【转】bind简单示例

bind简单示例代码

namespace

{

    class placeholder_ {};

    placeholder_ __1;

}

template <typename R, typename T, typename Arg>

class simple_bind_t

{

private:

    typedef R (T::*F)(Arg);

    F f_;

    T* t_;

    Arg& a_;

public:

    simple_bind_t(F f, T* t, Arg &a)

        : f_(f), t_(t), a_(a)

    {}

    R operator()()

    {

        return (t_->*f_)(a_);

    }

};

template <typename R, typename T, typename Arg>

class simple_bind_t2

{

private:

    typedef R (T::*F)(Arg);

    F f_;

    T* t_;

public:

    simple_bind_t2(F f, T* t)

        : f_(f), t_(t)

    {}

    R operator()(Arg& a)

    {

        return (t_->*f_)(a);

    }

};

template <typename R, typename T, typename Arg>

simple_bind_t<R, T, Arg> simple_bind(R (T::*f)(Arg), T* t, Arg& a)

{

    return simple_bind_t<R, T, Arg>(f, t, a);

}

template <typename R, typename T, typename Arg>

simple_bind_t2<R, T, Arg> simple_bind(R (T::*f)(Arg), T* t, placeholder_& a)

{

    return simple_bind_t2<R, T, Arg>(f, t);

}

class bind_test

{

public:

    void print_string(const std::string str)

    {

        printf("%s", str.c_str());

    }

};

void test()

{

    bind_test t;

    std::string h = "hehe\n";

    simple_bind(&bind_test::print_string, &t, h)();

    simple_bind(&bind_test::print_string, &t, __1)(h);

    boost::function<void (const std::string)> f;

    f = simple_bind(&bind_test::print_string, &t, __1);

    f(h);

}

运行结果

test函数返回结果应该是:

hehe

hehe

hehe