[Python-ideas] Allow from foo import bar*

[Giampaolo Rodola']

> 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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