Auto-generated help command does not appear in docstring

[JacekLach]

Thus, to know that program help <subcommand> will do anything I need to know that argh does something like this and that the tool being invoked uses argh.

help should generate the same kind of subcommand output in the short help that other subcommands do (perhaps with an usage string like help - get detailed help for a subcommand.

Workaround:

def help(subcommand):
     "Get detailed help for a subcommand"
     pass

dispatch_commands([..., help])

[neithere]

This makes sense.

Note that ./app.py help import xml also works but ./app.py import help xml doesn't.

Current implementation: actually there's no command help, it's always just a very simple top-level alias to ./app.py import xml --help. See https://github.com/neithere/argh/blob/master/argh/dispatching.py#L138

It works but it's not extensible. Fiddling with HelpFormatter is not a good idea because only its name is considered public API (see the argparse code).

We may be able to do it by adding a _HelpAction or a similar object to the parser. However, I'm not sure how exactly it should be done.

The autogenerated usage message should probably look like this:

usage: prog [-h] [help] {foo,bar} ...

...but how to put that [help] at that place, not after mandatory args?

Gotta try some time later, I guess.