"invalid XPath expression" error in Visual Studio 2008 TS

Question

I'm learning XSLT via "Beginning XSLT 2.0 From Novice to Professional". Following the source code from the book, I've tried to compile this in Visual Studio 2008 TS:

<xsl:template match="Program">
  <div>
    <p>
      <xsl:if test="@flag">
        <img src="{if (@flag = 'favorite') then 'favorite' else 'interest'}.gif" 
             alt="[{if (@flag = 'favorite') then 'Favorite' else 'Interest'}]" 
             width="20" height="20" />
      </xsl:if>
      <!-- ... -->
    </p>
  </div>
</xsl:template>

The XML data is as follows:

<Channel>
  <Name>BBC1</Name>
  <Program rating="5" flag="favorite">
    <!-- ... -->
  </Program>
  <!-- ... -->
</Channel>

However, when I compile this code I get:

'string(if (@flag = 'favorite') then 'favorite' else 'interest')' 
is an invalid XPath expression.

I've checked the website of the book looking for an errata, unfortunately this hasn't been covered. Any pointers would be fantastic.

Answer 1

Visual studio supports XSLT 1.0. AFAIK no microsoft product supports Xslt 2.0 yet; XQuery 1.0 in SQL Server is the closest you'll get.

Edit: To be clear, the if..then..else syntax is XPath 2.0, not XPath 1.0.

Answer 2

Xslt is much more verbose

you should use somehting like this :

<img>
<xsl:attribute name="src">
<xsl:choose><xsl:when test="@flag='favorite'">favorite</xsl:when><xsl:otherwise>interest</xsl:otherwise></xsl:choose>
</xsl:attribute>
</img>