lagoon/example/std_range_04.cpp

This example shows the usage of the namespace reflection functions and std range adaptor together with algorithms from the standard library.

Copyright 2008-2010 Matus Chochlik. 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 <mirror/mirror.hpp>
#include <lagoon/lagoon.hpp>
#include <lagoon/range/std_range.hpp>
#include <lagoon/range/only_if.hpp>
#include <lagoon/range/transform.hpp>

#include <iostream>
#include <algorithm>

int main(void)
{
    using namespace lagoon;
    typedef shared<meta_named_scoped_object> shared_mnso;
    typedef shared<meta_type> shared_mt;
    // get the members of the global scope, extract only types
    // and adapt the range to have the standard begin()/end()
    // member functions returning standard conforming iterators
    auto mosr = make_std_range(
        transform(
            only_if(
                reflected_global_scope()->members(),
                [](const shared_mnso& member)
                {
                    return member->is_type();
                }
            ),
            [](const shared_mnso& member)
            {
                return member.as<meta_type>();
            }
        )
    );
    // now use the standard count_if algorithm with a lambda
    // unary predicate counting only types whose size is 4 bytes
    std::cout << std::count_if(
        mosr.begin(),
        mosr.end(),
        [](const shared_mt& metatype) -> bool
        {
            return metatype->size_of() == 4;
        }
    ) << std::endl;
    return 0;
}

/* Example of output:
6
*/