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Re: "Don't rebind built-in names*" - it confuses readers

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  Re: "Don't rebind built-in names*" - it confuses readers Peter Otten <__peter__@web.de> - 2013-06-11 09:09 +0200
    Re: "Don't rebind built-in names*" - it confuses readers rusi <rustompmody@gmail.com> - 2013-06-11 04:12 -0700
      Re: "Don't rebind built-in names*" - it confuses readers Peter Otten <__peter__@web.de> - 2013-06-11 14:06 +0200
      Re: "Don't rebind built-in names*" - it confuses readers Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-11 13:34 +0000
        Re: "Don't rebind built-in names*" - it confuses readers Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-11 08:43 -0700
          Re: "Don't rebind built-in names*" - it confuses readers Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-11 17:29 +0100

#47643 — Re: "Don't rebind built-in names*" - it confuses readers

Terry Jan Reedy wrote:

> Many long-time posters have advised "Don't rebind built-in names*.

I'm in that camp, but I think this old post by Guido van Rossum is worth 
reading to put the matter into perspective:

"""
> That was probably a checkin I made.  I would have left it alone except the
> code was
> 
>     file = open(...)
> 
> As long as I was changing the variable name to not mask the builtin I
> changed the call as well.  Had it been
> 
>     f = open(...)
> 
> I probably would have kept my hands off.

Hm...  I'm not particularly concerned over fixing all code that uses
file as a local variable name, unless it actually is likely to need to
reference the file class by name; builtins are in the last scope
searched for the very reason that no programmer is expected to keep up
with all additions to the built-in library, so locals hiding built-ins
is okay.  (Not that it isn't a good idea to avoid obvious clashes --
'str' for string variables and 'type' for type variables being the
most obvious stumbling blocks.)

> In any case, I was under the impression that file() was the wave of the
> future and open() a nod to the past.

Now you know better...

--Guido van Rossum (home page: http://www.python.org/~guido/)
"""

<http://mail.python.org/pipermail/python-dev/2004-July/045948.html>

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#47653

On Jun 11, 12:09 pm, Peter Otten <__pete...@web.de> wrote:
> Terry Jan Reedy wrote:
> > Many long-time posters have advised "Don't rebind built-in names*.
>
> I'm in that camp, but I think this old post by Guido van Rossum is worth
> reading to put the matter into perspective:

Not sure what you are saying Peter… If it is this (taken without
context):

> (Not that it isn't a good idea to avoid obvious clashes --
> 'str' for string variables and 'type' for type variables being the
> most obvious stumbling blocks.)

then I guess we are saying the same thing??

If however we consider the context of that message:
First there was only open, then there came file, and file was
considered better than open, now again file seems to have disappeared
from python3… and this message is written in the context of making the
'kosherness' of one python generation become the *different*
kosherness of the next…

then what the message of the Guido-quote is, is not clear (at least to
me).

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#47657

rusi wrote:

> On Jun 11, 12:09 pm, Peter Otten <__pete...@web.de> wrote:
>> Terry Jan Reedy wrote:
>> > Many long-time posters have advised "Don't rebind built-in names*.
>>
>> I'm in that camp, but I think this old post by Guido van Rossum is worth
>> reading to put the matter into perspective:
> 
> Not sure what you are saying Peter… If it is this (taken without
> context):
> 
>> (Not that it isn't a good idea to avoid obvious clashes --
>> 'str' for string variables and 'type' for type variables being the
>> most obvious stumbling blocks.)
> 
> then I guess we are saying the same thing??
> 
> If however we consider the context of that message:
> First there was only open, then there came file, and file was
> considered better than open, now again file seems to have disappeared
> from python3… and this message is written in the context of making the
> 'kosherness' of one python generation become the *different*
> kosherness of the next…
> 
> then what the message of the Guido-quote is, is not clear (at least to
> me).

As I understand it we should be a bit more relaxed about the matter of 
shading builtins with local variables than we usually are ;)

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#47660

On Tue, 11 Jun 2013 04:12:38 -0700, rusi wrote:

[...]
> then what the message of the Guido-quote is, is not clear (at least to
> me).

The relevant part is in the bit that you deleted. Let me quote it for you 
again:

    "locals hiding built-ins is okay"
    -- Guido van Rossum, inventor and BDFL of Python

[deadpan]
Sorry for such a long quote, and I realise it's quite tricky to 
interpret, so let me summarise for anyone still having difficulty:

GvR is saying that it's okay to use the names of built-in functions or 
types as the names of local variables, even if that causes the built-in 
to be inaccessible within that function.


-- 
Steven

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#47668

On Tuesday, June 11, 2013 8:34:55 AM UTC-5, Steven D'Aprano wrote:

> GvR is saying that it's okay to use the names of built-in functions or 
> types as the names of local variables, even if that causes the built-in 
> to be inaccessible within that function.

Looks like we've finally found the traitor! Code smells propagating down from the apex of the pyramid... well thanks for the wonderful advice Guido, and with it you've cursed Python's stdlib to another decade of unprofessional code! 

PS: Excuse me whilst i brew myself a nice cup of HEMLOCK TEA!!! ಠ_ಠ

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#47674

On 11/06/2013 16:43, Rick Johnson wrote:
> On Tuesday, June 11, 2013 8:34:55 AM UTC-5, Steven D'Aprano wrote:
>
>> GvR is saying that it's okay to use the names of built-in functions or
>> types as the names of local variables, even if that causes the built-in
>> to be inaccessible within that function.
>
> Looks like we've finally found the traitor! Code smells propagating down from the apex of the pyramid... well thanks for the wonderful advice Guido, and with it you've cursed Python's stdlib to another decade of unprofessional code!
>
> PS: Excuse me whilst i brew myself a nice cup of HEMLOCK TEA!!! ಠ_ಠ
>

At long last I've received some good news.  But blast it, you've only 
said you'll brew it, not that you'll drink it.  Still, I can but hope.

-- 
"Steve is going for the pink ball - and for those of you who are 
watching in black and white, the pink is next to the green." Snooker 
commentator 'Whispering' Ted Lowe.

Mark Lawrence

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