title: XSLT variable into the curly braces
body: <p>What is the meaning of curled brackets {} in the following sample
  (in preceding lines, the variable $fieldName is initialized and populated with string):  </p>
  
  <pre><code>&lt;xsl:element name="{$fieldName}"&gt;
      &lt;xsl:apply-templates select="field"/&gt;
  &lt;/xsl:element&gt;
  </code></pre>