Re: XSLT 1 and grouping numbers by if the following n

(using XSLT 1)
Hi,

I would like to group numbers by if the following number is current number + 1 and so on.

Example:

<a>1</a>
<a>3</a>
<a>4</a>
<a>5</a>
<a>7</a>
<a>9</a>
<a>10</a>

<group><a>1</a></group>
<group><a>3 <a>4</a> <a>5</a></group>
<group><a>7</a></group>
<group><a>9</a> <a>10</a></group>

Any insight will be appreciated.

<x>
<a>1</a>
<a>3</a>
<a>4</a>
<a>5</a>
<a>7</a>
<a>9</a>
<a>10</a>
</x>

<xsl:output indent="yes"/>
<xsl:template match="x">
<xsl:for-each-group group-starting-with="a[
not(preceding-sibling::a) or
not(number(.)=1+preceding-sibling::a[1])]" select="a">
<group>
<xsl:copy-of select="current-group()"/>
</group>
</xsl:for-each-group>
</xsl:template>

$ saxon9 numg.xml numg.xsl
<?xml version="1.0" encoding="UTF-8"?>
<group>
   <a>1</a>
</group>
<group>
   <a>3</a>
   <a>4</a>
   <a>5</a>
</group>
<group>
   <a>7</a>
</group>
<group>
   <a>9</a>
   <a>10</a>
</group>