Access class instance from function

Question

Is it possible to do something similar to this:

class Class1
{
    public function __construct($param1) {
        # code ...
    }

    public function method1() {
        # code ...
        echo 'works';
    }
}

$class1 = new Class1('foo');

function function1() {
    $class1->method1();
}

function1();

Or do I need to pass the instance of the class to the function ?

Thank you.

Nope Don't do it.do this instead function function1() { $class1 = new Class1('foo'); $class1->method1(); } — Ankur
– Ankur, Commented Jan 17, 2015 at 16:21
@Shan The reason I don't do this is that the parameter I send to the class (a config array in this case) is not accessible from the function. — tleb
– tleb, Commented Jan 17, 2015 at 16:22

Jacek Kowalewski · Accepted Answer · 2015-01-17 16:22:22Z

1

You must pass the instance to the function, or use GLOBALS :).

1) Instance - best solution

function function1(Class1 $class) {
    $class->method1();
}

2) Globals - http://php.net/manual/en/reserved.variables.globals.php - But You must be careful, Globals, are very hard to follow and test your code. Best method is just to pass it as argument.

function function1() {
    global $class1;
    $class1->method1();
}

PS. You should try to avoid mixing object - function programming. If You decide to use object programming, try to implement everything as an object. It is easier to maintance, read and update. Mixing objects and function is good, only if You are 'rewriting' old system to object, and not everything can be done at once.

PS2. Objects should always implement real objects, or abstraction objects (router, database, table, user). In that case, when Your function needs object, passing it as a paremeter is what You need - in reality this function need this object. So there is no shame in passing it, rather proudness ;).

Best regards, hope it helps.

edited Jan 17, 2015 at 16:22

answered Jan 17, 2015 at 16:17

Jacek Kowalewski

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3 Comments

tleb Over a year ago

Thank you, it's what I thaught.

Jacek Kowalewski Over a year ago

No problem. It is a good habit, to always pass variables / attributes / objects as a function arguments. It makes the code, clear, dependencies are clear, and it is very easy to test the code on each level.

tleb Over a year ago

In my actual project, I only have 4 functions, which are quite small, but not linked in any way (add_log, add_zero, connection_db and format_exception), and I don't believe it makes it easier to put them all in one class and make them static.

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