Message 365783 - Python tracker

Message365783

Author	serhiy.storchaka
Recipients	gvanrossum, levkivskyi, serhiy.storchaka
Date	2020-04-04.21:08:44
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1586034525.17.0.360408189871.issue40185@roundup.psfhosted.org>
In-reply-to

Content
typing.NamedTuple is used in two ways. 1. It is a callable which produces a new namedtuple type. 2. It can also be used as a base in the class statement for creating a new namedtuple type. In both cases it is not a real class. You cannot create an instance of NamedTuple or a subclass of NamedTuple. But it is implemented as a class, and help() shows methods and data descriptors for it, which are useless. The proposed PR implements NamedTuple like a function. Implementation of the __mro_entries__ method allows to use it as a base in the class statement.

Content

typing.NamedTuple is used in two ways.

1. It is a callable which produces a new namedtuple type.
2. It can also be used as a base in the class statement for creating a new namedtuple type.

In both cases it is not a real class. You cannot create an instance of NamedTuple or a subclass of NamedTuple. But it is implemented as a class, and help() shows methods and data descriptors for it, which are useless.

The proposed PR implements NamedTuple like a function. Implementation of the __mro_entries__ method allows to use it as a base in the class statement.

History
Date	User	Action	Args
2020-04-04 21:08:45	serhiy.storchaka	set	recipients: + serhiy.storchaka, gvanrossum, levkivskyi
2020-04-04 21:08:45	serhiy.storchaka	set	messageid: <1586034525.17.0.360408189871.issue40185@roundup.psfhosted.org>
2020-04-04 21:08:45	serhiy.storchaka	link	issue40185 messages
2020-04-04 21:08:44	serhiy.storchaka	create