Use dynamic modules to allow correct `call` inheritance

[rewritten]

This should close #19

With this change, the ancestors of a subclass of a service are:

puts my_service_instance.class.ancestors
# SubClass::InjectableCallFacade
# SubClass
# Injectable::InstanceMethods
# SuperClass::InjectableCallFacade
# SuperClass
# Injectable
# Object
# Kernel
# BasicObject

Each concrete class over Injectable gets a dynamically generated module, with a :call implementation that

• if the concrete class is the actual class of an object, takes the arguments as expected, and then call super with no arguments.
• otherwise, it will assume that another facade has already run, so it will just call super with no arguments.

This way we have an alternating chain of methods (one in the facade and one in the concrete class) that call each other.

The dynamically generated module does not need to be assigned to a constant, but it helps when reading traces.

[codeclimate[bot]]

Code Climate has analyzed commit a7ae61e0 and detected 12 issues on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	8
Style	4

View more on Code Climate.