Re: [boost] [program_options] Feature request: settable argument names

From: Vladimir Prus (ghost_at_[hidden])
Date: 2007-10-17 11:21:39

Joe Gottman wrote:

> 
>     I recently used the program_options library for the first time and
> found it very useful. However, there's one easily implemented feature
> that's missing: the ability to set the name of a parameter that's
> associated with a particular option.  In the first example in the
> tutorial we have the code
> 
> po::options_description desc("Allowed options");
> desc.add_options()
>      ("help", "produce help message")
>      ("compression", po::value<int>(), "set compression level")
> ;
> 
> When desc is then sent to cout, the output then looks like
> 
> Allowed options:
> --help                 : produce help message
> --compression arg      : set compression level
> 
> 
>     But suppose we wanted the name of the parameter associated with the
> --compression option to be something other than arg.  

I intentionally did not add that bit of flexibility, as I though that
configurable 'arg' is not adding all that much to legibility. Do you have
some concrete examples?

> If this function were included, then the code above could be rewritten as
> 
> po::options_description desc("Allowed options");
> desc.add_options()
>      ("help", "produce help message")
>      ("compression", po::value<int>()->argument_name("level-number"),
> "set compression level")
> ;
> 
> and then the output would be
> 
> Allowed options:
> --help                 : produce help message
> --compression level-number      : set compression level

Well, here, I don't like the duplication between 'level' and 'level-number'
Maybe it would be cleaner to have just:

  --compression arg      : set compression level (0-9)

or some such? 

- Volodya