Abstract Interfaces

An abstract interface for a procedure which will act on each item in a list.

Performs an addition operation on two container objects, returning the result in a container.

An abstract interface for a procedure comparing two container objects. Note that a procedure may satisfy both this abstract interface and subtraction_func.

An abstract interface for a procedure finding the difference between two items, item1 - item2. Note that a procedure may satisfy both this abstract interface and comparison_func.

An abstract interface for a function which tests a container object in some way