[issue32501] Documentation for dir([object])

[Ethan Furman]

Change by Ethan Furman :


--
nosy: +ethan.furman

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32501] Documentation for dir([object])

[Matthew Cowles]

Matthew Cowles  added the comment:

My thanks to David for the clarification. I don't find the logic he describes 
(but does not necessarily subscribe to!) persuasive in this case. In my 
opinion, "Let's be incorrect for the sake of simplicity," is not the way to 
document a programming language in the language's official library 
documentation.

I think that saying, "If the object (technically the class) has a method 
named..." would add very little burden to people who don't care about the 
difference.

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32501] Documentation for dir([object])

[R. David Murray]

R. David Murray  added the comment:

I'm not sure, but the discussion I remember was that it would require changes 
to an awful lot of places in the docs that would make the docs harder to read.  
It is very seldom in normal Python coding that an object has a method that it 
does *not* get from its class, and by the time you get to the level where you 
are adding methods to instances it is likely you know about dunder methods only 
being looked up on classes.  Usually you learn about it the first time you try 
to put a dunder method on an instance, and you scratch your head for a while, 
and then you find out...but complicating the docs to mention this at every turn 
would be...excessive, I think.  But again, I'm not 100% sure I'm remembering 
the outcome of that conversation, and I can't remember where it took place (it 
was an issue in this tracker, but I don't know which one.)

--

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32501] Documentation for dir([object])

[Matthew Cowles]

Matthew Cowles  added the comment:

If David is right and people have previously decided not to change wording like 
this, can someone explain why? As it stands, the meaning is clear and incorrect.

--
nosy: +mdcowles

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32501] Documentation for dir([object])

[Eric V. Smith]

Eric V. Smith  added the comment:

It's described here: 
https://docs.python.org/3/reference/datamodel.html#special-lookup

Maybe we should have a glossary entry for "special method lookup", and somehow 
link mentions like __dir__ to it?

This is slightly different from 
https://docs.python.org/3/reference/datamodel.html#specialnames, which already 
has a glossary entry.

On the other hand, unless you already understand the problem, it's going to be 
difficult to search for it.

--
nosy: +eric.smith

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32501] Documentation for dir([object])

[R. David Murray]

R. David Murray  added the comment:

This is a general property of dunder methods in python3, and I think we have 
chosen not to change the wording when this has come up in other contexts.  I'm 
not sure, though.

--
nosy: +r.david.murray

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com

[issue32501] Documentation for dir([object])

[Vladislavs Burakovs]

New submission from Vladislavs Burakovs :

Documentation page [1]  says "If the object has a method named __dir__(), this 
method will be called and must return the list of attributes.". 

It seems that on Python 3.6 it only works if the *class* has a method named 
__dir__. Should the documentation be changed?

Microsoft Windows [Version 10.0.16299.192]
(c) 2017 Microsoft Corporation. All rights reserved.

D:\Users\wlad>python
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit 
(Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> class C: pass
...
>>> x = C()
>>> import types
>>> x.__dir__ = types.MethodType(lambda _:[], x)
>>> dir(x)
['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', 
'__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', 
'__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', 
'__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', 
'__str__', '__subclasshook__', '__weakref__']
>>> C.__dir__ = types.MethodType(lambda _:[], x)
>>> dir(x)
[]

[1] https://docs.python.org/3/library/functions.html

--
assignee: docs@python
components: Documentation
messages: 309544
nosy: Vladislavs Burakovs, docs@python
priority: normal
severity: normal
status: open
title: Documentation for dir([object])
type: enhancement
versions: Python 3.6

___
Python tracker 

___
___
Python-bugs-list mailing list
Unsubscribe: 
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com