Ruby namespace flattening gotchas?

I must use a ruby library that looks like it was written by a java developer because the namespaces are so looooooonngg. And I have to use a lot of the classes in the namespaces.

I would like to make my own namespace wrapper/alias. I tried this in irb and it seems to work. My question is if this is the "correct" way to do it (eg include vs extend) and/or what gotchas I have to watch out for besides class name collisions

module System

   include ::Com::Company::Project::Core::System::Core   # About 5 classes
   include ::Com::Company::Project::Core::System::Common # About 15 classes

   module SubSystem
     include ::Com::Company::Project::Core::SystemSubSystem::Core   # About 10 classes
     include ::Com::Company::Project::Core::SystemSubSystem::Common # About 15 classes
   end
end


....
facade = System::Facade.new( System::SubSystem.new(...) )

Solution

If you want to shorten the namespace, you could introduce a constant which refers to a module deep within the hierarchy, e.g.:

module System
  LibCore = ::Com::Company::Project::Core

  include LibCore::System::Core
  include LibCore::System::Common

  module SubSystem
    include LibCore::SystemSubSystem::Core
    include LibCore::SystemSubSystem::Common
  end
end

Another variant, although quite uncommon, is to define your top-level module from within the library's namespace via ::, e.g.:

module Com::Company::Project::Core
  module ::System # <- using :: defines System on the top level
    include System::Core
    include System::Common

    module SubSystem
      include SystemSubSystem::Core
      include SystemSubSystem::Common
    end
  end
end

Or maybe even:

module Com::Company::Project::Core::System
  module ::System
    include Core
    include Common
  end
end

module Com::Company::Project::Core::SystemSubSystem
  module ::System::SubSystem
    include Core
    include Common
  end
end

All variants above will result in:

System.included_modules
#=> [Com::Company::Project::Core::System::Common,
#    Com::Company::Project::Core::System::Core]
System::SubSystem.included_modules
#=> [Com::Company::Project::Core::SystemSubSystem::Common,
#    Com::Company::Project::Core::SystemSubSystem::Core]