Python Essential Reference, Second Edition

Defining New Types

New types of objects can also be defined in extension modules. However, this process is considerably more advanced than simply accessing a few C functions. Because of this complexity, you should consider implementing a new type only in the following situations:

• The type is not easily constructed from existing Python types.

• The type requires interaction with the operating system or another special feature not provided by the interpreter or the standard library.

• The type hasn’t already been implemented elsewhere. For example, efficient matrix types have already been implemented, so it would make little sense to reinvent them. It’s always a good idea to check the Python libraries and newsgroups before implementing a new type. The ...