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