boost/proto/detail/traits.hpp
#if !defined(BOOST_PROTO_DONT_USE_PREPROCESSED_FILES)
#include <boost/proto/detail/preprocessed/traits.hpp>
#elif !defined(BOOST_PP_IS_ITERATING)
#define BOOST_PROTO_CHILD(Z, N, DATA) \
/** INTERNAL ONLY */ \
typedef BOOST_PP_CAT(DATA, N) BOOST_PP_CAT(proto_child, N); \
/**/
#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
#pragma wave option(preserve: 2, line: 0, output: "preprocessed/traits.hpp")
#endif
///////////////////////////////////////////////////////////////////////////////
/// \file traits.hpp
/// Definitions of proto::function, proto::nary_expr and proto::result_of::child_c
//
// 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)
#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
#pragma wave option(preserve: 1)
#endif
#define BOOST_PP_ITERATION_PARAMS_1 \
(3, (0, BOOST_PROTO_MAX_ARITY, <boost/proto/detail/traits.hpp>))
#include BOOST_PP_ITERATE()
#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
#pragma wave option(output: null)
#endif
#undef BOOST_PROTO_CHILD
#else // BOOST_PP_IS_ITERATING
#define N BOOST_PP_ITERATION()
#if N > 0
/// \brief A metafunction for generating function-call expression types,
/// a grammar element for matching function-call expressions, and a
/// PrimitiveTransform that dispatches to the <tt>pass_through\<\></tt>
/// transform.
template<BOOST_PP_ENUM_PARAMS(N, typename A)>
struct function
#if N != BOOST_PROTO_MAX_ARITY
<
BOOST_PP_ENUM_PARAMS(N, A)
BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_SUB(BOOST_PROTO_MAX_ARITY, N), void BOOST_PP_INTERCEPT)
>
#endif
: proto::transform<
function<
BOOST_PP_ENUM_PARAMS(N, A)
BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_SUB(BOOST_PROTO_MAX_ARITY, N), void BOOST_PP_INTERCEPT)
>
, int
>
{
typedef proto::expr<proto::tag::function, BOOST_PP_CAT(list, N)<BOOST_PP_ENUM_PARAMS(N, A)>, N> type;
typedef proto::basic_expr<proto::tag::function, BOOST_PP_CAT(list, N)<BOOST_PP_ENUM_PARAMS(N, A)>, N> proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl
: detail::pass_through_impl<function, Expr, State, Data>
{};
/// INTERNAL ONLY
typedef proto::tag::function proto_tag;
BOOST_PP_REPEAT(N, BOOST_PROTO_CHILD, A)
BOOST_PP_REPEAT_FROM_TO(
N
, BOOST_PROTO_MAX_ARITY
, BOOST_PROTO_CHILD
, detail::if_vararg<BOOST_PP_CAT(A, BOOST_PP_DEC(N))> BOOST_PP_INTERCEPT
)
};
/// \brief A metafunction for generating n-ary expression types with a
/// specified tag type,
/// a grammar element for matching n-ary expressions, and a
/// PrimitiveTransform that dispatches to the <tt>pass_through\<\></tt>
/// transform.
///
/// Use <tt>nary_expr\<_, vararg\<_\> \></tt> as a grammar element to match any
/// n-ary expression; that is, any non-terminal.
template<typename Tag BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
struct nary_expr
#if N != BOOST_PROTO_MAX_ARITY
<
Tag
BOOST_PP_ENUM_TRAILING_PARAMS(N, A)
BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_SUB(BOOST_PROTO_MAX_ARITY, N), void BOOST_PP_INTERCEPT)
>
#endif
: proto::transform<
nary_expr<
Tag
BOOST_PP_ENUM_TRAILING_PARAMS(N, A)
BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_SUB(BOOST_PROTO_MAX_ARITY, N), void BOOST_PP_INTERCEPT)
>
, int
>
{
typedef proto::expr<Tag, BOOST_PP_CAT(list, N)<BOOST_PP_ENUM_PARAMS(N, A)>, N> type;
typedef proto::basic_expr<Tag, BOOST_PP_CAT(list, N)<BOOST_PP_ENUM_PARAMS(N, A)>, N> proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl
: detail::pass_through_impl<nary_expr, Expr, State, Data>
{};
/// INTERNAL ONLY
typedef Tag proto_tag;
BOOST_PP_REPEAT(N, BOOST_PROTO_CHILD, A)
BOOST_PP_REPEAT_FROM_TO(
N
, BOOST_PROTO_MAX_ARITY
, BOOST_PROTO_CHILD
, detail::if_vararg<BOOST_PP_CAT(A, BOOST_PP_DEC(N))> BOOST_PP_INTERCEPT
)
};
namespace detail
{
template<
template<BOOST_PP_ENUM_PARAMS(N, typename BOOST_PP_INTERCEPT)> class T
, BOOST_PP_ENUM_PARAMS(N, typename A)
>
struct is_callable_<T<BOOST_PP_ENUM_PARAMS(N, A)> BOOST_PROTO_TEMPLATE_ARITY_PARAM(N)>
: is_same<BOOST_PP_CAT(A, BOOST_PP_DEC(N)), callable>
{};
}
#endif
namespace result_of
{
/// \brief A metafunction that returns the type of the Nth child
/// of a Proto expression.
///
/// A metafunction that returns the type of the Nth child
/// of a Proto expression. \c N must be less than
/// \c Expr::proto_arity::value.
template<typename Expr>
struct child_c<Expr, N>
{
/// Verify that we are not operating on a terminal
BOOST_STATIC_ASSERT(0 != Expr::proto_arity_c);
/// The raw type of the Nth child as it is stored within
/// \c Expr. This may be a value or a reference
typedef typename Expr::BOOST_PP_CAT(proto_child, N) value_type;
/// The "value" type of the child, suitable for return by value,
/// computed as follows:
/// \li <tt>T const &</tt> becomes <tt>T</tt>
/// \li <tt>T &</tt> becomes <tt>T</tt>
/// \li <tt>T</tt> becomes <tt>T</tt>
typedef typename detail::expr_traits<typename Expr::BOOST_PP_CAT(proto_child, N)>::value_type type;
};
template<typename Expr>
struct child_c<Expr &, N>
{
/// Verify that we are not operating on a terminal
BOOST_STATIC_ASSERT(0 != Expr::proto_arity_c);
/// The raw type of the Nth child as it is stored within
/// \c Expr. This may be a value or a reference
typedef typename Expr::BOOST_PP_CAT(proto_child, N) value_type;
/// The "reference" type of the child, suitable for return by
/// reference, computed as follows:
/// \li <tt>T const &</tt> becomes <tt>T const &</tt>
/// \li <tt>T &</tt> becomes <tt>T &</tt>
/// \li <tt>T</tt> becomes <tt>T &</tt>
typedef typename detail::expr_traits<typename Expr::BOOST_PP_CAT(proto_child, N)>::reference type;
/// INTERNAL ONLY
///
BOOST_FORCEINLINE
static type call(Expr &e)
{
return e.proto_base().BOOST_PP_CAT(child, N);
}
};
template<typename Expr>
struct child_c<Expr const &, N>
{
/// Verify that we are not operating on a terminal
BOOST_STATIC_ASSERT(0 != Expr::proto_arity_c);
/// The raw type of the Nth child as it is stored within
/// \c Expr. This may be a value or a reference
typedef typename Expr::BOOST_PP_CAT(proto_child, N) value_type;
/// The "const reference" type of the child, suitable for return by
/// const reference, computed as follows:
/// \li <tt>T const &</tt> becomes <tt>T const &</tt>
/// \li <tt>T &</tt> becomes <tt>T &</tt>
/// \li <tt>T</tt> becomes <tt>T const &</tt>
typedef typename detail::expr_traits<typename Expr::BOOST_PP_CAT(proto_child, N)>::const_reference type;
/// INTERNAL ONLY
///
BOOST_FORCEINLINE
static type call(Expr const &e)
{
return e.proto_base().BOOST_PP_CAT(child, N);
}
};
}
#undef N
#endif
