public function process()
    {
        $expr = $this->getExpression();
        $state = $this->getState();

        $var = $state->getVariable($expr->getIdentifier());

        return ($var === null) ? null : $var->getDefaultValue();
    }
public function process()
    {
        $expr = $this->getExpression();
        $state = $this->getState();

        $var = $state->getVariable($expr->getIdentifier());

        return ($var === null) ? null : $var->getDefaultValue();
    }
public function process ( ) { $ expr = $ this -> getExpression ( ) ; $ state = $ this -> getState ( ) ; $ var = $ state -> getVariable ( $ expr -> getIdentifier ( ) ) ; return ( $ var === null ) ? null : $ var -> getDefaultValue ( ) ; }
Returns the defaultValue of the current Expression to be processed. If no Variable
with the given identifier is found, null is returned. If the Variable has no defaultValue,
null is returned.

@return mixed A QTI Runtime compliant value.
Returns the defaultValue of the current Expression to be processed . If no Variable with the given identifier is found null is returned . If the Variable has no defaultValue null is returned .