XSLT - Is there a way to append to attributes added with <xsl:attribute>?

Question

Simplified example:

<xsl:template name="helper">
  <xsl:attribute name="myattr">first calculated value</xsl:attribute>
</xsl:template>

<xsl:template match="/>
  <myelem>
    <xsl:call-template name="helper" />
    <xsl:attribute name="myattr">second calculated value</xsl:attribute>
  </myelem>
</xsl:template>

Is there some way for the second to append the second calculated value to the same myattr attribute in the result node?

I've seen it is possible to use an attribute value template if the target attribute is in the source xml, but can I reference somehow the value of the attribute I have earlier appended to the result node?

Thanks in advance!

Answer 1

One approach you could take is add a parameter to your helper template, which you append to the attribute value.

<xsl:template name="helper">
  <xsl:param name="extra" />
  <xsl:attribute name="myattr">first calculated value<xsl:value-of select="$extra" /></xsl:attribute>
</xsl:template>

Then you can just past in your second calculate value as the parameter

<xsl:template match="/>
  <myelem>
    <xsl:call-template name="helper">
      <xsl:with-param name="extra">second calculated value</xsl:with-param>
    </xsl:call-template>
  </myelem>
</xsl:template>

You don't have to set the param with each call though. If you don't want anything appended, just called the helper template with no parameter, and won't append anything to the first calculated value.

Answer 2

The simplest approach would be to change the nesting a bit - have the helper just generate text nodes and put the <xsl:attribute> in the calling template:

<xsl:template name="helper">
  <xsl:text>first calculated value</xsl:text>
</xsl:template>

<xsl:template match="/>
  <myelem>
    <xsl:attribute name="myattr">
      <xsl:call-template name="helper" />
      <xsl:text>second calculated value</xsl:text>
    </xsl:attribute>
  </myelem>
</xsl:template>

This will set myattr to "first calculated valuesecond calculated value" - if you want a space between "value" and "second" you must include that inside one of the <xsl:text> elements

      <xsl:text> second calculated value</xsl:text>