Ways that PHP4 sucks for work on non-trivial Object-Orientated problems

Ways that PHP 4 sucks for work on non-trivial Object-Orientated problems.

• No support for 'public', 'private', 'protected' data members or functions.
  • Everything is public, so there is no way in PHP 4 to enforce black-box data abstraction.
• Objects are passed as copies by default, not as references by default.
  • In Java, everything is an reference by default (apart from simple data types). This assumption works well when you are working with objects by default.
  • Contrast with PHP, where everything is a copy by default. This assumption works well if you are working with simple data types (Strings, numbers, arrays), where you want to manipulate that data.
  • However, the PHP assumption becomes very annoying when working with objects. This is because with objects, you usually want to modify the original object, not a copy of it.
  • To work around this, you need to use two "