bind_as_compose.cpp

#include <boost/config.hpp>

#if defined(BOOST_MSVC)
#pragma warning(disable: 4786)  // identifier truncated in debug info
#pragma warning(disable: 4710)  // function not inlined
#pragma warning(disable: 4711)  // function selected for automatic inline expansion
#pragma warning(disable: 4514)  // unreferenced inline removed
#endif

//
//  bind_as_compose.cpp - function composition using bind.hpp
//
//  Version 1.00.0001 (2001-08-30)
//
//  Copyright (c) 2001 Peter Dimov and Multi Media Ltd.
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//

#include <boost/bind/bind.hpp>
#include <iostream>
#include <string>

using namespace boost::placeholders;

std::string f(std::string const & x)
{
    return "f(" + x + ")";
}

std::string g(std::string const & x)
{
    return "g(" + x + ")";
}

std::string h(std::string const & x, std::string const & y)
{
    return "h(" + x + ", " + y + ")";
}

std::string k()
{
    return "k()";
}

template<class F> void test(F f)
{
    std::cout << f("x", "y") << '\n';
}

int main()
{
    using namespace boost;

    // compose_f_gx

    test( bind(f, bind(g, _1)) );

    // compose_f_hxy

    test( bind(f, bind(h, _1, _2)) );

    // compose_h_fx_gx

    test( bind(h, bind(f, _1), bind(g, _1)) );

    // compose_h_fx_gy

    test( bind(h, bind(f, _1), bind(g, _2)) );

    // compose_f_k

    test( bind(f, bind(k)) );

    return 0;
}