There's no need for shame! I regularly find out that there are Python features I didn't know about. It's called perpetual learning. :-)
On Sun, Sep 10, 2017 at 9:02 PM, INADA Naoki <songofaca...@gmail.com> wrote: > Oh, I'm shame myself. > > Only when `from email import *` is used, __all__ submodules are imported. > INADA Naoki <songofaca...@gmail.com> > > > On Mon, Sep 11, 2017 at 12:17 PM, Guido van Rossum <gu...@python.org> > wrote: > > I don't think submodules are automatically imported, unless there are > import > > statements in __init__.py. > > > > On Sun, Sep 10, 2017 at 8:08 PM, INADA Naoki <songofaca...@gmail.com> > wrote: > >> > >> It looks simple and easy to understand. > >> > >> To achieve lazy import without breaking backward compatibility, > >> I want to add one more rule: When package defines both of __getattr__ > and > >> __all__, automatic import of submodules are disabled (sorry, I don't > have > >> pointer to specification about this behavior). > >> > >> For example, some modules depends on email.parser or email.feedparser. > >> But since email/__init__.py uses __all__, all submodules > >> are imported eagerly. > >> > >> See > >> https://github.com/python/cpython/blob/master/Lib/email/ > __init__.py#L7-L25 > >> > >> Changing __all__ will break backward compatibility. > >> With __getattr__, this can be lazy import: > >> > >> import importlib > >> > >> def __getattr__(name): > >> if name in __all__: > >> return importlib.import_module("." + name, __name__) > >> raise AttributeError(f"module {__name__!r} has no attribute > {name!r}") > >> > >> > >> Regards, > >> > >> _______________________________________________ > >> Python-ideas mailing list > >> Python-ideas@python.org > >> https://mail.python.org/mailman/listinfo/python-ideas > >> Code of Conduct: http://python.org/psf/codeofconduct/ > >> > > > > > > > > -- > > --Guido van Rossum (python.org/~guido) > -- --Guido van Rossum (python.org/~guido)
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