Just a quick question about main()

[Grant Edwards]

On 2017-10-27, Chris Angelico <rosuav at gmail.com> wrote:
> On Sat, Oct 28, 2017 at 5:05 AM, ROGER GRAYDON CHRISTMAN <dvl at psu.edu> wrote:
>> While teaching my introductory course in Python, I occasionally see
>> submissions containing the following two program lines,[...]

>> if __name__ = '__main__':
>> ...  main()

> If it's JUST for unit tests, I'd expect no main(), but instead to have
> it go straight into unittest.main(). IMO, the construct you show there
> implies three things:
>
> 1) This module is intended to be run from the command line
> 2) This module is intended to be imported by other modules
> 3) If imported by another module, this can also be invoked as if it
>    were the top-level app.

I sometimes create a main function out of habit even if I can't
imagine a case #3.

A typical situation that I often encounter is that I write a set of
functions to perform some task(s) via a serial or network connection
using some industrial protocol.  [For example, updating firmware in a
device.]

There are often two use cases:

1) It can be used from the command-line as a stand-alone application
   with various command line options and arguments that specify the
   operation[s] to be performed. 

2) It can be imported by a GUI application in order to provide to the
   GUI framework code the functions that can be called to do the
   individual operations.

Even if the real-world end-user use case is purely the GUI one, it's
often far easier and faster to also include a main() for deveopment
and testing of the functions provided to the GUI.

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