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Groups > comp.lang.python > #90497
| From | Terry Reedy <tjreedy@udel.edu> |
|---|---|
| Subject | Re: Python file structure |
| Date | 2015-05-12 17:34 -0400 |
| References | <f25aa9d4-4025-457d-8072-5327c98db1bd@googlegroups.com> <026e6357-917c-4d50-b70f-70903aa0e065@googlegroups.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.421.1431466492.12865.python-list@python.org> (permalink) |
On 5/12/2015 3:49 PM, Ned Batchelder wrote: > On Tuesday, May 12, 2015 at 3:13:32 PM UTC-4, zljubi...@gmail.com wrote: >> Hi, I have python file with the following structure: >> >> import... >> >> A = configparser.get(...) >> B = configparser.get(...) >> >> Command line parameters parsing [they can change variable A or B] >> >> Def usage() >> Print how to use script parameters >> >> def main(): >> ... >> >> if __name__ == "__main__": >> main() >> >> If I find an error in command line parameters section I cannot call function usage() because it is not defined yet. >> >> I have few options here: >> 1. Put definition of usage function before command line parameters parsing section >> 2. Make parameters global and put them in the main function >> 3. ...maybe some other options... >> > > I would put all of the code into a function some place. Don't have > anything at the top level of the file except imports, function (and > class) definitions, and an "if __name__....." clause at the bottom. I was about to suggest the same. One advantage of 'write tests first' is that you force yourself to write testable code from the beginning, instead of refactoring later. > If you need to use globals, assign them inside a parse_arguments > function that has a "global" statement in it. Better not to have mutable module globals if you can avoid it. If you want application globals, put them in a separate module. > As a side note, if you are going to have code at the top-level of > the file, then there's no point in the "if __name__..." clause. > That clause is designed to make a file both runnable and importable. > But your top-level code makes the file very difficult to import. And you need to import to test. -- Terry Jan Reedy
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Python file structure zljubisicmob@gmail.com - 2015-05-12 12:13 -0700
Re: Python file structure Chris Angelico <rosuav@gmail.com> - 2015-05-13 05:29 +1000
Re: Python file structure Ned Batchelder <ned@nedbatchelder.com> - 2015-05-12 12:49 -0700
Re: Python file structure zljubisicmob@gmail.com - 2015-05-12 12:58 -0700
Re: Python file structure Dave Angel <davea@davea.name> - 2015-05-12 16:43 -0400
Re: Python file structure Chris Angelico <rosuav@gmail.com> - 2015-05-13 06:02 +1000
Re: Python file structure Terry Reedy <tjreedy@udel.edu> - 2015-05-12 17:34 -0400
Re: Python file structure Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-12 13:54 -0600
Re: Python file structure Chris Angelico <rosuav@gmail.com> - 2015-05-13 06:07 +1000
Re: Python file structure Tim Chase <python.list@tim.thechases.com> - 2015-05-13 13:34 -0500
Re: Python file structure Chris Angelico <rosuav@gmail.com> - 2015-05-14 12:03 +1000
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