[Python-ideas] Replacing the if __name__ == "__main__" idiom (was Re: making a module callable)

[Sean McQuillan]

Adding a mainfunction decorator was mentioned in the other thread, seemed
interesting so I coded up a simple example to see how it works.

https://github.com/objcode/mainfunction/blob/master/mainfunction/mainfunction.py

>From the README:

@mainfunction
def main():
    print "Hello, World."

vs:

if __name__ == '__main__':
   print "Hello, World."


After playing with it briefly, I'm not sure it's a clear spelling win as
decorators are a fairly advanced topic to a new programmer. If statements
are one of the first programming constructs a new programmer learns - and
they don't leave a "magic taste".

Thoughts?


On Fri, Nov 22, 2013 at 3:47 PM, Rob Cliffe <rob.cliffe at btinternet.com>wrote:

>
> On 22/11/2013 22:27, Eric Snow wrote:
>
>> On Fri, Nov 22, 2013 at 3:02 PM, David Mertz <mertz at gnosis.cx> wrote:
>>
>>> I'm not in love with the *spelling* of " if __name__=='__main__': ", but
>>> I
>>> very frequently use the overall pattern.
>>>
>>> Much--or even most--of the time when I write a module, I like to allow
>>> it to
>>> either do a minimal case of its basic functionality and/or have the
>>> module
>>> run some basic unit tests as a quick check against breakage.  So in
>>> contrast
>>> to Eric Snow, I try *to* make my files both scripts and modules.  I know
>>> this isn't the only possible approach, but I don't think it's bad or
>>> uncommon.
>>>
>> You're right and I think it's a good pattern too.  That is something
>> we do in the stdlib (and increasingly so).  It slipped my mind.  I've
>> also seen the idiom used for initiating tests (not that I necessarily
>> condone that practice), though less so in large projects.  It would be
>> nice if we could address the issues outlined in PEP 395.
>>
> Yes.  Having functionality and some test of that functionality in the same
> module simplifies file organisation/maintenance.  The test typically also
> provides extra documentation of the functionality ("this is how you use
> it").
>
> Rob Cliffe
>
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-- 
Sean McQuillan
415.990.0854
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