boost/proto/expr.hpp
#ifndef BOOST_PP_IS_ITERATING
///////////////////////////////////////////////////////////////////////////////
/// \file expr.hpp
/// Contains definition of expr\<\> class template.
//
// 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_EXPR_HPP_EAN_04_01_2005
#define BOOST_PROTO_EXPR_HPP_EAN_04_01_2005
#include <boost/proto/detail/prefix.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/arithmetic/dec.hpp>
#include <boost/preprocessor/selection/max.hpp>
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/repetition/repeat.hpp>
#include <boost/preprocessor/repetition/repeat_from_to.hpp>
#include <boost/preprocessor/repetition/enum_trailing.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
#include <boost/preprocessor/repetition/enum_trailing_binary_params.hpp>
#include <boost/utility/addressof.hpp>
#include <boost/proto/proto_fwd.hpp>
#include <boost/proto/args.hpp>
#include <boost/proto/traits.hpp>
#include <boost/proto/detail/suffix.hpp>
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma warning(push)
# pragma warning(disable : 4510) // default constructor could not be generated
# pragma warning(disable : 4512) // assignment operator could not be generated
# pragma warning(disable : 4610) // user defined constructor required
#endif
namespace boost { namespace proto
{
namespace detail
{
/// INTERNAL ONLY
///
#define BOOST_PROTO_CHILD(Z, N, DATA) \
typedef typename Args::BOOST_PP_CAT(child, N) BOOST_PP_CAT(proto_child, N); \
BOOST_PP_CAT(proto_child, N) BOOST_PP_CAT(child, N); \
/**< INTERNAL ONLY */
/// INTERNAL ONLY
///
#define BOOST_PROTO_VOID(Z, N, DATA) \
typedef void BOOST_PP_CAT(proto_child, N); \
/**< INTERNAL ONLY */
struct not_a_valid_type
{
private:
not_a_valid_type()
{}
};
template<typename Tag, typename Arg>
struct address_of_hack
{
typedef not_a_valid_type type;
};
template<typename Expr>
struct address_of_hack<proto::tag::address_of, Expr &>
{
typedef Expr *type;
};
template<typename X, std::size_t N, typename Y>
void checked_copy(X (&x)[N], Y (&y)[N])
{
for(std::size_t i = 0; i < N; ++i)
{
y[i] = x[i];
}
}
template<typename T, std::size_t N>
struct if_is_array
{};
template<typename T, std::size_t N>
struct if_is_array<T[N], N>
{
typedef int type;
};
}
namespace result_of
{
/// \brief A helper metafunction for computing the
/// return type of \c proto::expr\<\>::operator().
template<typename Sig, typename This, typename Domain>
struct funop;
#define BOOST_PP_ITERATION_PARAMS_1 (3, (0, BOOST_PP_DEC(BOOST_PROTO_MAX_FUNCTION_CALL_ARITY), <boost/proto/detail/funop.hpp>))
#include BOOST_PP_ITERATE()
}
// TODO consider adding a basic_expr<> that doesn't have operator=,
// operator[] or operator() for use by BOOST_PROTO_BASIC_EXTENDS().
// Those member functions are unused in that case, and only slow
// down instantiations. basic_expr::proto_base_expr can still be
// expr<> because uses of proto_base_expr in proto::matches<> shouldn't
// case the expr<> type to be instantiated. (<-- Check that assumtion!)
// OR, should expr<>::proto_base_expr be a typedef for basic_expr<>?
BOOST_PROTO_BEGIN_ADL_NAMESPACE(exprns_)
#define BOOST_PP_ITERATION_PARAMS_1 (3, (0, BOOST_PROTO_MAX_ARITY, <boost/proto/expr.hpp>))
#include BOOST_PP_ITERATE()
BOOST_PROTO_END_ADL_NAMESPACE(exprns_)
#undef BOOST_PROTO_CHILD
#undef BOOST_PROTO_VOID
/// \brief Lets you inherit the interface of an expression
/// while hiding from Proto the fact that the type is a Proto
/// expression.
template<typename Expr>
struct unexpr
: Expr
{
BOOST_PROTO_UNEXPR()
explicit unexpr(Expr const &expr)
: Expr(expr)
{}
using Expr::operator =;
};
}}
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
# pragma warning(pop)
#endif
#endif // BOOST_PROTO_EXPR_HPP_EAN_04_01_2005
// For gcc 4.4 compatability, we must include the
// BOOST_PP_ITERATION_DEPTH test inside an #else clause.
#else // BOOST_PP_IS_ITERATING
#if BOOST_PP_ITERATION_DEPTH() == 1
#define ARG_COUNT BOOST_PP_MAX(1, BOOST_PP_ITERATION())
#define IS_TERMINAL 0 == BOOST_PP_ITERATION()
/// \brief Representation of a node in an expression tree.
///
/// \c proto::expr\<\> is a node in an expression template tree. It
/// is a container for its child sub-trees. It also serves as
/// the terminal nodes of the tree.
///
/// \c Tag is type that represents the operation encoded by
/// this expression. It is typically one of the structs
/// in the \c boost::proto::tag namespace, but it doesn't
/// have to be.
///
/// \c Args is a type list representing the type of the children
/// of this expression. It is an instantiation of one
/// of \c proto::list1\<\>, \c proto::list2\<\>, etc. The
/// child types must all themselves be either \c expr\<\>
/// or <tt>proto::expr\<\>&</tt>. If \c Args is an
/// instantiation of \c proto::term\<\> then this
/// \c expr\<\> type represents a terminal expression;
/// the parameter to the \c proto::term\<\> template
/// represents the terminal's value type.
///
/// \c Arity is an integral constant representing the number of child
/// nodes this node contains. If \c Arity is 0, then this
/// node is a terminal.
///
/// \c proto::expr\<\> is a valid Fusion random-access sequence, where
/// the elements of the sequence are the child expressions.
template<typename Tag, typename Args>
struct expr<Tag, Args, BOOST_PP_ITERATION() >
{
typedef Tag proto_tag;
BOOST_STATIC_CONSTANT(long, proto_arity_c = BOOST_PP_ITERATION());
typedef mpl::long_<BOOST_PP_ITERATION() > proto_arity;
typedef expr proto_base_expr;
typedef Args proto_args;
typedef default_domain proto_domain;
BOOST_PROTO_FUSION_DEFINE_TAG(proto::tag::proto_expr)
typedef expr proto_derived_expr;
typedef void proto_is_expr_; /**< INTERNAL ONLY */
BOOST_PP_REPEAT(ARG_COUNT, BOOST_PROTO_CHILD, ~)
BOOST_PP_REPEAT_FROM_TO(ARG_COUNT, BOOST_PROTO_MAX_ARITY, BOOST_PROTO_VOID, ~)
/// \return *this
///
expr const &proto_base() const
{
return *this;
}
/// \overload
///
expr &proto_base()
{
return *this;
}
/// \return A new \c expr\<\> object initialized with the specified
/// arguments.
///
template<BOOST_PP_ENUM_PARAMS(ARG_COUNT, typename A)>
static expr const make(BOOST_PP_ENUM_BINARY_PARAMS(ARG_COUNT, A, const &a))
{
expr that = {BOOST_PP_ENUM_PARAMS(ARG_COUNT, a)};
return that;
}
#if IS_TERMINAL
/// \overload
///
template<typename A0>
static expr const make(A0 &a0)
{
expr that = {a0};
return that;
}
/// \overload
///
template<typename A0, std::size_t N>
static expr const make(A0 (&a0)[N], typename detail::if_is_array<proto_child0, N>::type = 0)
{
expr that;
detail::checked_copy(a0, that.child0);
return that;
}
/// \overload
///
template<typename A0, std::size_t N>
static expr const make(A0 const (&a0)[N], typename detail::if_is_array<proto_child0, N>::type = 0)
{
expr that;
detail::checked_copy(a0, that.child0);
return that;
}
#endif
#if 1 == BOOST_PP_ITERATION()
/// If \c Tag is \c boost::proto::tag::address_of and \c proto_child0 is
/// <tt>T&</tt>, then \c address_of_hack_type_ is <tt>T*</tt>.
/// Otherwise, it is some undefined type.
typedef typename detail::address_of_hack<Tag, proto_child0>::type address_of_hack_type_;
/// \return The address of <tt>this->child0</tt> if \c Tag is
/// \c boost::proto::tag::address_of. Otherwise, this function will
/// fail to compile.
///
/// \attention Proto overloads <tt>operator&</tt>, which means that
/// proto-ified objects cannot have their addresses taken, unless we use
/// the following hack to make \c &x implicitly convertible to \c X*.
operator address_of_hack_type_() const
{
return boost::addressof(this->child0);
}
#else
/// INTERNAL ONLY
///
typedef detail::not_a_valid_type address_of_hack_type_;
#endif
/// Assignment
///
/// \param a The rhs.
/// \return A new \c expr\<\> node representing an assignment of \c a to \c *this.
template<typename A>
proto::expr<
proto::tag::assign
, list2<expr const &, typename result_of::as_child<A>::type>
> const
operator =(A &a) const
{
proto::expr<
proto::tag::assign
, list2<expr const &, typename result_of::as_child<A>::type>
> that = {*this, proto::as_child(a)};
return that;
}
/// \overload
///
template<typename A>
proto::expr<
proto::tag::assign
, list2<expr const &, typename result_of::as_child<A const>::type>
> const
operator =(A const &a) const
{
proto::expr<
proto::tag::assign
, list2<expr const &, typename result_of::as_child<A const>::type>
> that = {*this, proto::as_child(a)};
return that;
}
#if IS_TERMINAL
/// \overload
///
template<typename A>
proto::expr<
proto::tag::assign
, list2<expr &, typename result_of::as_child<A>::type>
> const
operator =(A &a)
{
proto::expr<
proto::tag::assign
, list2<expr &, typename result_of::as_child<A>::type>
> that = {*this, proto::as_child(a)};
return that;
}
/// \overload
///
template<typename A>
proto::expr<
proto::tag::assign
, list2<expr &, typename result_of::as_child<A const>::type>
> const
operator =(A const &a)
{
proto::expr<
proto::tag::assign
, list2<expr &, typename result_of::as_child<A const>::type>
> that = {*this, proto::as_child(a)};
return that;
}
#endif
/// Subscript
///
/// \param a The rhs.
/// \return A new \c expr\<\> node representing \c *this subscripted with \c a.
template<typename A>
proto::expr<
proto::tag::subscript
, list2<expr const &, typename result_of::as_child<A>::type>
> const
operator [](A &a) const
{
proto::expr<
proto::tag::subscript
, list2<expr const &, typename result_of::as_child<A>::type>
> that = {*this, proto::as_child(a)};
return that;
}
/// \overload
///
template<typename A>
proto::expr<
proto::tag::subscript
, list2<expr const &, typename result_of::as_child<A const>::type> > const
operator [](A const &a) const
{
proto::expr<
proto::tag::subscript
, list2<expr const &, typename result_of::as_child<A const>::type>
> that = {*this, proto::as_child(a)};
return that;
}
#if IS_TERMINAL
/// \overload
///
template<typename A>
proto::expr<
proto::tag::subscript
, list2<expr &, typename result_of::as_child<A>::type>
> const
operator [](A &a)
{
proto::expr<
proto::tag::subscript
, list2<expr &, typename result_of::as_child<A>::type>
> that = {*this, proto::as_child(a)};
return that;
}
/// \overload
///
template<typename A>
proto::expr<
proto::tag::subscript
, list2<expr &, typename result_of::as_child<A const>::type>
> const
operator [](A const &a)
{
proto::expr<
proto::tag::subscript
, list2<expr &, typename result_of::as_child<A const>::type>
> that = {*this, proto::as_child(a)};
return that;
}
#endif
/// Encodes the return type of \c expr\<\>::operator(), for use with \c boost::result_of\<\>
///
template<typename Sig>
struct result
{
typedef typename result_of::funop<Sig, expr, default_domain>::type const type;
};
/// Function call
///
/// \return A new \c expr\<\> node representing the function invocation of \c (*this)().
proto::expr<proto::tag::function, list1<expr const &> > const
operator ()() const
{
proto::expr<proto::tag::function, list1<expr const &> > that = {*this};
return that;
}
#if IS_TERMINAL
/// \overload
///
proto::expr<proto::tag::function, list1<expr &> > const
operator ()()
{
proto::expr<proto::tag::function, list1<expr &> > that = {*this};
return that;
}
#endif
#define BOOST_PP_ITERATION_PARAMS_2 (3, (1, BOOST_PP_DEC(BOOST_PROTO_MAX_FUNCTION_CALL_ARITY), <boost/proto/expr.hpp>))
#include BOOST_PP_ITERATE()
};
#undef ARG_COUNT
#undef IS_TERMINAL
#elif BOOST_PP_ITERATION_DEPTH() == 2
#define N BOOST_PP_ITERATION()
/// \overload
///
template<BOOST_PP_ENUM_PARAMS(N, typename A)>
typename result_of::BOOST_PP_CAT(funop, N)<
expr const
, default_domain BOOST_PP_ENUM_TRAILING_PARAMS(N, const A)
>::type const
operator ()(BOOST_PP_ENUM_BINARY_PARAMS(N, A, const &a)) const
{
return result_of::BOOST_PP_CAT(funop, N)<
expr const
, default_domain BOOST_PP_ENUM_TRAILING_PARAMS(N, const A)
>::call(*this BOOST_PP_ENUM_TRAILING_PARAMS(N, a));
}
#if IS_TERMINAL
/// \overload
///
template<BOOST_PP_ENUM_PARAMS(N, typename A)>
typename result_of::BOOST_PP_CAT(funop, N)<
expr
, default_domain BOOST_PP_ENUM_TRAILING_PARAMS(N, const A)
>::type const
operator ()(BOOST_PP_ENUM_BINARY_PARAMS(N, A, const &a))
{
return result_of::BOOST_PP_CAT(funop, N)<
expr
, default_domain BOOST_PP_ENUM_TRAILING_PARAMS(N, const A)
>::call(*this BOOST_PP_ENUM_TRAILING_PARAMS(N, a));
}
#endif
#undef N
#endif // BOOST_PP_ITERATION_DEPTH()
#endif
