Martin wrote:

Doesn't
   <xsl:value-of select="$headers" separator="{$field-separator}"/>
suffice to get what you want?

That is fantastic - thanks Martin!

However, .......

That solves the problem of showing the headers, but I also need to loop over
some values, compute an appropriate value to output, and then follow the value
with a tab (hex 9). Like this:

<xsl:for-each select="foo">
	<xsl:variable name="value" select="f:compute-value(.)"/>
	<xsl:sequence select="$value" />
	<xsl:sequence select="$field-separator"/>
</xsl:for-each>

So I really need a general solution.

How can I output a tab (hex 9) without also getting the space (hex 20)
characters surrounding the tab character?

/Roger