RE: [xsl] Recursive counting

["Michael Kay" <mike@xxxxxxxxxxxx>]

> Well after success with my first recursive template I was all 
> set to make one of my own, but now shamefully am coming to 
> the list for advice over something that appears quite simple.

First thing is to recognize this as a grouping problem. For each distinct
value of @type you need to do something.

In XSLT 2.0:

<xsl:for-each-group select="/*/options/o" group-by="@type">
  <xsl:sort select="current-grouping-key()"/>
  <out type="{current-grouping-key()}"
       count="{count(/*/person[@pref=current-group()]}"/>
</xsl:for-each-group>

> 
> XML ------->
> 
> <options>
>    <o type="A">who</o>
>    <o type="A">what</o>
>    <o type="A">when</o>
>    <o type="B">how</o>
>    <o type="B">nexus</o>
>    <o type="B">triumph</o>
>    <o type="C">alligator</o>
>    <o type="C">spurn</o>
> </option>
> 
> <people>
>   <person pref="who" />
>   <person pref="nexus" />
>   <person pref="how" />
>   <person pref="alligator" />
>   <person pref="spurn" />
>   <person pref="triumph" />
>      .... etc ....
> </people>
> 
> 
> Desired output ------->
> 
> <!-- @count corresponds to number of times  the preference 
> appeared among the list of <people> --->
> 
>   <out type="A" count="1" />
>   <out type="B" count="3" />
>   <out type="C" count="1" />
> 
> 
> Stipulation: --------->
> 
> <out>'s must be sorted alphabetically, regardless of <option> order.