refactor: make talon's choice of result message easier to read in the code as per Richard's suggestion.
// Copyright David Abrahams 2005. 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)
#ifndef BOOST_DETAIL_IS_XXX_DWA20051011_HPP
# define BOOST_DETAIL_IS_XXX_DWA20051011_HPP
# include <boost/config.hpp>
# include <boost/mpl/bool.hpp>
# include <boost/preprocessor/enum_params.hpp>
# if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
# include <boost/type_traits/is_reference.hpp>
# include <boost/type_traits/add_reference.hpp>
# define BOOST_DETAIL_IS_XXX_DEF(name, qualified_name, nargs) \
template <class X_> \
struct is_##name \
{ \
typedef char yes; \
typedef char (&no)[2]; \
\
static typename add_reference<X_>::type dummy; \
\
struct helpers \
{ \
template < BOOST_PP_ENUM_PARAMS_Z(1, nargs, class U) > \
static yes test( \
qualified_name< BOOST_PP_ENUM_PARAMS_Z(1, nargs, U) >&, int \
); \
\
template <class U> \
static no test(U&, ...); \
}; \
\
BOOST_STATIC_CONSTANT( \
bool, value \
= !is_reference<X_>::value \
& (sizeof(helpers::test(dummy, 0)) == sizeof(yes))); \
\
typedef mpl::bool_<value> type; \
};
# else
# define BOOST_DETAIL_IS_XXX_DEF(name, qualified_name, nargs) \
template <class T> \
struct is_##name : mpl::false_ \
{ \
}; \
\
template < BOOST_PP_ENUM_PARAMS_Z(1, nargs, class T) > \
struct is_##name< \
qualified_name< BOOST_PP_ENUM_PARAMS_Z(1, nargs, T) > \
> \
: mpl::true_ \
{ \
};
# endif
#endif // BOOST_DETAIL_IS_XXX_DWA20051011_HPP