Do not print empty long program option name

[vlad@…]

This patch partially solves the problem when there is only short option name for the parameter and option_description class generates ugly help message. For example -

{{{(",w", po::value<int>(), "Perfrom write with N frames")}}}

generates this

{{{-w [ -- ] arg : Perfrom write with N frames}}}

The "[ -- ]" part is confusing. So if long option name is empty, we don't print that part.

Ideally, we should also print one dash for single character long option name if command_line_style::allow_long_disguise is specified, but I can't find a way to access those styles from option_description.

Originally, the problem found by a guy at Stack Overflow - ​http://stackoverflow.com/questions/3621181/short-options-only-in-boostprogram-options

[vlad@…]

Diff for the option_description fix

[Vladimir Prus]

(In [65645]) Fix formatting of short-only options.

Fixes #4644.

[Vladimir Prus]

Thanks for the patch, I've checked it in. About style and long disguise -- I'm not sure we can do anything, because the parsing style is only know when we actually parse things.

[anonymous]

The patch is not in release 1.49.0!?

[anonymous]

Is there any chance that this feature request will be included into a release. I won't call this a showstopper but still would this make the library more complete from a library user point of view.

[Vladimir Prus]

Ehm, that patch is in the release branch. Since 2012-04-08. So not only it's included in next release, but also in the last one.