Output default value with help text

[PhilippPaetzold]

Hi @p-ranav,

I think it would be nice, if you could print default values specified by "default_value" method when outputting the help text:

    program
        .add_argument("n")
        .help("Number of iterations to be performed")
        .default_value("10");

->

...
Positional arguments:
n               Number of messages to be sent (default: 10)

this would be really useful

Best regards
Philipp

[rysson]

Nice idea, optional of course.

[mishmish-dev]

Hey, I made a PR
#92

I'm not sure if I should include some extra tests/demos.

Under the hood it uses details::repr function to get string representation of default argument, which uses to << operator to std::ostream. It also works with basic STL-like containers, printing not more than details::repr_max_container_size elements (hardcoded to 5).

Basically, it solves the issue, but still, I haven't figured out what to do with long strings as well as those containing newlines and special symbols.

[p-ranav]

I've approved the PR but yes, a few tests are required, e.g.,

• default arg that is integral
• default arg that is float
• default arg that is string
• default arg that is vector
• default arg that is bool
• default arg that is optional