Friday Finking: Source code organisation

[DL Neil]

On 29/12/19 5:49 PM, Cameron Simpson wrote:
> On 29Dec2019 09:49, Chris Angelico <rosuav at gmail.com> wrote:
>> "Define before use" is a broad principle that I try to follow, even
>> when the code itself doesn't mandate this. This generally means that
>> "if name is main" is the very last thing in the file, and if there's a
>> main() function or equivalent, that's usually just before that. Any
>> metaprogramming goes right at the top; sometimes this is mandated (if
>> I write a decorator function, it has to be above the functions it's
>> decorating), but even if it's not, metaprogramming goes before the
>> mainline.
> 
> For main, i have the opposite habit. If a module has a main() function 
> for command line use I usually want that right up the front:
> 
>   #!/usr/bin/env python3
>   ....
>   import...
> 
>   def main(argv=None):
>     ... main command line ...
> 
>   classes, functions, etc
> 
>   if __name__ == '__main__':
>     sys.exit(main(sys.argv))
> 
> My reasoning here is that I want the main programme obvious up front.
> 
> But then I loosely follow "define before use" after that.


OK, I'll bite:

1 the reader (one assumes) starts at the top, then scrolls all the way 
to the bottom to find if...__main___, but is then directed to search for 
the def main... which is all the way back up to the top!

2 if instead of a main(), that code was under if ... __main__ would that 
be an equally reasonable and "obvious" place to find it?

-- 
Regards =dn