Re: [Boost-users] [Boost.Program_options] extra_parser for config files

Subject: Re: [Boost-users] [Boost.Program_options] extra_parser for config files
From: Vladimir Prus (vladimir_at_[hidden])
Date: 2009-07-10 06:37:10

Marti Cuquet wrote:

> Hi,
> 
> I want to implement the --switch / --no-switch behavior.
> 
> I defined a bool option "switch" and then I parse the command line with
> an extra parser that sets "switch" to "false" if it finds a --no-switch.
> 
> myopts.add_options()
>   ("switch", po::value<bool>()->implicit_value(true), "Use switch.")
> ;
> po::store (po::command_line_parser(argc,
> argv).options(all).extra_parser(parse_no_options).run(), vm);
> 
> The extra parser is:
> 
> std::pair<std::string, std::string> parse_no_options
> (const std::string& s, const std::string name) {
>     if (s.find("--switch") != s.npos) {
>         if (s.substr (2, 3) == "no-")
>             return std::make_pair (s.substr (5), std::string("false"));
>         else
>             return std::make_pair (s.substr (2), std::string("true"));
>     }
> 
>     return std::make_pair (std::string(), std::string());
> }
> 
> This works fine for the command line.
> 
> I also need to implement this for the config file, but I do not know how
> to pass the extra parser to the parse_config_file. Is there a way?

I don't think so.

Sorry,
Volodya