That is the hope. However, we are being circular in some cases. Its pretty easy to visualise an active machine which is the handler, and the rules by which that machine operates, and the definition of the template of the actual physical things that the machine eats. Handler term may have come from Axis project. Each handler does piece of work that handles one or more blocks.
Module can have more than one handler.
Handler can be used by more than one module. For the purpose of this definition, what we have is close enough. Perhaps do so with some of our scenarios. The parts that handle each may need to interact. Keep eye on fact that some things aren't processed but the information is there if necessary anywhere in the chain.