51 lines
1.6 KiB
Python
51 lines
1.6 KiB
Python
|
import importlib
|
||
|
|
|
||
|
|
|
||
|
|
def relative_import(parent_name, rel_modules=(), rel_classes=()):
|
||
|
|
"""
|
||
|
|
Helper function to import submodules lazily in Python 3.7+
|
||
|
|
|
||
|
|
Parameters
|
||
|
|
----------
|
||
|
|
rel_modules: list of str
|
||
|
|
list of submodules to import, of the form .submodule
|
||
|
|
rel_classes: list of str
|
||
|
|
list of submodule classes/variables to import, of the form ._submodule.Foo
|
||
|
|
|
||
|
|
Returns
|
||
|
|
-------
|
||
|
|
tuple
|
||
|
|
Tuple that should be assigned to __all__, __getattr__ in the caller
|
||
|
|
"""
|
||
|
|
module_names = {rel_module.split(".")[-1]: rel_module for rel_module in rel_modules}
|
||
|
|
class_names = {rel_path.split(".")[-1]: rel_path for rel_path in rel_classes}
|
||
|
|
|
||
|
|
def __getattr__(import_name):
|
||
|
|
# In Python 3.7+, lazy import submodules
|
||
|
|
|
||
|
|
# Check for submodule
|
||
|
|
if import_name in module_names:
|
||
|
|
rel_import = module_names[import_name]
|
||
|
|
return importlib.import_module(rel_import, parent_name)
|
||
|
|
|
||
|
|
# Check for submodule class
|
||
|
|
if import_name in class_names:
|
||
|
|
rel_path_parts = class_names[import_name].split(".")
|
||
|
|
rel_module = ".".join(rel_path_parts[:-1])
|
||
|
|
class_name = import_name
|
||
|
|
class_module = importlib.import_module(rel_module, parent_name)
|
||
|
|
return getattr(class_module, class_name)
|
||
|
|
|
||
|
|
raise AttributeError(
|
||
|
|
"module {__name__!r} has no attribute {name!r}".format(
|
||
|
|
name=import_name, __name__=parent_name
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
__all__ = list(module_names) + list(class_names)
|
||
|
|
|
||
|
|
def __dir__():
|
||
|
|
return __all__
|
||
|
|
|
||
|
|
return __all__, __getattr__, __dir__
|