Better option for options (pun intended) about cxx20opts HOT 3 OPEN

As I can see, there has been already implemented pipe syntax like this:

auto options = libname::options{ argc, argv }
    | libname::option( /* ... */ )
    | libname::option( /* ... */ );

With ADL, we can remove redundant libname mentions and improve readability:

auto options = libname::options{ argc, argv }
    | option( /* ... */ )
    | option( /* ... */ );

But I'm not sure if this is a reliable tool. And I think, it's also possible to improve the first example and make it similar to the previous one:

auto options = libname::options{ argc, argv }
    .option( /* ... */ )
    .option( /* ... */ );

Isn't this the best from both worlds?

If in a future we want to have option groups, your second example might be changed to:

auto options = libname::options {
    libname::option( /* ... */ ), 
    libname::group("groupname"
        libname::option( /* ... */ ), 
        libname::option( /* ... */ ))
    libname::option( /* ... */ ),
};

And with my proposal to:

auto options = libname::options { argc, argv }
    .option( /* ... */ )
    .group("groupname")
        .option( /* ... */ )
        .option( /* ... */ )
    .close()
    .option( /* ... */ );

And I think it's more expressive syntax. But there may also be some drawbacks that I'm not seeing and these are only theoretical thoughts at now

from cxx20opts.

Yes, it is planned to make builder-like syntax. But there’s no time yet :(

from cxx20opts.

You can also add a constructor overload, with a variadic of options. Easy.
For:

auto options = libname::options{option, option, option, option};

But there is no free time at the moment :(

from cxx20opts.