# Code copied from
# https://github.com/tensorflow/tensorflow/blob/master/tensorflow/python/util/lazy_loader.py
import importlib
import types
[docs]class LazyLoader(types.ModuleType):
"""Lazily import a module, mainly to avoid pulling in large dependencies.
This allows them to only be loaded when they are used.
"""
def __init__(self, local_name, parent_module_globals, name):
self._local_name = local_name
self._parent_module_globals = parent_module_globals
super(LazyLoader, self).__init__(name)
def _load(self):
"""Load the module and insert it into the parent's globals."""
# Import the target module and insert it into the parent's namespace
try:
module = importlib.import_module(self.__name__)
except ModuleNotFoundError as e:
raise ModuleNotFoundError(
f"Lazy module loader cannot find module "
f"named `{self.__name__}`. "
f"This might be because textflint does not automatically "
f"install some optional dependencies. "
f"Please run `pip install {self.__name__}` "
f"to install the package.") from e
self._parent_module_globals[self._local_name] = module
# Update this object's dict so that if someone keeps a reference to the
# LazyLoader, lookups are efficient
# (__getattr__ is only called on lookups
# that fail).
self.__dict__.update(module.__dict__)
return module
def __getattr__(self, item):
module = self._load()
return getattr(module, item)
def __dir__(self):
module = self._load()
return dir(module)