A Registry that keeps our Operation instances.
Node doesn't contain an operation instance
even if it has an operation type otherwise it would
waste the memory resources.
The node contains only operation Symbol, and the registry
based on it provides the relative operation instance
A Registry that keeps our Operation instances. Node doesn't contain an operation instance even if it has an operation type otherwise it would waste the memory resources. The node contains only operation Symbol, and the registry based on it provides the relative operation instance