Is it ok for my constructors to destroy the object they are making?

[Crimsonjade]

I still code with PHP 4 standards for compatibility. I have something like:

PHP Code:

class myClass {

    // constructor
    function myClass($some_var)
    {
        // sanity check $some_var
        if ($some_var is NOT sane) {
            $this = null; // destroy the class
            return;
        }

        // do something with $some_var
        ...
    }
} 


I guess the alternative would be no actions in the constructor and then using some function called init() or something. Using an init() seemed like a useless step to me. The way I am doing it I can easily check the variable being assigned the object when I make the class using is_object().

Are there any potential pitfalls of destroying the object inside the constructor?

[ess]

This does not make any sense. The constructor is there to instantiate an instance of a given class. It is not ought to act as a destructor by no means.

I am not sure how you can create a destructor in PHP4, but in PHP5, you can create a destructor by using the following syntax:

PHP Code:

function __destruct() {
// clean references here
} 


[Crimsonjade]

It is not destructing the object. The object was never constructed to begin with. I am not doing anything different than:

PHP Code:

$my_class = New myClass; // no constructor
if ($my_class->init($some_var) != OK) {
    unset($my_class); 
} 


[dumpfi]

Perhaps you should simply use trigger_error() to indicate that there were invalid parameters given to the constructor:

PHP Code:

class myClass {

    // constructor
    function myClass($some_var)
    {
        // sanity check $some_var
        if ($some_var is NOT sane) {
            trigger_error('myClass::myClass : invalid value for `$somevar`, expected: xxx, given: '.((string) $some_var), E_USER_ERROR);
            return;
        }

        // do something with $some_var
        ...
    }
} 


dumpfi

[marek_mar]

The correct way to do this would be to throw an exception in the constructor. This is not possible in PHP4.
You can't assign to $this. AFAIK you have to unset $this and return false (or was it NULL?) for the constructor to fail.

[firepages]

as you are already doing ...
$this=null;return;
is all you need do, but as mentioned I would assume you would require some error reporting & I would have thought that non-construction would normally be fatal ?

[marek_mar]

Assigning to $this is fatal as of PHP 4.1 (or 4.3)...

[Crimsonjade]

as you are already doing ...
$this=null;return;
is all you need do, but as mentioned I would assume you would require some error reporting & I would have thought that non-construction would normally be fatal ?

My plan was the check to see if the variable was indeed an object using is_object. I did not see anything warning me not assign to $this on php.net, but maybe I missed it.

Assigning to $this is fatal as of PHP 4.1 (or 4.3)...

I run php4.4.4 and it works. I see that it does not work in php 5 however. So that is a no go.

Triggering an error really isn't really a route I want to go. I wanted the code to handle the problem, not the user. I guess the init() route it is. No biggie. Thanks for replies.