Split out argparse.ArgumentParser into its own function

[josch]

This is useful for use with argcomplete or argparse-manpage.

For example, with this change a man page can be automatically generated from the information in the argparse object. It looks like this:

autotiling(1)                        General Commands Manual                        autotiling(1)

NAME
       autotiling

SYNOPSIS
       autotiling  [-h]  [-d]  [-v]  [-o  [OUTPUTS  ...]]  [-w  [WORKSPACES ...]] [-l LIMIT] [-sw
       SPLITWIDTH] [-sh SPLITHEIGHT] [-sr SPLITRATIO] [-e [EVENTS ...]]

DESCRIPTION
       Script for sway and i3 to automatically switch the horizontal / vertical
       window split orientation

OPTIONS
       -d, --debug
              print debug messages to stderr

       -v, --version
              display version information

[nwg-piotr]

Does it actually require use of a separate function (which will only be called once), or is it enough to provide positional arguments prog="autotiling", description="description"?

[josch]

I'm calling argparse-manpage like this:

argparse-manpage --pyfile=autotiling/main.py --function get_parser

The utility can only access the object returned by argparse.ArgumentParser if it's somehow publicly accessible and currently parser is a variable private to the main function.

[nwg-piotr]

Sounds like a justification, thanks.