UPDATE: This language feature is called duck typing and it is already available for python or javascript. I really want it for php.

php-duck-typing

I am looking for a possibility to check, if an object fit to an interface, which is not implemented by the object.

I also asked the question at https://stackoverflow.com/questions/47533037/check-an-object-for-interface-which-is-not-impemented

Example

You include PackageA to your project. This package is not yours.

In your own PackageB you have a Service which expects an interface you write yourself. And you also have a TestUser which fits to the UserInterface.

Now the user object of PackageA fits to the UserInterface, but you can not add this user object to the service method by typehinting the interface.

possible solutions?

With the example/index.php the current code solutions will be shown.

1. check the fitting by reflections

One solution can be -> delete the typehint and check it yourself like the CompareService.

2. create a pull request to PackageA and add an interface there

Normally there should be a interface, but it could be a solution to add the interface to the possible external package.

3. use the decorator pattern

An other way could be to use the decorator pattern. So the user object of PackageA will be given to an object of PackageB which implements the UserInterface.

4. ???

Is there any other, probably better solution? Or is there a plan for future php version to support something like that?