/**
* Short description of method build
*
* @access public
* @author Joel Bout, <*****@*****.**>
* @param SimpleXMLElement data
* @return oat\taoQtiItem\model\qti\expression\Expression
*/
public static function build(SimpleXMLElement $data)
{
$returnValue = null;
$expression = null;
$expressionName = $data->getName();
//retrieve the expression attributes
$attributes = array();
foreach ($data->attributes() as $key => $value) {
$attributes[$key] = (string) $value;
}
// Create expression function of its type (If specialization has been done for the expression type)
$expressionClass = 'oat\\taoQtiItem\\model\\qti\\expression\\' . ucfirst($expressionName);
if (class_exists($expressionClass)) {
$expression = new $expressionClass($expressionName, $attributes);
} else {
$expression = new CommonExpression($expressionName, $attributes);
}
// If the expression has a value
$expressionValue = (string) trim($data);
if ($expressionValue != '') {
$expression->setValue($expressionValue);
}
// All sub-expressions of an expression are embedded by this expression
$subExpressions = array();
foreach ($data->children() as $subExpressionNode) {
$subExpressions[] = self::build($subExpressionNode);
}
$expression->setSubExpressions($subExpressions);
$returnValue = $expression;
return $returnValue;
}
/**
* Short description of method getCompositionRules
*
* @access public
* @author Joel Bout, <*****@*****.**>
* @return array
*/
public function getCompositionRules()
{
$subExpressions = array();
foreach ($this->components as $irp) {
$subExpressions[] = new CommonExpression('variable', array('identifier' => $irp->getOutcome()->getIdentifier()));
}
$sum = new CommonExpression('sum', array());
$sum->setSubExpressions($subExpressions);
$summationRule = new SetOutcomeVariable($this->outcomeIdentifier, $sum);
$returnValue = array($summationRule);
return (array) $returnValue;
}