On 5 January 2015 at 00:49, François Laupretre <franc...@tekwire.net> wrote:
> Hi, > > I know the subject was discussed years ago, and it was decided not to > implement 'friend class' declarations (see > https://bugs.php.net/bug.php?id=34044). > > But the discussions occurred ten years ago, and things (and people) may be > different now. > > Unfortunately, there is no easy-to-use and fast solution for this yet. Most > projects have asked for such a feature for years but, till now, they still > have to rely on a big warning in the documentation. Some, like symfony, > also > add an '@internal' tag in their phpdoc block. This can be checked in an IDE > but that's information, not access restriction. > > IMHO, such a feature would be a valuable addition for PHP 7. If you agree, > I > will write an RFC. > > The feature I was thinking about would be globally similar to C++ friend > classes, except that a PHP friend class would have access to protected > resources, but not private ones (private would remain private). > > The inheritance rules would be similar to C++ rules (adapted from Wikipedia > as it originally includes access to private resources) : > > * Friendships are not symmetric – If class A is a friend of class B, class > B > is not automatically a friend of class A. > > * Friendships are not transitive – If class A is a friend of class B, and > class B is a friend of class C, class A is not automatically a friend of > class C. > > * Friendships are not inherited – A friend of class Base is not > automatically a friend of class Derived and vice versa; equally if Base is > a > friend of another class, Derived is not automatically a friend and vice > versa. > > * Access due to friendship is inherited – A friend of Derived can access > the > protected members of Derived that were inherited from Base (simpler than > the > C++ rule as friend classes and derived classes have the same access > rights). > > Another idea would be to base access restriction on namespaces, but, IMO, > namespaces would not bring the precision we need : each class needs to > define which classes are accepted as 'friends'. > > Please comment. > > Regards, > > François > There is no need for friend classes in order to support this kind of feature (see http://ocramius.github.io/blog/accessing-private-php-class-members-without-reflection/ ) Except for voodoo-cases (AOP frameworks and such) I don't see much of a use-case here. If you need to sync up properties between two classes you can do so by simply using closures, as I described above. Otherwise, making properties `public` and marking them as `@internal DO NOT TOUCH THIS!` is perfectly fine, and doesn't need language-level restrictions IMO. If you need this sort of feature, consider looking at the recently discussed https://github.com/php/php-src/pull/947, which is really much more useful and less magic :-) Greets, Marco Pivetta http://twitter.com/Ocramius http://ocramius.github.com/
