105 lines
4.4 KiB
Plaintext
105 lines
4.4 KiB
Plaintext
// 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 "boost/config.hpp" // for BOOST_STATIC_CONSTANT
|
|
#include "boost/type_traits/conversion_traits.hpp" // for is_convertible
|
|
#include "boost/preprocessor/enum_shifted_params.hpp"
|
|
#include "boost/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 boost::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 boost {
|
|
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 ::boost::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
|
|
|
|
|
|
|
|
|
|
|