boost/boost/python/detail/is_xxx.hpp

   1 // Copyright David Abrahams 2003. Permission to copy, use,
   2 // modify, sell and distribute this software is granted provided this
   3 // copyright notice appears in all copies. This software is provided
   4 // "as is" without express or implied warranty, and with no claim as
   5 // to its suitability for any purpose.
   6 #ifndef IS_XXX_DWA2003224_HPP
   7 # define IS_XXX_DWA2003224_HPP
   8
   9 # include <boost/config.hpp>
  10 # include <boost/mpl/bool.hpp>
  11 # include <boost/preprocessor/enum_params.hpp>
  12
  13 # if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
  14 # include <boost/type_traits/is_reference.hpp>
  15 # include <boost/type_traits/add_reference.hpp>
  16
  17 #  define BOOST_PYTHON_IS_XXX_DEF(name, qualified_name, nargs)          \
  18 template <class X_>                                                     \
  19 struct is_##name                                                        \
  20 {                                                                       \
  21     typedef char yes;                                                   \
  22     typedef char (&no)[2];                                              \
  23                                                                         \
  24     static typename add_reference<X_>::type dummy;                      \
  25                                                                         \
  26     struct helpers                                                      \
  27     {                                                                   \
  28         template < BOOST_PP_ENUM_PARAMS_Z(1, nargs, class U) >          \
  29         static yes test(                                                \
  30            qualified_name< BOOST_PP_ENUM_PARAMS_Z(1, nargs, U) >&, int  \
  31         );                                                              \
  32                                                                         \
  33         template <class U>                                              \
  34         static no test(U&, ...);                                        \
  35     };                                                                  \
  36                                                                         \
  37     BOOST_STATIC_CONSTANT(                                              \
  38         bool, value                                                     \
  39         = !is_reference<X_>::value                                      \
  40         & (sizeof(helpers::test(dummy, 0)) == sizeof(yes)));            \
  41                                                                         \
  42     typedef mpl::bool_<value> type;                                     \
  43 };
  44
  45 # else
  46
  47 #  define BOOST_PYTHON_IS_XXX_DEF(name, qualified_name, nargs)  \
  48 template <class T>                                              \
  49 struct is_##name : mpl::false_                                  \
  50 {                                                               \
  51 };                                                              \
  52                                                                 \
  53 template < BOOST_PP_ENUM_PARAMS_Z(1, nargs, class T) >          \
  54 struct is_##name<                                               \
  55    qualified_name< BOOST_PP_ENUM_PARAMS_Z(1, nargs, T) >        \
  56 >                                                               \
  57    : mpl::true_                                                 \
  58 {                                                               \
  59 };
  60
  61 # endif
  62
  63 #endif // IS_XXX_DWA2003224_HPP