static Methods: different behavior

[arnoschaefer]

Hi,

 

I have this bit of code:

 

class bla {

    static public function foo () {

    }

}

 

$classname = "bla";

$classname::foo ();

 

in my installation of PHP 5.2.4RC1 (OpenSuSE 10.2), this works fine. On another server with PHP 5.2.2, this results in

 

Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM in /www/htdocs/w0088307/blog/version/test/tt2.php on line 9

 

(PAAMAYIM_NEKUDOTAYIM appears to mean double colon ().

 

Can anyone tell me if this is a change between version 5.2.2 and 5.2.4 (I did not find anything in the ChangeLog), or if this is a configuration problem? Is the above code legal at all?

 

Best Regards,

 

Arno

 

 

[lemmin]

try $classname->foo();

[trq]

Looks legal to me, I use this type of stuff quite a bit without issue. I can't say Ive tried with static methods though.

 

Changes between 5.2.2 and 5.2.4 should merely be bug fixes, not feature changes. I'm sorry, but I can't think of any config option that may cause this either.

[arnoschaefer]

> try $classname->foo();

 

$classname is not an object, but a string:

 

Fatal error: Call to a member function foo() on a non-object in /www/htdocs/w0088307/blog/version/test/tt2.php on line 9

 

[lemmin]

Oh, sorry, I didn't pay attention to what you were trying to do. What about bla::foo(); I think that is what you are looking for.

[trq]

Try...

 

${classname}::foo ();

[lemmin]

Oh, are you trying to use variable variables? If so, this should work: $$classname::foo();

[trq]

Oh, are you trying to use variable variables? If so, this should work: $$classname::foo();

 

No. Just trying to use a variable's value as an object reference. It should be legal.

[arnoschaefer]

> What about bla::foo(); I think that is what you are looking for.

 

Well, the whole point of using a variable $classname is that I don't know which class I will be using in advance. Otherwise I would obviously use the classname directly as you suggest. But thanks anyway.

 

[arnoschaefer]

> Try...

>

> Code:

>

> ${classname}::foo ();

 

Does not work either. Still the same error message.

 

[trq]

I'm at home now using 5.2.2 I get the same error as you. It must be a caveat with static methods. This....

 

<?php

class bla {
    public function foo () {
        echo "foo!";
    }
}

$class = 'bla';
$obj = new $class;
$obj->foo ();

?>

 

works as expected, but obviously its not what you want. Sorry, but I can't seem to help.

[lemmin]

Though I can't seem to find it on their website, I found something that claimed this to be part of the changelog: "Added possibility to call static class members using variables."

 

It would seem you can't do it in previous version.

[arnoschaefer]

> $class = 'bla';

> $obj = new $class;

> $obj->foo ();

 

Yes, that was what I used as a workaround so far, but I just found a hint in the PHP doc on the "scope resolution operator" (double colon) and they had another workaround that is somewhat more elegant and does not require instantiating an object:

 

eval ("$classname::foo ();");

 

or, with an additional parameter and return value:

 

eval ("\$result = $classname::foo (\$parameter);");

 

(note the escaped $ signs).

 

There was a discussion that $class::foo() does not work, but why it suddenly started working in version 5.2.4 is still an interesting question. Maybe it was regarded as a bug fix. Unfortunately, there does not seem to be a change log yet for the 5.2.4 release candidates.

 

Thanks anyway for your help and effort.

 

[arnoschaefer]

Though I can't seem to find it on their website, I found something that claimed this to be part of the changelog: "Added possibility to call static class members using variables."

 

It would seem you can't do it in previous version.

 

Yes, that's most likely it. Thanks a lot for the info.