[Python-ideas] Allow from foo import bar*

[Ryan Gonzalez]

Well, that looks painful! I agree with Joshua: If you are doing something
like that, namespaces work best. If you're really that desperate, why not
something like this:

globals().update({name: getattr(_psplatform, name) for name in
dir(_psplatform) if name.startswith('RLIMIT')})


On Thu, Oct 3, 2013 at 1:43 PM, Giampaolo Rodola' <g.rodola at gmail.com>wrote:

> > Hm. Why not just use "import socket" and then use "socket.AF_<whatever>"?
>
> That's what I usually do as well (because explicit is better than
> implicit) but from my understanding when it comes to constants it is
> generally not considered a bad practice to import them directly into the
> module namespace.
> I guess my specific case is bit different though.
> I have all these constants defined in a _linux.py submodule which I import
> from __init__.py in order to expose them publicly.
> And this is how I do that:
>
>     # Linux >= 2.6.36
>     if _psplatform.HAS_PRLIMIT:
>         from psutil._pslinux import (RLIM_INFINITY, RLIMIT_AS, RLIMIT_CORE,
>                                      RLIMIT_CPU, RLIMIT_DATA, RLIMIT_FSIZE,
>                                      RLIMIT_LOCKS, RLIMIT_MEMLOCK,
> RLIMIT_NOFILE,
>                                      RLIMIT_NPROC, RLIMIT_RSS,
> RLIMIT_STACK)
>         if hasattr(_psplatform, "RLIMIT_MSGQUEUE"):
>             RLIMIT_MSGQUEUE = _psplatform.RLIMIT_MSGQUEUE
>         if hasattr(_psplatform, "RLIMIT_NICE"):
>             RLIMIT_NICE = _psplatform.RLIMIT_NICE
>         if hasattr(_psplatform, "RLIMIT_RTPRIO"):
>             RLIMIT_RTPRIO = _psplatform.RLIMIT_RTPRIO
>         if hasattr(_psplatform, "RLIMIT_RTTIME"):
>             RLIMIT_RTTIME = _psplatform.RLIMIT_RTTIME
>         if hasattr(_psplatform, "RLIMIT_SIGPENDING"):
>             RLIMIT_SIGPENDING = _psplatform.RLIMIT_SIGPENDING
>
>
> In *this specific case* a "from _psplatform import RLIM*" would have
> solved my problem nicely.
> On one hand this might look like encouraging wildcard import usage, but I
> think it's the opposite.
> Sometimes people use "from foo import *" just because "from foo import
> bar*" is not available.
>
>
> --- Giampaolo
> https://code.google.com/p/pyftpdlib/
> https://code.google.com/p/psutil/
> https://code.google.com/p/pysendfile/
>
>
> On Thu, Oct 3, 2013 at 7:16 PM, Guido van Rossum <guido at python.org> wrote:
>
>> Hm. Why not just use "import socket" and then use "socket.AF_<whatever>"?
>>
>>
>> On Thu, Oct 3, 2013 at 10:09 AM, Giampaolo Rodola' <g.rodola at gmail.com>wrote:
>>
>>> I suppose this has already been proposed in past but couldn't find
>>> any online  reference so here goes.
>>> When it comes to module constant imports I usually like being explicit
>>> it's OK with me as long as I have to do:
>>>
>>> >>> from resource import (RLIMIT_CORE, RLIMIT_CPU, RLIMIT_FSIZE)
>>>
>>> Nevertheless in case the existence of certain constants depends on the
>>> platform in use I end up doing:
>>>
>>> >>> if hasattr(resource, "RLIMIT_MSGQUEUE"):  # linux only
>>> ....         import resource.RLIMIT_MSGQUEUE
>>> ....
>>> >>> if hasattr(resource, "RLIMIT_NICE"):  # linux only
>>> ....         import resource.RLIMIT_NICE
>>> ....
>>>
>>>
>>> ...or worse, if for simplicity I'm willing to simply import all RLIMIT_*
>>> constants I'll have to do this:
>>>
>>> >>> import resource
>>> >>> import sys
>>> >>> for name in dir(resource):
>>> ....    if name.startswith('RLIMIT_'):
>>> ....        setattr(sys.modules[__name__], name, getattr(resource, name))
>>>
>>> ...or just give up and use:
>>>
>>> from resource import *
>>>
>>> ...which of course will pollute the namespace with unnecessary stuff.
>>> So why not just allow "from resource import RLIMIT_*" syntax?
>>> Another interesting variation might be:
>>>
>>>
>>> >>> from socket import AF_*, SOCK_*
>>> >>> AF_INET, AF_INET6, SOCK_STREAM, SOCK_DGRAM
>>> (2, 10, 1, 2)
>>>
>>>
>>> On the other hand mixing "*" and "common" imports would be forbidden:
>>>
>>> >>> from socket import AF_*, socket,
>>>   File "<stdin>", line 1
>>>     from socket import AF_*, socket
>>>                                          ^
>>> SyntaxError: invalid syntax;
>>>
>>>
>>> Thoughts?
>>>
>>>
>>> --- Giampaolo
>>> https://code.google.com/p/pyftpdlib/
>>> https://code.google.com/p/psutil/
>>> https://code.google.com/p/pysendfile/
>>>
>>> _______________________________________________
>>> Python-ideas mailing list
>>> Python-ideas at python.org
>>> https://mail.python.org/mailman/listinfo/python-ideas
>>>
>>>
>>
>>
>> --
>> --Guido van Rossum (python.org/~guido)
>>
>
>
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>


-- 
Ryan
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