Class CountDict

source code

object --+    
         |    
   Counter --+
             |
            CountDict

A counter class for memoized values stored in a dictionary, with keys based on the method's input arguments.

A CountDict object is instantiated in a class for each of the class's methods that memoizes its return value in a dictionary, indexed by some key that can be computed from one or more of its input arguments.

We expect that the metaclass initialization will fill in the .underlying_method attribute with the method that we're wrapping. We then call the underlying_method method after counting whether the computed key value is already present in the memoization dictionary (a hit) or not (a miss).