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type_erasure/example/compose.cpp
2012-07-20 23:46:27 +00:00

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// Boost.TypeErasure library
//
// Copyright 2011 Steven Watanabe
//
// 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)
//
// $Id$
#include <boost/type_erasure/builtin.hpp>
#include <boost/type_erasure/operators.hpp>
#include <boost/mpl/vector.hpp>
namespace mpl = boost::mpl;
using namespace boost::type_erasure;
//[compose1
/*`
The basic concepts, like __copy_constructible and
__incrementable, are useful, but dealing with many
such concepts quickly gets cumbersome. Fortunately,
the library allows us to combine several concepts into
a single concept using an MPL sequence.
*/
template<class T = _self>
struct arithmetic :
mpl::vector<
copy_constructible<T>,
addable<T>,
subtractable<T>,
multipliable<T>,
dividable<T>,
equality_comparable<T>,
less_than_comparable<T>
>
{};
/*`
Now, `arithmetic` can be used just like any
of the base concepts. We can even specialize
__concept_interface for it if we want to
add to or override the behavior of the base
concepts.
*/
//]
//[compose
//` (For the source of the examples in this section see
//` [@boost:/libs/type_erasure/example/compose.cpp compose.cpp])
//` [compose1]
//]