[RESOLVED] Using eval and objects

Shawazi

$s = "\$currentClass = new " . $this->class_name."();"; 
echo "$s<br />";
eval($s) or die("Can't create \$currentClass");

This prints out:

$currentClass = new creative();
Can't create $currentClass. The actual fatal error is:

Catchable fatal error: Object of class creative could not be converted to string in...

paulnaj

Hi,

Doesn't eval() always return NULL anyway (unless you actually return something from the argument) so your 'OR' statement will always print 'Can't create $currentClass', even if the instance is created.

Whatever, try using single-quotes to make life easier ... the only thing you then need to escape is the single-quote itself ...

$s = '$currentClass = new ' . $this->class_name.'();';
echo $s.'<br />';
eval($s); // Always returns NULL so don't use value to see if $s is valid.
echo '<pre>'; var_dump($currentClass); echo '</pre>';

If you are getting errors, then they may be to do with the class itself.

NogDog

No need for an eval() that I can see.

$class = get_class($this);
$currentClass = new $class;

mpb001

"If eval() is the answer, you're almost certainly asking the
wrong question." -- Rasmus Lerdorf, BDFL of PHP

http://uk3.php.net/manual/en/function.eval.php

$currentClass = new $this->class_name();

PHP has lots of ways to get around eval..
The () act as a trigger to call/create something something.

class test
{
    function a()
    {
        echo "a<br/>";
    }


function b()
{
    echo "b<br/>";
}
}

$test = "test";
$a = new $test();
$a->a();


$test2 = "b";
$a->$test2();

//Can use call_user_func http://uk3.php.net/manual/en/function.call-user-func.php instead for the dynamic method call.

Shawazi

I'm now using

$refObjArrayIndexObj = new $this->class_name(); 
call_user_func(array($this->class_name, $this->method_name), $this_db_row_id);

However I get this error:

Fatal error: Using $this when not in object context in....

The class being called is:

class creative extends GenericObject {
	public function getWatchedInfo($this_id="") {

	$this->Initialize("val1", $this_id);
}

}

mpb001

Looks like you are using $this-> outside of a class.

probably this line is calling it statically.

call_user_func(array($this->class_name, $this->method_name), $this_db_row_id);

instead of

call_user_func(array($refObjArrayIndexObj, $this->method_name), $this_db_row_id);

Uses the $refObjArrayIndexObj instantiated object

http://uk3.php.net/manual/en/function.call-user-func.php#20574

Might need an & in 4 like the example above.

Shawazi

Ah yeah doing that fixed it totally.