Question

I’ve just started getting familiarized with OO features of PHP, and I would like to ask you something about the $this variable. First of all, if a class that I’m using the $this keyword in does not have a defined property variable foo, does that mean that using the following code:

$this->foo = 5;
echo $this->foo;

will create the foo property on the object on runtime, like in JavaScript? What is the visibility of this property?

Answer 1

Yes, this will create the foo property, and its visibility will be public (which is the default).

You could test this quite easily:

<?php
class Foo {
    public function setFoo($foo) {
        $this->foo = $foo;
    }
}

$f = new Foo();
$f->setFoo(5);
echo $f->foo;

Will print 5 with no errors.