So I'm converting a bunch of OOXML into DITA using XSLT 3 in oXygen with

9.8.0.12 PE.

There's a requirement to use short (4 digit) unique identifiers for the
resuling files and for these to be unique across the content set.  There

many resulting DITA files per source OOXML document.

"A chance to try accumulators!" I thought; I can pre-process the whole

with file numbers in attributes. This isn't an attempt to use streaming;

got a few tens of MB of source.

The accumulator works, BUT the number sequence restarts if I try to use the
accumuator across a sequence of document nodes or a sequence of element

To produce a single continuous sequence of monotonically increasing

with the accumulator, I have to get the whole content set into the same

before creating the numbering attributes.

Is that the expected behaviour?

I get one continous sequence of numbers.

Is there a better way to get the single continuous sequence of numbers?

<xsl:variable as="element(w:document)+" name="numberedSrc">
 <xsl:apply-templates mode="fileNumber" select="$contentSet" />
</xsl:variable>

you would need to use xsl:iterate select="$contentSet" and pass the
latest accumulator on as the parameter of xsl:iterate, like I have done
in https://xsltfiddle.liberty-development.net/bwdwrT

  <xsl:variable name="transformed-docs" as="element(root)*">
      <xsl:iterate select="$docs">
          <xsl:param name="sum" as="xs:integer" select="0"/>
          <xsl:apply-templates>
              <xsl:with-param name="sum" tunnel="yes" select="$sum"/>
          </xsl:apply-templates>
          <xsl:next-iteration>
              <xsl:with-param name="sum" select="$sum +
accumulator-after('acc-example')"/>
          </xsl:next-iteration>
      </xsl:iterate>
  </xsl:variable>

Not sure whether that is anything better, it seems to be a bit too
complicated.