basic C++11 string formatting

format.cc

#include <sstream>
#include <iostream>

struct formatter {
    std::string format;

    formatter(const std::string &format_)
        : format(format_) {}
    formatter(const formatter &other) = delete;
    formatter(formatter &&other)
        : format(std::move(other.format)) {}

    template <typename Iter, typename Arg, typename ...Args>
        void vformat(std::stringstream &ss, Iter &i, Arg arg) {
            while (i < std::end(format)) {
                switch (*i) {
                    case '{':
                        ++i; ++i; // eat the '}'
                        ss << arg;
                        break;
                    default:
                        ss << *i;
                        ++i;
                        break;
                }
            }
        }


    template <typename Iter, typename Arg, typename ...Args>
        void vformat(std::stringstream &ss, Iter &i, Arg arg, Args ...args) {
            while (i < std::end(format)) {
                switch (*i) {
                    case '{':
                        ++i; ++i; // eat the '}'
                        ss << arg;
                        vformat(ss, i, args...);
                        return;
                    default:
                        ss << *i;
                        ++i;
                        break;
                }
            }
        }

    template <typename ...Args>
        std::string operator()(Args ...args) {
            std::stringstream ss;
            auto i = std::begin(format);
            vformat(ss, i, args...);
            return ss.str();
        }
};

formatter operator"" _fmt(const char *p, size_t n) {
    return std::move(formatter(std::string(p, n)));
}

int main() {
    using namespace std;
    cout << "welcome {} {} = {}"_fmt("foo", "bar", 1.3) << endl;
}

$ g++-4.7 -Wall -ggdb -std=c++11 format.cc
$ ./a.out
welcome foo bar = 1.3