Spaces in default value about docopt-ng HOT 3 OPEN

This seems like a reasonable idea, but I would want to get it right, and there are a few rough cases:

• how to do escaping. For instance I might want the string Dwayne "The Rock" Johnson. This should be easily explainable.
• how to deal with escaping. eg if the string contains a ] then the current re.findall(r"\[default: (.*)\]") would fail. Of course, this also currently fails if you want a ] in your default, but currenlty it is a bit more obvious that this should fail. Once you add quoting, I think we would need this to work.

Once we figure those out, and add tests and docs, then it sounds great!

from docopt-ng.

Indeed I see the Pandora's box of string quoting.

The way I implemented in #47 cowardly avoid having to deal with it. It works as previously: re.findall(r"\[default: (.*)\]") but it just adds a check after the match is successful. If it is the case that the match starts and ends with the same quote character (both single or both double) than it strips them and that's it.

This example just works and result in Dwayne "The Rock" Johnson:

--main-actor=<name>    name of the movie's main actor  [default: Dwayne "The Rock" Johnson]

This might not be intuitive or elegant but it is easy to use and always has a solution, even for strings that do start and end with quotes:

• enclose it with "the other" quote character [default: '"The Rock"']
• enclose it with "the same" quote character [default: ""The Rock""]

However, confusion may arise when users of the library might not expect quoting to be implemented and, expecting "The Rock", writes this:

--main-actor-nickname=<name>   name of the movie's main actor  [default: "The Rock"]

One way around it would be to

1. specifically enable this feature when needed: arguments = docopt(__doc__, quoted_defaults=True)
2. document it properly and expect developers using the library to apply extra care when dealing with quotes anyway

from docopt-ng.

As for string containing ], because .* is greedy, it doesn't pose any problem I reckon. The following example already works as expected (resulting in []) with or without quoting.

--group-enclosure=<pair>             open/close grouping characters [default: []]

from docopt-ng.