Also, what is the recommended way to define an empty string-valued
  variable?

  <xsl:variable name="foo"/>
  <xsl:variable name="foo" select="''"/>
  <!-- or something else? -->

They are equivalent, XSLT spec special cases the situation of no select
attribute and no content and says it makes an emty string (rather than
an empty rtf)

> What is the recommended way to define a string-valued variable computed
> by a conditional instruction?  Here's an example from a stylesheet I'm
> working on:

without doing some very hairy Xpath to move the condition into the
select expression you pretty much have to use xsl:choose (xsl 2 of
course you could use Xpath2 if () then ... else .. inside a select
expression)

on the face of it if you often use the variable it would be worth
forcing a one-off coersion to string so

<xsl:variable name="temp">
 <xsl:choose>
...
</xsl:variable>
<xsl:variable name="source" select="string($temp)"/>

However if I suggest that, Mike is bound to say that saxon can spot if an
RTF variable is always used as a string and so optimises away its
internal node structure. so doing this explictly makes no difference.


David

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