使用Boost的program_options处理复杂的选项

Question

我有一个程序,使用不同的多级模型生成图形.每个多级模型由一代较小的种子图(例如,50个节点)组成,可以从多个模型创建(例如 - 对于每个可能的边,选择以概率p包括它).

在种子图生成之后,使用另一组模型之一将图扩展为更大的图(例如1000个节点).

在两个阶段的每个阶段中,每个模型需要不同数量的参数.

我想让program_options根据模型的名称解析不同的可能参数.

例如,假设我有两个种子图模型:SA,有1个参数,SB,有两个.同样对于扩展部分,我有两个模型:A和B,分别有1和2个参数.我希望能够做到这样的事情:

./graph_generator --seed=SA 0.1 --expansion=A 0.2
./graph_generator --seed=SB 0.1 3 --expansion=A 0.2
./graph_generator --seed=SA 0.1 --expansion=B 10 20
./graph_generator --seed=SB 0.1 3 --expansion=B 10 20

并正确解析参数.这甚至可能吗？

Answer 1

通过使用自定义验证器和boost :: program_options :: value :: multitoken,您可以获得所需的结果:

#include <iostream>
#include <boost/lexical_cast.hpp>
#include <boost/optional.hpp>
#include <boost/program_options.hpp>

// Holds parameters for seed/expansion model
struct Model
{
    std::string type;
    boost::optional<float> param1;
    boost::optional<float> param2;
};

// Called by program_options to parse a set of Model arguments
void validate(boost::any& v, const std::vector<std::string>& values,
              Model*, int)
{
    Model model;
    // Extract tokens from values string vector and populate Model struct.
    if (values.size() == 0)
    {
        throw boost::program_options::validation_error(
            "Invalid model specification");
    }
    model.type = values.at(0); // Should validate for A/B
    if (values.size() >= 2)
        model.param1 = boost::lexical_cast<float>(values.at(1));
    if (values.size() >= 3)
        model.param2 = boost::lexical_cast<float>(values.at(2));

    v = model;
}

int main(int argc, char* argv[])
{
    Model seedModel, expansionModel;

    namespace po = boost::program_options;
    po::options_description options("Generic options");
    options.add_options()
        ("seed",
             po::value<Model>(&seedModel)->multitoken(),
             "seed graph model")
        ("expansion",
             po::value<Model>(&expansionModel)->multitoken(),
             "expansion model")
        ;

    po::variables_map vm;
    po::store(po::parse_command_line(argc, argv, options), vm);
    po::notify(vm);

    std::cout << "Seed type: " << seedModel.type << "\n";
    if (seedModel.param1)
        std::cout << "Seed param1: " << *(seedModel.param1) << "\n";
    if (seedModel.param2)
        std::cout << "Seed param2: " << *(seedModel.param2) << "\n";

    std::cout << "Expansion type: " << expansionModel.type << "\n";
    if (expansionModel.param1)
        std::cout << "Expansion param1: " << *(expansionModel.param1) << "\n";
    if (expansionModel.param2)
        std::cout << "Expansion param2: " << *(expansionModel.param2) << "\n";

    return 0;
}

该validate功能可能需要更严格,但你明白了.

这编译并为我工作.