Access add_subparsers() kwargs

[bsandrow]

Specifically the ability to pass in things like the metavar keyword. It would be nice to just pass metavar='COMMAND' to add_subparsers() rather than getting using a list of all commands as a metavar. This looks really ugly when you have 10+ commands, and it's straining to fit them all into the {,} list.

[jeffwidman]

@bsandrow afraid I'm not familiar with the metavar keyword, can you expand on what metavar='COMMAND' means?

I'm open to merging if it's useful functionality, just want to make sure I understand what's actually being added here.

[bsandrow]

metavar= controls what shows up in the usage string. For example:

parser.add_argument('-f', '--file', metavar='INPUT_FILE')

would show something like:

usage: program [--file INPUT_FILE]

rather than

usage: program [--file FILE]

which would be the default.

When it comes to subparsers, you usually end up with something like this by default:

usage: program {command_1, command_2, command_3}

This gets awkward-looking if you have a lot of commands, but if you pass the metavar= option, you can have something like:

usage: program COMMAND

Note that it's also used in the command list of help as well. metavar is a placeholder that is used anywhere that the help text needs a placeholder to reference where the value would go.

[jeffwidman]

Thanks, that's a great explanation.