45 lines
1.3 KiB
Python
45 lines
1.3 KiB
Python
# Copyright 2022 The JAX Authors.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""A LazyLoader class."""
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import importlib
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from typing import Any, Callable, List, Sequence, Tuple
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def attach(package_name: str, submodules: Sequence[str]) -> Tuple[
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Callable[[str], Any],
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Callable[[], List[str]],
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List[str],
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]:
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"""Lazily loads submodules of a package.
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Example use:
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```
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__getattr__, __dir__, __all__ = lazy_loader.attach(__name__, ["sub1", "sub2"])
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```
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"""
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__all__: List[str] = list(submodules)
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def __getattr__(name: str) -> Any:
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if name in submodules:
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return importlib.import_module(f"{package_name}.{name}")
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raise AttributeError(f"module '{package_name}' has no attribute '{name}")
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def __dir__() -> List[str]:
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return __all__
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return __getattr__, __dir__, __all__
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