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// Boost Lambda Library - is_instance_of.hpp ---------------------
// Copyright (C) 2001 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
//
// 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)
//
// For more information, see www.boost.org
// ---------------------------------------------------------------
#ifndef BOOST_LAMBDA_IS_INSTANCE_OF
#define BOOST_LAMBDA_IS_INSTANCE_OF
#include "ndnboost/config.hpp" // for BOOST_STATIC_CONSTANT
#include "ndnboost/type_traits/conversion_traits.hpp" // for is_convertible
#include "ndnboost/preprocessor/enum_shifted_params.hpp"
#include "ndnboost/preprocessor/repeat_2nd.hpp"
// is_instance_of --------------------------------
//
// is_instance_of_n<A, B>::value is true, if type A is
// an instantiation of a template B, or A derives from an instantiation
// of template B
//
// n is the number of template arguments for B
//
// Example:
// is_instance_of_2<std::istream, basic_stream>::value == true
// The original implementation was somewhat different, with different versions
// for different compilers. However, there was still a problem
// with gcc.3.0.2 and 3.0.3 compilers, which didn't think regard
// is_instance_of_N<...>::value was a constant.
// John Maddock suggested the way around this problem by building
// is_instance_of templates using ndnboost::is_convertible.
// Now we only have one version of is_instance_of templates, which delagate
// all the nasty compiler tricks to is_convertible.
#define BOOST_LAMBDA_CLASS(z, N,A) BOOST_PP_COMMA_IF(N) class
#define BOOST_LAMBDA_CLASS_ARG(z, N,A) BOOST_PP_COMMA_IF(N) class A##N
#define BOOST_LAMBDA_ARG(z, N,A) BOOST_PP_COMMA_IF(N) A##N
#define BOOST_LAMBDA_CLASS_LIST(n, NAME) BOOST_PP_REPEAT(n, BOOST_LAMBDA_CLASS, NAME)
#define BOOST_LAMBDA_CLASS_ARG_LIST(n, NAME) BOOST_PP_REPEAT(n, BOOST_LAMBDA_CLASS_ARG, NAME)
#define BOOST_LAMBDA_ARG_LIST(n, NAME) BOOST_PP_REPEAT(n, BOOST_LAMBDA_ARG, NAME)
namespace ndnboost {
namespace lambda {
#define BOOST_LAMBDA_IS_INSTANCE_OF_TEMPLATE(INDEX) \
\
namespace detail { \
\
template <template<BOOST_LAMBDA_CLASS_LIST(INDEX,T)> class F> \
struct BOOST_PP_CAT(conversion_tester_,INDEX) { \
template<BOOST_LAMBDA_CLASS_ARG_LIST(INDEX,A)> \
BOOST_PP_CAT(conversion_tester_,INDEX) \
(const F<BOOST_LAMBDA_ARG_LIST(INDEX,A)>&); \
}; \
\
} /* end detail */ \
\
template <class From, template <BOOST_LAMBDA_CLASS_LIST(INDEX,T)> class To> \
struct BOOST_PP_CAT(is_instance_of_,INDEX) \
{ \
private: \
typedef ::ndnboost::is_convertible< \
From, \
BOOST_PP_CAT(detail::conversion_tester_,INDEX)<To> \
> helper_type; \
\
public: \
BOOST_STATIC_CONSTANT(bool, value = helper_type::value); \
};
#define BOOST_LAMBDA_HELPER(z, N, A) BOOST_LAMBDA_IS_INSTANCE_OF_TEMPLATE( BOOST_PP_INC(N) )
// Generate the traits for 1-4 argument templates
BOOST_PP_REPEAT_2ND(4,BOOST_LAMBDA_HELPER,FOO)
#undef BOOST_LAMBDA_HELPER
#undef BOOST_LAMBDA_IS_INSTANCE_OF_TEMPLATE
#undef BOOST_LAMBDA_CLASS
#undef BOOST_LAMBDA_ARG
#undef BOOST_LAMBDA_CLASS_ARG
#undef BOOST_LAMBDA_CLASS_LIST
#undef BOOST_LAMBDA_ARG_LIST
#undef BOOST_LAMBDA_CLASS_ARG_LIST
} // lambda
} // boost
#endif