boost/xpressive/proto/context/default.hpp
#ifndef BOOST_PP_IS_ITERATING
///////////////////////////////////////////////////////////////////////////////
/// \file default.hpp
/// Definintion of default_context, a default evaluation context for
/// proto::eval() that uses Boost.Typeof to deduce return types
/// of the built-in operators.
//
// Copyright 2008 Eric Niebler. 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_PROTO_CONTEXT_DEFAULT_HPP_EAN_01_08_2007
#define BOOST_PROTO_CONTEXT_DEFAULT_HPP_EAN_01_08_2007
#include <boost/xpressive/proto/detail/prefix.hpp> // must be first include
#include <boost/config.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/repetition/enum_shifted.hpp>
#include <boost/preprocessor/selection/max.hpp>
#include <boost/mpl/if.hpp>
#include <boost/typeof/typeof.hpp>
#include <boost/utility/result_of.hpp>
#include <boost/type_traits/is_const.hpp>
#include <boost/type_traits/is_function.hpp>
#include <boost/type_traits/remove_reference.hpp>
#include <boost/xpressive/proto/proto_fwd.hpp>
#include <boost/xpressive/proto/tags.hpp>
#include <boost/xpressive/proto/eval.hpp>
#include <boost/xpressive/proto/traits.hpp> // for proto::arg_c()
#include <boost/xpressive/proto/detail/suffix.hpp> // must be last include
namespace boost { namespace proto
{
// If we're generating doxygen documentation, hide all the nasty
// Boost.Typeof gunk.
#ifndef BOOST_PROTO_DOXYGEN_INVOKED
#define BOOST_PROTO_DECLTYPE_NESTED_TYPEDEF_TPL_(Nested, Expr)\
BOOST_TYPEOF_NESTED_TYPEDEF_TPL(BOOST_PP_CAT(nested_and_hidden_, Nested), Expr)\
static int const sz = sizeof(proto::detail::check_reference(Expr));\
struct Nested\
: mpl::if_c<\
1==sz\
, typename BOOST_PP_CAT(nested_and_hidden_, Nested)::type &\
, typename BOOST_PP_CAT(nested_and_hidden_, Nested)::type\
>\
{};
#define BOOST_PROTO_DECLTYPE_(Expr, Type)\
BOOST_PROTO_DECLTYPE_NESTED_TYPEDEF_TPL_(BOOST_PP_CAT(nested_, Type), (Expr))\
typedef typename BOOST_PP_CAT(nested_, Type)::type Type;
#else
/// INTERNAL ONLY
///
#define BOOST_PROTO_DECLTYPE_NESTED_TYPEDEF_TPL_(Nested, Expr)
/// INTERNAL ONLY
///
#define BOOST_PROTO_DECLTYPE_(Expr, Type)\
typedef detail::unspecified Type;
#endif
/// INTERNAL ONLY
///
#define UNREF(x) typename boost::remove_reference<x>::type
namespace detail
{
template<typename T> T make();
template<typename T>
char check_reference(T &);
template<typename T>
char (&check_reference(T const &))[2];
template<typename A0, typename A1>
struct comma_result
{
BOOST_PROTO_DECLTYPE_((proto::detail::make<A0>(), proto::detail::make<A1>()), type)
};
template<typename A0>
struct comma_result<A0, void>
{
typedef void type;
};
template<typename A1>
struct comma_result<void, A1>
{
typedef A1 type;
};
template<>
struct comma_result<void, void>
{
typedef void type;
};
template<typename T, typename U = T>
struct result_of_fixup
: mpl::if_<is_function<T>, T *, U>
{};
template<typename T, typename U>
struct result_of_fixup<T &, U>
: result_of_fixup<T, T>
{};
template<typename T, typename U>
struct result_of_fixup<T *, U>
: result_of_fixup<T, U>
{};
template<typename T, typename U>
struct result_of_fixup<T const, U>
: result_of_fixup<T, U>
{};
//// Tests for result_of_fixup
//struct bar {};
//BOOST_MPL_ASSERT((is_same<bar, result_of_fixup<bar>::type>));
//BOOST_MPL_ASSERT((is_same<bar const, result_of_fixup<bar const>::type>));
//BOOST_MPL_ASSERT((is_same<bar, result_of_fixup<bar &>::type>));
//BOOST_MPL_ASSERT((is_same<bar const, result_of_fixup<bar const &>::type>));
//BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(*)()>::type>));
//BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(* const)()>::type>));
//BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(* const &)()>::type>));
//BOOST_MPL_ASSERT((is_same<void(*)(), result_of_fixup<void(&)()>::type>));
} // namespace detail
namespace context
{
template<
typename Expr
, typename Context
, typename Tag BOOST_PROTO_FOR_DOXYGEN_ONLY(= typename Expr::proto_tag)
, long Arity BOOST_PROTO_FOR_DOXYGEN_ONLY(= Expr::proto_arity::value)
>
struct default_eval
{};
/// INTERNAL ONLY
///
#define BOOST_PROTO_UNARY_OP_RESULT(Op, Tag) \
template<typename Expr, typename Context> \
struct default_eval<Expr, Context, Tag, 1> \
{ \
private: \
typedef typename proto::result_of::arg_c<Expr, 0>::type e0; \
typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0; \
public: \
BOOST_PROTO_DECLTYPE_(Op proto::detail::make<r0>(), result_type) \
result_type operator ()(Expr &expr, Context &ctx) const \
{ \
return Op proto::eval(proto::arg_c<0>(expr), ctx); \
} \
}; \
/**/
/// INTERNAL ONLY
///
#define BOOST_PROTO_BINARY_OP_RESULT(Op, Tag) \
template<typename Expr, typename Context> \
struct default_eval<Expr, Context, Tag, 2> \
{ \
private: \
typedef typename proto::result_of::arg_c<Expr, 0>::type e0; \
typedef typename proto::result_of::arg_c<Expr, 1>::type e1; \
typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0; \
typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1; \
public: \
BOOST_PROTO_DECLTYPE_(proto::detail::make<r0>() Op proto::detail::make<r1>(), result_type)\
result_type operator ()(Expr &expr, Context &ctx) const \
{ \
return proto::eval(proto::arg_c<0>(expr), ctx) Op proto::eval(proto::arg_c<1>(expr), ctx);\
} \
}; \
/**/
BOOST_PROTO_UNARY_OP_RESULT(+, proto::tag::posit)
BOOST_PROTO_UNARY_OP_RESULT(-, proto::tag::negate)
BOOST_PROTO_UNARY_OP_RESULT(*, proto::tag::dereference)
BOOST_PROTO_UNARY_OP_RESULT(~, proto::tag::complement)
BOOST_PROTO_UNARY_OP_RESULT(&, proto::tag::address_of)
BOOST_PROTO_UNARY_OP_RESULT(!, proto::tag::logical_not)
BOOST_PROTO_UNARY_OP_RESULT(++, proto::tag::pre_inc)
BOOST_PROTO_UNARY_OP_RESULT(--, proto::tag::pre_dec)
BOOST_PROTO_BINARY_OP_RESULT(<<, proto::tag::shift_left)
BOOST_PROTO_BINARY_OP_RESULT(>>, proto::tag::shift_right)
BOOST_PROTO_BINARY_OP_RESULT(*, proto::tag::multiplies)
BOOST_PROTO_BINARY_OP_RESULT(/, proto::tag::divides)
BOOST_PROTO_BINARY_OP_RESULT(%, proto::tag::modulus)
BOOST_PROTO_BINARY_OP_RESULT(+, proto::tag::plus)
BOOST_PROTO_BINARY_OP_RESULT(-, proto::tag::minus)
BOOST_PROTO_BINARY_OP_RESULT(<, proto::tag::less)
BOOST_PROTO_BINARY_OP_RESULT(>, proto::tag::greater)
BOOST_PROTO_BINARY_OP_RESULT(<=, proto::tag::less_equal)
BOOST_PROTO_BINARY_OP_RESULT(>=, proto::tag::greater_equal)
BOOST_PROTO_BINARY_OP_RESULT(==, proto::tag::equal_to)
BOOST_PROTO_BINARY_OP_RESULT(!=, proto::tag::not_equal_to)
BOOST_PROTO_BINARY_OP_RESULT(||, proto::tag::logical_or)
BOOST_PROTO_BINARY_OP_RESULT(&&, proto::tag::logical_and)
BOOST_PROTO_BINARY_OP_RESULT(&, proto::tag::bitwise_and)
BOOST_PROTO_BINARY_OP_RESULT(|, proto::tag::bitwise_or)
BOOST_PROTO_BINARY_OP_RESULT(^, proto::tag::bitwise_xor)
BOOST_PROTO_BINARY_OP_RESULT(->*, proto::tag::mem_ptr)
BOOST_PROTO_BINARY_OP_RESULT(=, proto::tag::assign)
BOOST_PROTO_BINARY_OP_RESULT(<<=, proto::tag::shift_left_assign)
BOOST_PROTO_BINARY_OP_RESULT(>>=, proto::tag::shift_right_assign)
BOOST_PROTO_BINARY_OP_RESULT(*=, proto::tag::multiplies_assign)
BOOST_PROTO_BINARY_OP_RESULT(/=, proto::tag::divides_assign)
BOOST_PROTO_BINARY_OP_RESULT(%=, proto::tag::modulus_assign)
BOOST_PROTO_BINARY_OP_RESULT(+=, proto::tag::plus_assign)
BOOST_PROTO_BINARY_OP_RESULT(-=, proto::tag::minus_assign)
BOOST_PROTO_BINARY_OP_RESULT(&=, proto::tag::bitwise_and_assign)
BOOST_PROTO_BINARY_OP_RESULT(|=, proto::tag::bitwise_or_assign)
BOOST_PROTO_BINARY_OP_RESULT(^=, proto::tag::bitwise_xor_assign)
#undef BOOST_PROTO_UNARY_OP_RESULT
#undef BOOST_PROTO_BINARY_OP_RESULT
template<typename Expr, typename Context>
struct default_eval<Expr, Context, proto::tag::terminal, 0>
{
typedef
typename mpl::if_<
is_const<Expr>
, typename proto::result_of::arg<Expr>::const_reference
, typename proto::result_of::arg<Expr>::reference
>::type
result_type;
result_type operator ()(Expr &expr, Context &) const
{
return proto::arg(expr);
}
};
// Handle post-increment specially.
template<typename Expr, typename Context>
struct default_eval<Expr, Context, proto::tag::post_inc, 1>
{
private:
typedef typename proto::result_of::arg_c<Expr, 0>::type e0;
typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
public:
BOOST_PROTO_DECLTYPE_(proto::detail::make<r0>() ++, result_type)
result_type operator ()(Expr &expr, Context &ctx) const
{
return proto::eval(proto::arg_c<0>(expr), ctx) ++;
}
};
// Handle post-decrement specially.
template<typename Expr, typename Context>
struct default_eval<Expr, Context, proto::tag::post_dec, 1>
{
private:
typedef typename proto::result_of::arg_c<Expr, 0>::type e0;
typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
public:
BOOST_PROTO_DECLTYPE_(proto::detail::make<r0>() --, result_type)
result_type operator ()(Expr &expr, Context &ctx) const
{
return proto::eval(proto::arg_c<0>(expr), ctx) --;
}
};
// Handle subscript specially.
template<typename Expr, typename Context>
struct default_eval<Expr, Context, proto::tag::subscript, 2>
{
private:
typedef typename proto::result_of::arg_c<Expr, 0>::type e0;
typedef typename proto::result_of::arg_c<Expr, 1>::type e1;
typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
public:
BOOST_PROTO_DECLTYPE_(proto::detail::make<r0>()[proto::detail::make<r1>()], result_type)
result_type operator ()(Expr &expr, Context &ctx) const
{
return proto::eval(proto::arg_c<0>(expr), ctx)[proto::eval(proto::arg_c<1>(expr), ctx)];
}
};
// Handle if_else_ specially.
template<typename Expr, typename Context>
struct default_eval<Expr, Context, proto::tag::if_else_, 3>
{
private:
typedef typename proto::result_of::arg_c<Expr, 0>::type e0;
typedef typename proto::result_of::arg_c<Expr, 1>::type e1;
typedef typename proto::result_of::arg_c<Expr, 2>::type e2;
typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
typedef typename proto::result_of::eval<UNREF(e2), Context>::type r2;
public:
BOOST_PROTO_DECLTYPE_(
proto::detail::make<r0>()
? proto::detail::make<r1>()
: proto::detail::make<r2>()
, result_type
)
result_type operator ()(Expr &expr, Context &ctx) const
{
return proto::eval(proto::arg_c<0>(expr), ctx)
? proto::eval(proto::arg_c<1>(expr), ctx)
: proto::eval(proto::arg_c<2>(expr), ctx);
}
};
// Handle comma specially.
template<typename Expr, typename Context>
struct default_eval<Expr, Context, proto::tag::comma, 2>
{
private:
typedef typename proto::result_of::arg_c<Expr, 0>::type e0;
typedef typename proto::result_of::arg_c<Expr, 1>::type e1;
typedef typename proto::result_of::eval<UNREF(e0), Context>::type r0;
typedef typename proto::result_of::eval<UNREF(e1), Context>::type r1;
public:
typedef typename proto::detail::comma_result<r0, r1>::type result_type;
result_type operator ()(Expr &expr, Context &ctx) const
{
return proto::eval(proto::arg_c<0>(expr), ctx), proto::eval(proto::arg_c<1>(expr), ctx);
}
};
// Handle function specially
#define EVAL_TYPE(Z, N, DATA) \
typename proto::result_of::eval< \
typename remove_reference<typename proto::result_of::arg_c<DATA, N>::type>::type\
, Context \
>::type
#define EVAL(Z, N, DATA) \
proto::eval(proto::arg_c<N>(DATA), context)
#define BOOST_PP_ITERATION_PARAMS_1 (3, (0, BOOST_PROTO_MAX_ARITY, <boost/xpressive/proto/context/default.hpp>))
#include BOOST_PP_ITERATE()
#undef EVAL_TYPE
#undef EVAL
/// default_context
///
struct default_context
{
/// default_context::eval
///
template<typename Expr, typename ThisContext = default_context const>
struct eval
: default_eval<Expr, ThisContext>
{};
};
} // namespace context
}} // namespace boost::proto
#undef UNREF
#endif
#else
#define N BOOST_PP_ITERATION()
template<typename Expr, typename Context>
struct default_eval<Expr, Context, proto::tag::function, N>
{
typedef
typename proto::detail::result_of_fixup<EVAL_TYPE(~, 0, Expr)>::type
function_type;
typedef
typename boost::result_of<
function_type(BOOST_PP_ENUM_SHIFTED(BOOST_PP_MAX(N, 1), EVAL_TYPE, Expr))
>::type
result_type;
result_type operator ()(Expr &expr, Context &context) const
{
return EVAL(~, 0, expr)(BOOST_PP_ENUM_SHIFTED(BOOST_PP_MAX(N, 1), EVAL, expr));
}
};
#undef N
#endif
