ceph/src/boost/libs/proto/include/boost/proto/context/default.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 /// \file default.hpp
   3 /// Definintion of default_context, a default evaluation context for
   4 /// proto::eval() that uses Boost.Typeof to deduce return types
   5 /// of the built-in operators.
   6 //
   7 //  Copyright 2008 Eric Niebler. Distributed under the Boost
   8 //  Software License, Version 1.0. (See accompanying file
   9 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  10
  11 #ifndef BOOST_PROTO_CONTEXT_DEFAULT_HPP_EAN_01_08_2007
  12 #define BOOST_PROTO_CONTEXT_DEFAULT_HPP_EAN_01_08_2007
  13
  14 #include <boost/config.hpp>
  15 #include <boost/preprocessor/arithmetic/add.hpp>
  16 #include <boost/preprocessor/arithmetic/sub.hpp>
  17 #include <boost/preprocessor/iteration/iterate.hpp>
  18 #include <boost/preprocessor/repetition/enum.hpp>
  19 #include <boost/preprocessor/repetition/enum_shifted.hpp>
  20 #include <boost/utility/result_of.hpp>
  21 #include <boost/type_traits/is_const.hpp>
  22 #include <boost/type_traits/is_function.hpp>
  23 #include <boost/type_traits/remove_reference.hpp>
  24 #include <boost/type_traits/is_member_pointer.hpp>
  25 #include <boost/type_traits/is_member_object_pointer.hpp>
  26 #include <boost/type_traits/is_member_function_pointer.hpp>
  27 #include <boost/proto/proto_fwd.hpp>
  28 #include <boost/proto/tags.hpp>
  29 #include <boost/proto/eval.hpp>
  30 #include <boost/proto/traits.hpp> // for proto::child_c()
  31 #include <boost/proto/detail/decltype.hpp>
  32
  33 namespace boost { namespace proto
  34 {
  35 /// INTERNAL ONLY
  36 ///
  37 #define UNREF(x) typename boost::remove_reference<x>::type
  38
  39     namespace context
  40     {
  41         template<
  42             typename Expr
  43           , typename Context
  44           , typename Tag        // = typename Expr::proto_tag
  45           , long Arity          // = Expr::proto_arity_c
  46         >
  47         struct default_eval
  48         {};
  49
  50         template<typename Expr, typename Context>
  51         struct default_eval<Expr, Context, tag::terminal, 0>
  52         {
  53             typedef
  54                 typename proto::result_of::value<Expr &>::type
  55             result_type;
  56
  57             result_type operator ()(Expr &expr, Context &) const
  58             {
  59                 return proto::value(expr);
  60             }
  61         };
  62
  63         /// INTERNAL ONLY
  64         ///
  65     #define BOOST_PROTO_UNARY_DEFAULT_EVAL(OP, TAG, MAKE)                                       \
  66         template<typename Expr, typename Context>                                               \
  67         struct default_eval<Expr, Context, TAG, 1>                                              \
  68         {                                                                                       \
  69         private:                                                                                \
  70             typedef typename proto::result_of::child_c<Expr, 0>::type e0;                       \
  71             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;               \
  72         public:                                                                                 \
  73             BOOST_PROTO_DECLTYPE_(OP proto::detail::MAKE<r0>(), result_type)                    \
  74             result_type operator ()(Expr &expr, Context &ctx) const                             \
  75             {                                                                                   \
  76                 return OP proto::eval(proto::child_c<0>(expr), ctx);                            \
  77             }                                                                                   \
  78         };                                                                                      \
  79         /**/
  80
  81         /// INTERNAL ONLY
  82         ///
  83     #define BOOST_PROTO_BINARY_DEFAULT_EVAL(OP, TAG, LMAKE, RMAKE)                              \
  84         template<typename Expr, typename Context>                                               \
  85         struct default_eval<Expr, Context, TAG, 2>                                              \
  86         {                                                                                       \
  87         private:                                                                                \
  88             typedef typename proto::result_of::child_c<Expr, 0>::type e0;                       \
  89             typedef typename proto::result_of::child_c<Expr, 1>::type e1;                       \
  90             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;               \
  91             typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;               \
  92         public:                                                                                 \
  93             BOOST_PROTO_DECLTYPE_(                                                              \
  94                 proto::detail::LMAKE<r0>() OP proto::detail::RMAKE<r1>()                        \
  95               , result_type                                                                     \
  96             )                                                                                   \
  97             result_type operator ()(Expr &expr, Context &ctx) const                             \
  98             {                                                                                   \
  99                 return proto::eval(                                                             \
 100                     proto::child_c<0>(expr), ctx) OP proto::eval(proto::child_c<1>(expr)        \
 101                   , ctx                                                                         \
 102                 );                                                                              \
 103             }                                                                                   \
 104         };                                                                                      \
 105         /**/
 106
 107         BOOST_PROTO_UNARY_DEFAULT_EVAL(+, proto::tag::unary_plus, make)
 108         BOOST_PROTO_UNARY_DEFAULT_EVAL(-, proto::tag::negate, make)
 109         BOOST_PROTO_UNARY_DEFAULT_EVAL(*, proto::tag::dereference, make)
 110         BOOST_PROTO_UNARY_DEFAULT_EVAL(~, proto::tag::complement, make)
 111         BOOST_PROTO_UNARY_DEFAULT_EVAL(&, proto::tag::address_of, make)
 112         BOOST_PROTO_UNARY_DEFAULT_EVAL(!, proto::tag::logical_not, make)
 113         BOOST_PROTO_UNARY_DEFAULT_EVAL(++, proto::tag::pre_inc, make_mutable)
 114         BOOST_PROTO_UNARY_DEFAULT_EVAL(--, proto::tag::pre_dec, make_mutable)
 115
 116         BOOST_PROTO_BINARY_DEFAULT_EVAL(<<, proto::tag::shift_left, make_mutable, make)
 117         BOOST_PROTO_BINARY_DEFAULT_EVAL(>>, proto::tag::shift_right, make_mutable, make)
 118         BOOST_PROTO_BINARY_DEFAULT_EVAL(*, proto::tag::multiplies, make, make)
 119         BOOST_PROTO_BINARY_DEFAULT_EVAL(/, proto::tag::divides, make, make)
 120         BOOST_PROTO_BINARY_DEFAULT_EVAL(%, proto::tag::modulus, make, make)
 121         BOOST_PROTO_BINARY_DEFAULT_EVAL(+, proto::tag::plus, make, make)
 122         BOOST_PROTO_BINARY_DEFAULT_EVAL(-, proto::tag::minus, make, make)
 123         BOOST_PROTO_BINARY_DEFAULT_EVAL(<, proto::tag::less, make, make)
 124         BOOST_PROTO_BINARY_DEFAULT_EVAL(>, proto::tag::greater, make, make)
 125         BOOST_PROTO_BINARY_DEFAULT_EVAL(<=, proto::tag::less_equal, make, make)
 126         BOOST_PROTO_BINARY_DEFAULT_EVAL(>=, proto::tag::greater_equal, make, make)
 127         BOOST_PROTO_BINARY_DEFAULT_EVAL(==, proto::tag::equal_to, make, make)
 128         BOOST_PROTO_BINARY_DEFAULT_EVAL(!=, proto::tag::not_equal_to, make, make)
 129         BOOST_PROTO_BINARY_DEFAULT_EVAL(||, proto::tag::logical_or, make, make)
 130         BOOST_PROTO_BINARY_DEFAULT_EVAL(&&, proto::tag::logical_and, make, make)
 131         BOOST_PROTO_BINARY_DEFAULT_EVAL(&, proto::tag::bitwise_and, make, make)
 132         BOOST_PROTO_BINARY_DEFAULT_EVAL(|, proto::tag::bitwise_or, make, make)
 133         BOOST_PROTO_BINARY_DEFAULT_EVAL(^, proto::tag::bitwise_xor, make, make)
 134
 135         BOOST_PROTO_BINARY_DEFAULT_EVAL(=, proto::tag::assign, make_mutable, make)
 136         BOOST_PROTO_BINARY_DEFAULT_EVAL(<<=, proto::tag::shift_left_assign, make_mutable, make)
 137         BOOST_PROTO_BINARY_DEFAULT_EVAL(>>=, proto::tag::shift_right_assign, make_mutable, make)
 138         BOOST_PROTO_BINARY_DEFAULT_EVAL(*=, proto::tag::multiplies_assign, make_mutable, make)
 139         BOOST_PROTO_BINARY_DEFAULT_EVAL(/=, proto::tag::divides_assign, make_mutable, make)
 140         BOOST_PROTO_BINARY_DEFAULT_EVAL(%=, proto::tag::modulus_assign, make_mutable, make)
 141         BOOST_PROTO_BINARY_DEFAULT_EVAL(+=, proto::tag::plus_assign, make_mutable, make)
 142         BOOST_PROTO_BINARY_DEFAULT_EVAL(-=, proto::tag::minus_assign, make_mutable, make)
 143         BOOST_PROTO_BINARY_DEFAULT_EVAL(&=, proto::tag::bitwise_and_assign, make_mutable, make)
 144         BOOST_PROTO_BINARY_DEFAULT_EVAL(|=, proto::tag::bitwise_or_assign, make_mutable, make)
 145         BOOST_PROTO_BINARY_DEFAULT_EVAL(^=, proto::tag::bitwise_xor_assign, make_mutable, make)
 146
 147     #undef BOOST_PROTO_UNARY_DEFAULT_EVAL
 148     #undef BOOST_PROTO_BINARY_DEFAULT_EVAL
 149
 150         /// INTERNAL ONLY
 151         template<typename Expr, typename Context>
 152         struct is_member_function_eval
 153           : is_member_function_pointer<
 154                 typename detail::uncvref<
 155                     typename proto::result_of::eval<
 156                         typename remove_reference<
 157                             typename proto::result_of::child_c<Expr, 1>::type
 158                         >::type
 159                       , Context
 160                     >::type
 161                 >::type
 162             >
 163         {};
 164
 165         /// INTERNAL ONLY
 166         template<typename Expr, typename Context, bool IsMemFunCall>
 167         struct memfun_eval
 168         {
 169         private:
 170             typedef typename result_of::child_c<Expr, 0>::type e0;
 171             typedef typename result_of::child_c<Expr, 1>::type e1;
 172             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
 173             typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
 174         public:
 175             typedef typename detail::mem_ptr_fun<r0, r1>::result_type result_type;
 176             result_type operator ()(Expr &expr, Context &ctx) const
 177             {
 178                 return detail::mem_ptr_fun<r0, r1>()(
 179                     proto::eval(proto::child_c<0>(expr), ctx)
 180                   , proto::eval(proto::child_c<1>(expr), ctx)
 181                 );
 182             }
 183         };
 184
 185         /// INTERNAL ONLY
 186         template<typename Expr, typename Context>
 187         struct memfun_eval<Expr, Context, true>
 188         {
 189         private:
 190             typedef typename result_of::child_c<Expr, 0>::type e0;
 191             typedef typename result_of::child_c<Expr, 1>::type e1;
 192             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
 193             typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
 194         public:
 195             typedef detail::memfun<r0, r1> result_type;
 196             result_type const operator ()(Expr &expr, Context &ctx) const
 197             {
 198                 return detail::memfun<r0, r1>(
 199                     proto::eval(proto::child_c<0>(expr), ctx)
 200                   , proto::eval(proto::child_c<1>(expr), ctx)
 201                 );
 202             }
 203         };
 204
 205         template<typename Expr, typename Context>
 206         struct default_eval<Expr, Context, tag::mem_ptr, 2>
 207           : memfun_eval<Expr, Context, is_member_function_eval<Expr, Context>::value>
 208         {};
 209
 210         // Handle post-increment specially.
 211         template<typename Expr, typename Context>
 212         struct default_eval<Expr, Context, proto::tag::post_inc, 1>
 213         {
 214         private:
 215             typedef typename proto::result_of::child_c<Expr, 0>::type e0;
 216             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
 217         public:
 218             BOOST_PROTO_DECLTYPE_(proto::detail::make_mutable<r0>() ++, result_type)
 219             result_type operator ()(Expr &expr, Context &ctx) const
 220             {
 221                 return proto::eval(proto::child_c<0>(expr), ctx) ++;
 222             }
 223         };
 224
 225         // Handle post-decrement specially.
 226         template<typename Expr, typename Context>
 227         struct default_eval<Expr, Context, proto::tag::post_dec, 1>
 228         {
 229         private:
 230             typedef typename proto::result_of::child_c<Expr, 0>::type e0;
 231             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
 232         public:
 233             BOOST_PROTO_DECLTYPE_(proto::detail::make_mutable<r0>() --, result_type)
 234             result_type operator ()(Expr &expr, Context &ctx) const
 235             {
 236                 return proto::eval(proto::child_c<0>(expr), ctx) --;
 237             }
 238         };
 239
 240         // Handle subscript specially.
 241         template<typename Expr, typename Context>
 242         struct default_eval<Expr, Context, proto::tag::subscript, 2>
 243         {
 244         private:
 245             typedef typename proto::result_of::child_c<Expr, 0>::type e0;
 246             typedef typename proto::result_of::child_c<Expr, 1>::type e1;
 247             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
 248             typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
 249         public:
 250             BOOST_PROTO_DECLTYPE_(proto::detail::make_subscriptable<r0>()[proto::detail::make<r1>()], result_type)
 251             result_type operator ()(Expr &expr, Context &ctx) const
 252             {
 253                 return proto::eval(proto::child_c<0>(expr), ctx)[proto::eval(proto::child_c<1>(expr), ctx)];
 254             }
 255         };
 256
 257         // Handle if_else_ specially.
 258         template<typename Expr, typename Context>
 259         struct default_eval<Expr, Context, proto::tag::if_else_, 3>
 260         {
 261         private:
 262             typedef typename proto::result_of::child_c<Expr, 0>::type e0;
 263             typedef typename proto::result_of::child_c<Expr, 1>::type e1;
 264             typedef typename proto::result_of::child_c<Expr, 2>::type e2;
 265             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
 266             typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
 267             typedef typename proto::result_of::eval<UNREF(e2), Context>::type r2;
 268         public:
 269             BOOST_PROTO_DECLTYPE_(
 270                 proto::detail::make<r0>()
 271               ? proto::detail::make<r1>()
 272               : proto::detail::make<r2>()
 273               , result_type
 274             )
 275             result_type operator ()(Expr &expr, Context &ctx) const
 276             {
 277                 return proto::eval(proto::child_c<0>(expr), ctx)
 278                       ? proto::eval(proto::child_c<1>(expr), ctx)
 279                       : proto::eval(proto::child_c<2>(expr), ctx);
 280             }
 281         };
 282
 283         // Handle comma specially.
 284         template<typename Expr, typename Context>
 285         struct default_eval<Expr, Context, proto::tag::comma, 2>
 286         {
 287         private:
 288             typedef typename proto::result_of::child_c<Expr, 0>::type e0;
 289             typedef typename proto::result_of::child_c<Expr, 1>::type e1;
 290             typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
 291             typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
 292         public:
 293             typedef typename proto::detail::comma_result<r0, r1>::type result_type;
 294             result_type operator ()(Expr &expr, Context &ctx) const
 295             {
 296                 return proto::eval(proto::child_c<0>(expr), ctx), proto::eval(proto::child_c<1>(expr), ctx);
 297             }
 298         };
 299
 300         // Handle function specially
 301         #define BOOST_PROTO_DEFAULT_EVAL_TYPE(Z, N, DATA)                                       \
 302             typename proto::result_of::eval<                                                    \
 303                 typename remove_reference<                                                      \
 304                     typename proto::result_of::child_c<DATA, N>::type                           \
 305                 >::type                                                                         \
 306               , Context                                                                         \
 307             >::type                                                                             \
 308             /**/
 309
 310         #define BOOST_PROTO_DEFAULT_EVAL(Z, N, DATA)                                            \
 311             proto::eval(proto::child_c<N>(DATA), context)                                       \
 312             /**/
 313
 314         template<typename Expr, typename Context>
 315         struct default_eval<Expr, Context, proto::tag::function, 1>
 316         {
 317             typedef
 318                 typename proto::detail::result_of_fixup<
 319                     BOOST_PROTO_DEFAULT_EVAL_TYPE(~, 0, Expr)
 320                 >::type
 321             function_type;
 322
 323             typedef
 324                 typename BOOST_PROTO_RESULT_OF<function_type()>::type
 325             result_type;
 326
 327             result_type operator ()(Expr &expr, Context &context) const
 328             {
 329                 return BOOST_PROTO_DEFAULT_EVAL(~, 0, expr)();
 330             }
 331         };
 332
 333         template<typename Expr, typename Context>
 334         struct default_eval<Expr, Context, proto::tag::function, 2>
 335         {
 336             typedef
 337                 typename proto::detail::result_of_fixup<
 338                     BOOST_PROTO_DEFAULT_EVAL_TYPE(~, 0, Expr)
 339                 >::type
 340             function_type;
 341
 342             typedef
 343                 typename detail::result_of_<
 344                     function_type(BOOST_PROTO_DEFAULT_EVAL_TYPE(~, 1, Expr))
 345                 >::type
 346             result_type;
 347
 348             result_type operator ()(Expr &expr, Context &context) const
 349             {
 350                 return this->invoke(
 351                     expr
 352                   , context
 353                   , is_member_function_pointer<function_type>()
 354                   , is_member_object_pointer<function_type>()
 355                 );
 356             }
 357
 358         private:
 359             result_type invoke(Expr &expr, Context &context, mpl::false_, mpl::false_) const
 360             {
 361                 return BOOST_PROTO_DEFAULT_EVAL(~, 0, expr)(BOOST_PROTO_DEFAULT_EVAL(~, 1, expr));
 362             }
 363
 364             result_type invoke(Expr &expr, Context &context, mpl::true_, mpl::false_) const
 365             {
 366                 BOOST_PROTO_USE_GET_POINTER();
 367                 typedef typename detail::class_member_traits<function_type>::class_type class_type;
 368                 return (
 369                     BOOST_PROTO_GET_POINTER(class_type, (BOOST_PROTO_DEFAULT_EVAL(~, 1, expr))) ->*
 370                     BOOST_PROTO_DEFAULT_EVAL(~, 0, expr)
 371                 )();
 372             }
 373
 374             result_type invoke(Expr &expr, Context &context, mpl::false_, mpl::true_) const
 375             {
 376                 BOOST_PROTO_USE_GET_POINTER();
 377                 typedef typename detail::class_member_traits<function_type>::class_type class_type;
 378                 return (
 379                     BOOST_PROTO_GET_POINTER(class_type, (BOOST_PROTO_DEFAULT_EVAL(~, 1, expr))) ->*
 380                     BOOST_PROTO_DEFAULT_EVAL(~, 0, expr)
 381                 );
 382             }
 383         };
 384
 385         // Additional specialization are generated by the preprocessor
 386         #include <boost/proto/context/detail/default_eval.hpp>
 387
 388         #undef BOOST_PROTO_DEFAULT_EVAL_TYPE
 389         #undef BOOST_PROTO_DEFAULT_EVAL
 390
 391         /// default_context
 392         ///
 393         struct default_context
 394         {
 395             /// default_context::eval
 396             ///
 397             template<typename Expr, typename ThisContext = default_context const>
 398             struct eval
 399               : default_eval<Expr, ThisContext>
 400             {};
 401         };
 402
 403     } // namespace context
 404
 405 }} // namespace boost::proto
 406
 407 #undef UNREF
 408
 409 #endif