Explaining commands and positional arguments with --docopt

Question

This is the example from docopt.org:

Naval Fate.

Usage:
  naval_fate ship new <name>...
  naval_fate ship <name> move <x> <y> [--speed=<kn>]
  naval_fate ship shoot <x> <y>
  naval_fate mine (set|remove) <x> <y> [--moored|--drifting]
  naval_fate -h | --help
  naval_fate --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine.

I see that options can have a long explanation in the Options: section. For example, it's very clear that naval_fate --version is to Show version.

However, is there a way to provide an extended explanation for commands or positional arguments? For example, how does the user know what naval_fate ship shoot <x> <y> does?

score 5 · Answer 1 · answered Apr 17 '17 at 14:37

I arrived here with the same question, and I think I've figured out a solution.

The docopt docstring parser isn't very clever or rigorous, which is a good thing, as it means you can put all kinds of other information in your docstring without confusing docopt. For example, there's nothing to stop you adding Commands: or Arguments: sections to your docstring. Here's the docstring for the project I'm currently working on:

"""Helioplot.

Retrieve and plot heliometer results.

Usage:
    helioplot fetch <root_dir_path> --host=<host> --password=<password> [--port=<port>] [--database=<database>] [--username=<username>]

Commands:
    fetch <root_dir_path>   Fetch and dump data into the directory specified
                            by <root_dir_path>.

Options:
    -h --help               Show this screen.
    --version               Show version.
    --host=<host>           The address of the computer hosting the database
    --port=<port>           The port number on which the database can be
                            accessed.
    --database=<database>   The name of the database.
    --username=<username>   A database username.
    --password=<password>   The database password.
"""

Explaining commands and positional arguments with --docopt

1 Answers1