String Arguments to Multi-File Subcommand

[tornupnegatives]

I am trying to build a CLI application with multiple subcommands, where each subcommmand is defined in its own file. Currently, my subcommand class looks something like:

class EncoderCommand : public CLI::App {
 public:
    explicit EncoderCommand(CLI::App& app);
    int run();

 private:
    bool validateArgs();
    std::vector<Frame> encodeAudioAsFrames();

    std::string input_path_;
    std::string output_path_;
};

In the constructor, I attach the subcommand to its parent and then configure arguments, but I am running into an issue binding the string arguments due to them lacking the stream operator. See the function snipped and error below.

EncoderCommand::EncoderCommand(CLI::App& app) {
    auto input_path_ptr = std::make_shared<std::string>(input_path_);
    auto output_path_ptr = std::make_shared<std::string>(output_path_);

    auto* sub =
        app.add_subcommand("encode", "Converts audio file to bitstream");

    add_option("-i,--input,input", input_path_ptr, "Path to audio file")
        ->required()
        ->check(CLI::ExistingFile);

    add_option("-o,--output,output", output_path_ptr, "Path to output file")
        ->required();

    sub->callback([this]() { this->run(); });
}

In file included from /Users/joe/Code/TMS-Express/src/ui/cli/EncoderCommand.cpp:3:
In file included from /Users/joe/Code/TMS-Express/src/ui/cli/EncoderCommand.hpp:9:
In file included from /Users/joe/Code/TMS-Express/build/_deps/cli11-src/include/CLI/CLI.hpp:24:
/Users/joe/Code/TMS-Express/build/_deps/cli11-src/include/CLI/TypeTools.hpp:1251:5: error: static assertion failed due to requirement 'is_istreamable<std::shared_ptr<std::string>, std::istringstream>::value': option object type must have a lexical cast overload or streaming input operator(>>) defined, if it is convertible from another type use the add_option<T, XC>(...) with XC being the known type
    static_assert(is_istreamable<T>::value,
    ^             ~~~~~~~~~~~~~~~~~~~~~~~~
/Users/joe/Code/TMS-Express/build/_deps/cli11-src/include/CLI/TypeTools.hpp:1286:12: note: in instantiation of function template specialization 'CLI::detail::lexical_cast<std::shared_ptr<std::string>, (CLI::detail::enabler)0>' requested here
    return lexical_cast(input, output);
           ^
/Users/joe/Code/TMS-Express/build/_deps/cli11-src/include/CLI/TypeTools.hpp:1370:12: note: in instantiation of function template specialization 'CLI::detail::lexical_assign<std::shared_ptr<std::string>, std::shared_ptr<std::string>, (CLI::detail::enabler)0>' requested here
    return lexical_assign<AssignTo, ConvertTo>(strings[0], output);
           ^
/Users/joe/Code/TMS-Express/build/_deps/cli11-src/include/CLI/App.hpp:531:28: note: in instantiation of function template specialization 'CLI::detail::lexical_conversion<std::shared_ptr<std::string>, std::shared_ptr<std::string>, (CLI::detail::enabler)0>' requested here
            return detail::lexical_conversion<AssignTo, ConvertTo>(res, variable);
                           ^
/Users/joe/Code/TMS-Express/src/ui/cli/EncoderCommand.cpp:110:5: note: in instantiation of function template specialization 'CLI::App::add_option<std::shared_ptr<std::string>, std::shared_ptr<std::string>, (CLI::detail::enabler)0>' requested here
    add_option("-i,--input,input", input_path_ptr, "Path to audio file")
    ^
1 error generated.

Can anyone suggest a better way to handle this case?

[phlptp]

When I want to define a subcommand or even option group in a separate file I usually just have a function call that generates a std::shared_ptr<CLI::App> That can be added directly to a main app, or added to directly.

There are a number of issues with the way you are doing it right now.

EncoderCommand::EncoderCommand(CLI::App& app) {
    auto input_path_ptr = std::make_shared<std::string>(input_path_); //This is a local variable it be destroyed when the method returns
    auto output_path_ptr = std::make_shared<std::string>(output_path_);  //really you probably don't want the shared_ptr here, just use input_path_ directly in the add_option.  

    auto* sub =
        app.add_subcommand("encode", "Converts audio file to bitstream");

    add_option("-i,--input,input", input_path_ptr, "Path to audio file")
        ->required()
        ->check(CLI::ExistingFile); // CLI11 doesn't know what to do with a shared_ptr directly this should be `*input_path_ptr`  (ignoring lifetime issues here)

    add_option("-o,--output,output", output_path_ptr, "Path to output file")
        ->required();

    sub->callback([this]() { this->run(); });
}

[tornupnegatives]

Thanks for getting back to me! The issue with not de-referencing the pointer makes total sense... I will provide some updates later in the week when I get a chance to work on this.