Unary function pointers in C++ for Dan W

fn_ptrs.cc

#include <iostream>
#include <map>
#include <functional>

class some_arg_t {
    public:
        some_arg_t(const char *name) : name_(name) {};

        const char *name() const { return name_.c_str(); }

    private:
        std::string name_;
};

typedef std::pointer_to_unary_function<const some_arg_t &, int> fn_t;

typedef std::map<std::string, fn_t > fn_map_t;

int
do_a (const some_arg_t &arg)
{
    std::cout << "a: " << arg.name() << std::endl;
    return 0;
}

int
do_b (const some_arg_t &arg)
{
    std::cout << "b: " << arg.name() << std::endl;
    return 0;
}

int
main (int argc, char **argv)
{
    fn_map_t f;
    some_arg_t arg("hello");

    f["a"] = std::ptr_fun (do_a);
    f["b"] = std::ptr_fun (do_b);

    const fn_t &fn = f["a"];
    fn (arg);

    return 0;
}