Py_Dynamic_module_creation

Python has great metaprogramming capabilities.

Python modules are implicitly created with a file.  It is one of the primary
namespacing mechanisms in Python.  Occasionally you may wan to dynamically
create one. 

There are a few use cases for dynamic module creation.  The use case that
comes up most frequently is modules created in the service of automated tests.
Sometimes a module is needed as input and sometimes it's needed as a mock.
Other use cases exist, but are more rare in my experience.  One I have done
recently is automatic module creation to create the appropriate modules a
framework or library expects. There have been other instances as well,
although infrequent.  Regardless, it's a useful tool to have in your toolbox
should the need ever arise.


    from types import ModuleType
    import sys

    def make_module(new_module, doc="", scope=locals()):
        """
        make_module('a.b.c.d', doc="", scope=locals()]) -> 

        * creates module (and submodules as needed)
        * adds module (and submodules) to sys.modules
        * correctly nests submodules as needed
        """
        module_name = []
        for name in new_module.split('.'):
            m = ModuleType(name, doc)
            parent_module_name = '.'.join(module_name)
            if parent_module_name:
                setattr(sys.modules[parent_module_name], name, m)
            else:
                scope[name] = m
            module_name.append(name)
            sys.modules['.'.join(module_name)] = m
        return sys.modules['.'.join(module_name)]