charmed examples

example.cpp

#include <iostream>
#include <string>
#include <boost/foreach.hpp>
#include <charmed/charmed.hpp>

// the attribute
struct operation_attribute
{
    operation_attribute(std::string const& name_, std::string const& help_)
        : name(name_), help(help_)
    {}

    std::string name;
    std::string help;
};

// tell charmed to index operation_attributes by their name
namespace charmed
{
    template <>
    struct index_specifier_of<operation_attribute>
    {
        typedef boost::multi_index::indexed_by<
            boost::multi_index::sequenced,
            boost::multi_index::ordered_unique<
                boost::multi_index::member<
                    operation_attribute,
                    std::string,
                    &operation_attribute::name
                >
            >
        > type;
    };
}

// the operations
typedef void (operation_type)(int, char**);

void operation1(int argc, char ** argv)
{
    std::cout << "IN operation1" << std::endl;
}

CHARMED_TAG_FUNCTION(
    &operation1, operation_attribute("operation1", "This is the first operation."));

void operation2(int argc, char ** argv)
{
    std::cout << "IN operation2" << std::endl;
}

CHARMED_TAG_FUNCTION(
    &operation2, operation_attribute("operation2", "This is the second operation."));

void help(int argc, char ** argv)
{
    std::cout << "Available operations are:\n" << std::endl;
    BOOST_FOREACH(operation_attribute const& oa,
                  charmed::all_attributes<operation_attribute, 1>())
    {
        std::cout << oa.name << " - " << oa.help << std::endl;
    }
}

CHARMED_TAG_FUNCTION(&help, operation_attribute("help", "Displays this message."));

int main(int argc, char ** argv)
{
    // for brevity, assume the args are correct
    std::string op_name(argv[1]);

    // find the op by name & invoke it
    operation_attribute const* oa =
        charmed::find_attribute<operation_attribute, 1>(op_name);

    if (!oa)
    {
        std::cout << "Don't know what the '" << op_name << "' operation is..."
                  << std::endl;
        return EXIT_FAILURE;
    }

    charmed::tagged_type_of<operation_type>(*oa)(argc, argv);

    return EXIT_SUCCESS;
}