Class CommandLine

tests/catch.h:4224–4606

    template<typename ConfigT>
    class CommandLine {

        struct Arg : CommonArgProperties<ConfigT>, OptionArgProperties, PositionalArgProperties {
            Arg() {}
            Arg( Detail::BoundArgFunction<ConfigT> const& _boundField ) : CommonArgProperties<ConfigT>( _boundField ) {}

            using CommonArgProperties<ConfigT>::placeholder; // !TBD

            std::string dbgName() const {
                if( !longName.empty() )
                    return "--" + longName;
                if( !shortNames.empty() )
                    return "-" + shortNames[0];
                return "positional args";
            }
            std::string commands() const {
                std::ostringstream oss;
                bool first = true;
                std::vector<std::string>::const_iterator it = shortNames.begin(), itEnd = shortNames.end();
                for(; it != itEnd; ++it ) {
                    if( first )
                        first = false;
                    else
                        oss << ", ";
                    oss << "-" << *it;
                }
                if( !longName.empty() ) {
                    if( !first )
                        oss << ", ";
                    oss << "--" << longName;
                }
                if( !placeholder.empty() )
                    oss << " <" << placeholder << ">";
                return oss.str();
            }
        };

        typedef CLARA_AUTO_PTR( Arg ) ArgAutoPtr;

        friend void addOptName( Arg& arg, std::string const& optName )
        {
            if( optName.empty() )
                return;
            if( Detail::startsWith( optName, "--" ) ) {
                if( !arg.longName.empty() )
                    throw std::logic_error( "Only one long opt may be specified. '"
                        + arg.longName
                        + "' already specified, now attempting to add '"
                        + optName + "'" );
                arg.longName = optName.substr( 2 );
            }
            else if( Detail::startsWith( optName, "-" ) )
                arg.shortNames.push_back( optName.substr( 1 ) );
            else
                throw std::logic_error( "option must begin with - or --. Option was: '" + optName + "'" );
        }
        friend void setPositionalArg( Arg& arg, int position )
        {