code: public void setSelect(XPath v)
    {
  
      if (v.getPatternString().indexOf("{") < 0)
        m_selectExpression = v;
      else
        error(XSLTErrorResources.ER_NO_CURLYBRACE, null);
    }
docs: Set the "select" attribute.
  xsl:sort has a select attribute whose value is an expression.
  For each node to be processed, the expression is evaluated
  with that node as the current node and with the complete
  list of nodes being processed in unsorted order as the current
  node list. The resulting object is converted to a string as if
  by a call to the string function; this string is used as the
  sort key for that node. The default value of the select attribute
  is ., which will cause the string-value of the current node to
  be used as the sort key.
  
  @param v Value to set for the "select" attribute