The logic is basically:

allocate a grouping key which is effectively:

* for figure elements, a unique key

* for everything else, the local name of the element

then put adjacent elements with the same grouping key into the same group.

Perhaps it would be clearer to write

group-adjacent="if (self::figure) then generate-id() else local-name()"

-- the effect would be the same.

Michael Kay
Saxonica

> On 28 Mar 2018, at 17:14, Rick Quatro rick@xxxxxxxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> My general intent is to group on figure elements. All consecutive siblings
> that aren't <figure>s (<para> or otherwise) should be in their own group.
>
> Michael's solution works, but I am having trouble getting my head around
the
> logic. Thank you Martin and Michael for the quick replies.
>
> Rick
>
>
>
> -----Original Message-----
> From: Martin Honnen martin.honnen@xxxxxx
> <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>
> Sent: Wednesday, March 28, 2018 12:01 PM
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: Re:  for-each-group
>
> On 28.03.2018 17:53, Rick Quatro rick@xxxxxxxxxxxxxx wrote:
>
>> I have a <step> element that looks something like this:
>>
>> <steps>
>>
>>   <step>
>>
>>     <para>Intro stuff</para>
>>
>>     <para>More intro stuff</para>
>>
>>     <figure/>
>>
>>     <figure/>
>>
>>     <para>Conclusion stuff</para>
>>
>>     <para>More conclusion stuff</para>
>>
>>   </step>
>>
>> </steps>
>>
>> I want 4 separate groups:
>>
>> 1) First two <para> elements.
>>
>> 2) First <figure>
>>
>> 3) Second <figure>
>>
>> 4) Last two <para> elements.
>
> Can you explain the rules for that result, do you want to group any
adjacent
> "para" element into one group but keep each "figure" element in its own
> group?
>
> In that case you can use
>
>   <xsl:for-each-group select="*" group-adjacent="boolean(self::para)">
>     <xsl:choose>
>        <xsl:when test="current-grouping-key()">
>          <group>
>             <xsl:apply-templates select="current-group()"/>
>          </group>
>       </xsl:when>
>       <xsl:otherwise>
>         <xsl:for-each select="current-group()">
>            <group>
>               <xsl:apply-templates select="."/>
>            </group>
>         </xsl:for-each>
>       </xsl:otherwise>
>    </xsl:choose>
>   </xsl:for-each-group>