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Subject: Re: [PATCH v2] kernel-doc: rename the kernel-doc directive
 'functions' to 'identifiers'
To:     Changbin Du <changbin.du@gmail.com>,
        Jani Nikula <jani.nikula@linux.intel.com>
Cc:     Jonathan Corbet <corbet@lwn.net>, linux-pci@vger.kernel.org,
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        Matthew Wilcox <willy@infradead.org>,
        Thomas Zimmermann <tzimmermann@suse.de>
References: <20191020131717.28990-1-changbin.du@gmail.com>
 <20191024121940.1d6a64df@lwn.net> <87woctb9cj.fsf@intel.com>
 <20191025144802.uixg2crhw6h7gghq@mail.google.com> <87v9s99q9l.fsf@intel.com>
 <20191029003120.llve32crfw63ovpw@mail.google.com>
From:   Markus Heiser <markus.heiser@darmarit.de>
Message-ID: <36c4dcfb-5425-b4bc-a5e9-4fd1458c8385@darmarit.de>
Date:   Tue, 29 Oct 2019 06:42:46 +0100
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Am 29.10.19 um 01:31 schrieb Changbin Du:
>> But is it, really? I agree with Jon about the distinction between None
>> and '' being confusing.
>>
> Here python is different from C. Both empty string and None are False in python.
> Note such condition is common in python.

The one is a empty string str(''), its bool('') value is False.

| >>> type(''), bool('')
| (<class 'str'>, False)

The other is a NoneType, its bool(None) value is False.

| >>> type(None), bool(None)
| (<class 'NoneType'>, False)

None often used like NULL (pointer). E.g if a function does not give an explicit 
return value, the returned value is None.

| >>> def foo():
| ...     pass
| ...
| >>> print(foo())
| None


-- Markus --