Loading multiple versions of the same class

Question

Let\'s say I release a code library as a standalone PHP class. Someone then uses version 1.0 of that library in their application. Later, I release version 2.0 of the libr

Answer 1

I decided on a slightly alternate route. The namespace method works, but you need a different namespace for each version of the class. So it's not really scalable, because you have to pre-define the number of available namespaces.

Instead, I've settled on a specific naming schema for the classes and a version loader/instantiater.

Each class will take the following format:

The parent My_Library class will actually end up containing a few identifiers specific to the library - purpose, compatibility statements, etc. That way I can perform other logical checks to make sure the right My_Library exists before moving forward and claiming that My_Library_1_0 is really version 1.0 of the library I want.

Next, I have a loader class that I'll be using in my main project:

Once this is done, you can use Loader to load both instances of the class or simple references if you want to use static methods:

$reference = Loader::load( 'library.php', 'My_Library', '1.0' );

$loader = new Loader();
$instance = $loader->load( 'library.php', 'My_Library', '1.0' );

Not quite the same as the namespace version I was shooting for, but it works and alleviates my concerns about breaking things for the end user. I am assuming that two different versions of My_Library_1_0 would be the same, though ... so there's still a dependence on third party developers knowing what they're doing.