Skip to content

Instantly share code, notes, and snippets.

What would you like to do?
__lazy__ importing
import sys
from types import ModuleType
__path__ = []
LAZY_PREFIX = "__lazy__"
class OnDemandModule(ModuleType):
def __init__(self, name):
ModuleType.__init__(self, name)
object.__setattr__(self, "__module", None)
def _get_module(self):
if object.__getattribute__(self, "__module"):
return object.__getattribute__(self, "__module")
mod = __import__(self.__name__, None, None, "*")
object.__setattr__(self, "__module", mod)
object.__setattr__(self, "__doc__", mod.__doc__)
object.__setattr__(self, "__file__", mod.__file__)
if hasattr(mod, "__path__"):
object.__setattr__(self, "__path__", mod.__path__)
return mod
def __dir__(self):
return dir(self._get_module())
def __repr__(self):
if object.__getattribute__(self, "__module"):
return repr(self._get_module())
return "<%s '%s'>" % (self.__class__.__name__, self.__name__)
def __getattr__(self, name):
return getattr(self._get_module(), name)
def __delattr__(self, name):
return delattr(self._get_module(), name)
def __setattr__(self, name, value):
return setattr(self._get_module(), name, value)
class LazyImporter(object):
def find_module(self, fullname, path = None):
if fullname.startswith(LAZY_PREFIX + "."):
return self
return None
def load_module(self, fullname):
realname = fullname[len(LAZY_PREFIX) + 1:]
if realname in sys.modules:
return sys.modules[realname]
if fullname in sys.modules:
return sys.modules[fullname]
mod = sys.modules[fullname] = OnDemandModule(realname)
return mod
_the_lazy_importer = LazyImporter()
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment