<?php
class TheObj {
        public $RealVar1, $RealVar2, $RealVar3, $RealVar4;
        public $Var = array();

        function __set($var, $val) {
            $this->Var[$var] = $val;
        }
        function __get($var) {
            if(isset($this->Var[$var])) return $this->Var[$var];
            else return -1;
        }
        function __unset($var) {
            unset($this->Var[$var]);
        }
    }

    $SomeObj = new TheObj;

    // this will fine
    $SomeObj->RealVar1 = 'somevalue';
    $SomeObj->{'RealVar2'} = 'othervalue';
    $SomeObj->{'RealVar'.(3)} = 'othervaluetoo';
    $SomeObj->{'RealVar'.'4'} = 'anothervalue';

    // this will fine too
    $SomeObj->Virtual1 = 'somevalue';
    $SomeObj->{'Virtual2'} = 'othervalue';

    // it's can't be used since this will encounter error
    $SomeObj->{'Virtual'.(3)} = 'othervaluetoo';
    $SomeObj->{'Virtual'.'4'} = 'anothervalue';

    // but this will fine, ofcourse
    $SomeObj->Var['Virtual'.(3)] = 'othervaluetoo';
    $SomeObj->Var['Virtual'.'4'] = 'anothervalue';


    var_dump($SomeObj->RealVar1);
    print $SomeObj->{'RealVar'.(3)}."\n";

    unset($SomeObj->RealVar1);
    unset($SomeObj->{'RealVar'.(3)});

    //the lines below will catch by '__get' magic method since these variables are unavailable anymore
    var_dump($SomeObj->RealVar1);
    print $SomeObj->{'RealVar'.(3)}."\n";

    // now we will try to unset these variables
    unset($SomeObj->Virtual1);
    unset($SomeObj->{'Virtual'.(3)});

    //but, these variables are still available??? even though they're "unset"-ed
    print $SomeObj->Virtual1."\n";
    print $SomeObj->{'Virtual'.(3)}."\n";
?>