Metatools 0.1.1

Python Metaclass Construction Tools

This package contains the metatools module, which provides a utility class (MetaClass) which metaclasses can extend. It provides three static methods (available only on classes inheriting from MetaClass; they will not clutter up your actual classes) which can be used to enhance inheritance.

The most important of these static methods is the iter_bases() method. When passed a list of base classes, such as those passed to the __new__() method, it generates a list of the superclasses in proper Python Method Resolution Order. This can be used with the inherit_dict() and inherit_set() static methods.

Both inherit_dict() and inherit_set() have similar interfaces. When passed a base class, the dictionary for the class being constructed, and the name of an attribute containing the dictionary or set which should have inheritance rules applied, they look up the attribute in both the base class and in the namespace dictionary, then walk through all entries in the base class’s version; if the entry does not currently exist in the namespace’s version of that dictionary or set, then it is automatically added. Both routines return a list of items added, if the metaclass needs to perform any additional post-processing on the entries. The items may also be filtered by passing a callable returning True or False as the inherit parameter to the routines. Additionally, if inherit is False or None (or any other value that tests as False), then the items are not automatically added to the dictionary or set, but are still provided in the list of returned items.