Why can't I do math in a class property declaration? [closed]

Answer 1

Adding a default value for a property should be done inside the constructor. To add default values when declaring the property is just a non-OO thing that rolls in PHP to make live for developers easier, but -- as you can see -- it isn't supported very well yet.

The solution:

class Foo
{
    private $var;

    public function __construct()
    {
        $this->var = 2 + 3
    }
}