Ex-2.76

I'm going to present views on all three strategies with respect to adding new data type and operations.

Explicit dispatch programming:
Adding new Data Type:
We must put appropriate code to support new data type in *all* generic operation definitions and write constructor for it.
Adding new Operation:
Implement it for all data types and We must create a generic operation for it that does type dispatch on all the data types.

Data directed programming:
Adding new Data Type:
No change to generic operation, but need to put all the operations for this data type into operation-type table.
Adding new Operation:
Put the new operation definitions for all data types into operation-type table and Need to create a generic operation which is very simple in this case, that will just do a get on the table to find appropriate procedure.

Message passing style programming:
Adding new Data Type:
We just need to create a new constructor for it(that returns dispatch procedure).
Adding new Operation:
We have to modify all the constructors to include this new operations.

Most appropriate organization for frequent addition of new data types would be the message passing style and same for frequent addition of operations would be data directed programming.