Meaning of def(_f) and del(_f) at the beginning of ABC collections

Asked Dec 31 '21 at 13:54

Active Jan 03 '22 at 14:46

Viewed 48 times

Just went across internals of ABC collections.

Can anyone please explain what does this construct stand for:

def _f(): pass
FunctionType = type(_f)
del _f

I know I'm probably missing some basic concept(s), please advise where to start/look to understand this?

edited Jan 03 '22 at 14:46

Dobromir Kovachev

asked Dec 31 '21 at 13:54

vtm11

2

`FunctionType` is supposed to represent the type that functions are. The easiest way for python to record what type a function is, is to create one, _check_ what type it is, and then delete it so that it's not polluting the namespace. – Green Cloak Guy Dec 31 '21 at 13:55
1

@GreenCloakGuy Any idea why it doesn't do `FunctionType = type(lambda: None)` instead? – Kelly Bundy Jan 03 '22 at 14:57
1

Presumably because, at some point in the feature, lambdas may become a meaningfully different type than functions, and in that case they'd want to put that in a separate type variable `LambdaType` instead. – Green Cloak Guy Jan 03 '22 at 15:07

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