使用 Boost 的 program_options 处理复杂的选项 [英] Handle complex options with Boost's program_options

问题描述

我有一个程序可以使用不同的多级模型生成图形.每个多级模型都包含生成一个较小的种子图(例如 50 个节点)，这些种子图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 包含它).

I have a program that generates graphs using different multi-level models. Each multi-level model consists of a generation of a smaller seed graph (say, 50 nodes) which can be created from several models (for example - for each possible edge, choose to include it with probability p).

在生成种子图后，使用另一组模型中的一个将图扩展为更大的图(比如 1000 个节点).

After the seed graph generation, the graph is expanded into a larger one (say 1000 nodes), using one of another set of models.

在两个阶段中的每一个阶段，每个模型都需要不同数量的参数.

In each of the two stages, each model require a different number of parameters.

我想让 program_options 根据模型的名称解析不同的可能参数.

I would like to be have program_options parse the different possible parameters, according to the names of the models.

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，同样分别具有 1 和 2 个参数.我希望能够执行以下操作:

For example, say I have two seed graphs models: SA, which has 1 parameters, and SB, which has two. Also for the expansion part, I have two models: A and B, again with 1 and 2 parameters, respectively. I would like to be able do something like:

./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.这可能吗?

and have the parameters parsed correctly. Is that even possible?

推荐答案

通过使用 自定义验证器 和 boost::program_options::value::multitoken，就可以达到想要的效果了:

By using a custom validator and boost::program_options::value::multitoken, you can achieve the desired result:

#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 << "
";
    if (seedModel.param1)
        std::cout << "Seed param1: " << *(seedModel.param1) << "
";
    if (seedModel.param2)
        std::cout << "Seed param2: " << *(seedModel.param2) << "
";

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

    return 0;
}

validate 函数可能需要更严格，但你懂的.

The validate function probably needs more rigor, but you get the idea.

这对我有用.

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