>         <Place>F</Place>
>>     </Route>
>>     <Route>
>>         <Place>A</Place>
>>         <Place>B</Place>
>>         <Place>C</Place>
>>         <Place>E</Place>
>>     </Route>
>>     <Route>
>>         <Place>C</Place>
>>         <Place>D</Place>
>>         <Place>E</Place>
>>     </Route>
>>     <Route>
>>         <Place>A</Place>
>>         <Place>E</Place>
>>         <Place>F</Place>
>>     </Route>
>>
>> can be transformed to
>>
>>    <Route>
>>        <Place>A</Place>
>>        <Place>B</Place>
>>        <Place>C</Place>
>>        <Place>D</Place>
>>        <Place>E</Place>
>>        <Place>F</Place>
>>    </Route>
>
> The simply looks like an alphabetical sort of distinct Place contents, 
> like this:
>
> <xsl:stylesheet
>   xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>   version="1.0">
>
> <xsl:strip-space elements="*"/>
>
> <xsl:output method="xml" indent="yes"/>
>
> <xsl:key name="distinct-place" match="Place" use="."/>
>
> <xsl:template match="/*">
>   <xsl:copy>
>     <Route>
>       <xsl:apply-templates select="Route/Place[generate-id() = 
> generate-id(key('distinct-place', .)[1])]">
>         <xsl:sort select="." data-type="text"/>
>       </xsl:apply-templates>
>     </Route>
>   </xsl:copy>
> </xsl:template>
>
> <xsl:template match="Place">
>   <xsl:copy>
>     <xsl:apply-templates/>
>   </xsl:copy>
> </xsl:template>
>
> </xsl:stylesheet>
>
>
> -- 
>
> Martin Honnen --- MVP XML
> http://JavaScript.FAQTs.com/

Thanks, but I was using A-B-C as a simplified example of what I need.
The actual data I will be operating on will not be sort able so easily.

I've made a bit of a start at working out the dependencies for each place

<xsl:transform version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
xmlns:msxsl="urn:schemas-microsoft-com:xslt">
	<xsl:key name="places" match="//Route/Place" use="."/>
	<xsl:template match="TopoTest">
		<table border="2">
		<tr><th>place</th><th>depends on</th></tr>
		<xsl:for-each select="Route/Place[generate-id() = 
generate-id(key('places',.)[1])]">
			<tr>
			    <td><xsl:value-of select="."/></td>
			    <td>
				<xsl:for-each select="key('places',.)">
					<xsl:for-each select="preceding-sibling::node()">
						<xsl:value-of select="."/>
					</xsl:for-each>
				</xsl:for-each>
			    </td>
			</tr>
		</xsl:for-each>
		</table>
	</xsl:template>
</xsl:transform>

but even that is not giving me quite what I wanted quite yet.

Looks like I need to learn a lot more about this stuff