note 119485 added to language.oop5.visibility

After having the how explained, many people will still be left wondering about the why. How should the different kinds of visibility be used in practice? Some kind of labelling for the public and private parts of an interface is certainly necessary. We need to be clear which methods will be part of the public interface and which are only used internally . In older versions of php notionally-private functions were prefixed with an underscore - a much simpler and more elegant solution to the labelling problem. "Protected" adds clutter which affects readability. It adds a lot of unnecessary typing to what is already a keyboard-intensive job. As for enforcement.. no-one ever got mixed up about public/private so long as they were clearly labelled. As such, "protected" is an attempt to solve a problem which simply did not exist. Private is even worse. It specifically encourages bad object-oriented code with the use of inheritance in places where you should be thinking about separate, co-operating objects. A feeling that classes which inherit from each other need to hide some of their bits from each other is a sure sign that you need to break the code up into separate objects. This is exactly what encapsulation is for. It doesn't make any sense to try to encapsulate bits inside an inheritance tree. Classes which extend other classes must always be free to override whatever it is they need to override in their parent classes. In short, use protected if you must, do not use private at all. Do not try to squeeze too much new functionality into an inheritance tree: create networks of co-operating objects with clearly-defined responsibilities instead. It's a real shame that php took the decision to implement private and protected. They add nothing to our ability to write good quality OO code; they simply make that code more difficult to write and to understand. Clarity and simplicity are incredibly important in programming but now both php programmers and php developers are stuck with these unnecessary layers of complexity. ---- Server IP: 72.52.91.14 Probable Submitter: 212.159.44.241 ---- Manual Page -- http://php.net/manual/en/language.oop5.visibility.php Edit -- https://master.php.net/note/edit/119485 Del: integrated -- https://master.php.net/note/delete/119485/integrated Del: useless -- https://master.php.net/note/delete/119485/useless Del: bad code -- https://master.php.net/note/delete/119485/bad+code Del: spam -- https://master.php.net/note/delete/119485/spam Del: non-english -- https://master.php.net/note/delete/119485/non-english Del: in docs -- https://master.php.net/note/delete/119485/in+docs Del: other reasons-- https://master.php.net/note/delete/119485 Reject -- https://master.php.net/note/reject/119485 Search -- https://master.php.net/manage/user-notes.php