#ifndef BOOST_PP_IS_ITERATING | |
/////////////////////////////////////////////////////////////////////////////// | |
/// \file call.hpp | |
/// Contains definition of the call<> transform. | |
// | |
// 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_TRANSFORM_CALL_HPP_EAN_11_02_2007 | |
#define BOOST_PROTO_TRANSFORM_CALL_HPP_EAN_11_02_2007 | |
#include <boost/preprocessor/cat.hpp> | |
#include <boost/preprocessor/facilities/intercept.hpp> | |
#include <boost/preprocessor/iteration/iterate.hpp> | |
#include <boost/preprocessor/repetition/enum.hpp> | |
#include <boost/preprocessor/repetition/repeat.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/ref.hpp> | |
#include <boost/utility/result_of.hpp> | |
#include <boost/proto/proto_fwd.hpp> | |
#include <boost/proto/traits.hpp> | |
#include <boost/proto/transform/impl.hpp> | |
#include <boost/proto/detail/as_lvalue.hpp> | |
#include <boost/proto/detail/poly_function.hpp> | |
namespace boost { namespace proto | |
{ | |
/// \brief Wrap \c PrimitiveTransform so that <tt>when\<\></tt> knows | |
/// it is callable. Requires that the parameter is actually a | |
/// PrimitiveTransform. | |
/// | |
/// This form of <tt>call\<\></tt> is useful for annotating an | |
/// arbitrary PrimitiveTransform as callable when using it with | |
/// <tt>when\<\></tt>. Consider the following transform, which | |
/// is parameterized with another transform. | |
/// | |
/// \code | |
/// template<typename Grammar> | |
/// struct Foo | |
/// : when< | |
/// unary_plus<Grammar> | |
/// , Grammar(_child) // May or may not work. | |
/// > | |
/// {}; | |
/// \endcode | |
/// | |
/// The problem with the above is that <tt>when\<\></tt> may or | |
/// may not recognize \c Grammar as callable, depending on how | |
/// \c Grammar is implemented. (See <tt>is_callable\<\></tt> for | |
/// a discussion of this issue.) You can guard against | |
/// the issue by wrapping \c Grammar in <tt>call\<\></tt>, such | |
/// as: | |
/// | |
/// \code | |
/// template<typename Grammar> | |
/// struct Foo | |
/// : when< | |
/// unary_plus<Grammar> | |
/// , call<Grammar>(_child) // OK, this works | |
/// > | |
/// {}; | |
/// \endcode | |
/// | |
/// The above could also have been written as: | |
/// | |
/// \code | |
/// template<typename Grammar> | |
/// struct Foo | |
/// : when< | |
/// unary_plus<Grammar> | |
/// , call<Grammar(_child)> // OK, this works, too | |
/// > | |
/// {}; | |
/// \endcode | |
template<typename PrimitiveTransform> | |
struct call | |
: PrimitiveTransform | |
{}; | |
/// \brief Either call the PolymorphicFunctionObject with 0 | |
/// arguments, or invoke the PrimitiveTransform with 3 | |
/// arguments. | |
template<typename Fun> | |
struct call<Fun()> : transform<call<Fun()> > | |
{ | |
/// INTERNAL ONLY | |
template<typename Expr, typename State, typename Data, bool B> | |
struct impl2 | |
: transform_impl<Expr, State, Data> | |
{ | |
typedef typename BOOST_PROTO_RESULT_OF<Fun()>::type result_type; | |
result_type operator()( | |
typename impl2::expr_param | |
, typename impl2::state_param | |
, typename impl2::data_param | |
) const | |
{ | |
return Fun()(); | |
} | |
}; | |
/// INTERNAL ONLY | |
template<typename Expr, typename State, typename Data> | |
struct impl2<Expr, State, Data, true> | |
: Fun::template impl<Expr, State, Data> | |
{}; | |
/// Either call the PolymorphicFunctionObject \c Fun with 0 arguments; or | |
/// invoke the PrimitiveTransform \c Fun with 3 arguments: the current | |
/// expression, state, and data. | |
/// | |
/// If \c Fun is a nullary PolymorphicFunctionObject, return <tt>Fun()()</tt>. | |
/// Otherwise, return <tt>Fun()(e, s, d)</tt>. | |
/// | |
/// \param e The current expression | |
/// \param s The current state | |
/// \param d An arbitrary data | |
/// If \c Fun is a nullary PolymorphicFunctionObject, \c type is a typedef | |
/// for <tt>boost::result_of\<Fun()\>::type</tt>. Otherwise, it is | |
/// a typedef for <tt>boost::result_of\<Fun(Expr, State, Data)\>::type</tt>. | |
template<typename Expr, typename State, typename Data> | |
struct impl | |
: impl2<Expr, State, Data, is_transform<Fun>::value> | |
{}; | |
}; | |
/// \brief Either call the PolymorphicFunctionObject with 1 | |
/// argument, or invoke the PrimitiveTransform with 3 | |
/// arguments. | |
template<typename Fun, typename A0> | |
struct call<Fun(A0)> : transform<call<Fun(A0)> > | |
{ | |
template<typename Expr, typename State, typename Data, bool B> | |
struct impl2 | |
: transform_impl<Expr, State, Data> | |
{ | |
typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; | |
typedef typename detail::poly_function_traits<Fun, Fun(a0)>::result_type result_type; | |
result_type operator ()( | |
typename impl2::expr_param e | |
, typename impl2::state_param s | |
, typename impl2::data_param d | |
) const | |
{ | |
return typename detail::poly_function_traits<Fun, Fun(a0)>::function_type()( | |
detail::as_lvalue(typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d)) | |
); | |
} | |
}; | |
template<typename Expr, typename State, typename Data> | |
struct impl2<Expr, State, Data, true> | |
: transform_impl<Expr, State, Data> | |
{ | |
typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; | |
typedef typename Fun::template impl<a0, State, Data>::result_type result_type; | |
result_type operator ()( | |
typename impl2::expr_param e | |
, typename impl2::state_param s | |
, typename impl2::data_param d | |
) const | |
{ | |
return typename Fun::template impl<a0, State, Data>()( | |
typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d) | |
, s | |
, d | |
); | |
} | |
}; | |
/// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt> and \c X | |
/// be the type of \c x. | |
/// If \c Fun is a unary PolymorphicFunctionObject that accepts \c x, | |
/// then \c type is a typedef for <tt>boost::result_of\<Fun(X)\>::type</tt>. | |
/// Otherwise, it is a typedef for <tt>boost::result_of\<Fun(X, State, Data)\>::type</tt>. | |
/// Either call the PolymorphicFunctionObject with 1 argument: | |
/// the result of applying the \c A0 transform; or | |
/// invoke the PrimitiveTransform with 3 arguments: | |
/// result of applying the \c A0 transform, the state, and the | |
/// data. | |
/// | |
/// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt>. | |
/// If \c Fun is a unary PolymorphicFunctionObject that accepts \c x, | |
/// then return <tt>Fun()(x)</tt>. Otherwise, return | |
/// <tt>Fun()(x, s, d)</tt>. | |
/// | |
/// \param e The current expression | |
/// \param s The current state | |
/// \param d An arbitrary data | |
template<typename Expr, typename State, typename Data> | |
struct impl | |
: impl2<Expr, State, Data, is_transform<Fun>::value> | |
{}; | |
}; | |
/// \brief Either call the PolymorphicFunctionObject with 2 | |
/// arguments, or invoke the PrimitiveTransform with 3 | |
/// arguments. | |
template<typename Fun, typename A0, typename A1> | |
struct call<Fun(A0, A1)> : transform<call<Fun(A0, A1)> > | |
{ | |
template<typename Expr, typename State, typename Data, bool B> | |
struct impl2 | |
: transform_impl<Expr, State, Data> | |
{ | |
typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; | |
typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; | |
typedef typename detail::poly_function_traits<Fun, Fun(a0, a1)>::result_type result_type; | |
result_type operator ()( | |
typename impl2::expr_param e | |
, typename impl2::state_param s | |
, typename impl2::data_param d | |
) const | |
{ | |
return typename detail::poly_function_traits<Fun, Fun(a0, a1)>::function_type()( | |
detail::as_lvalue(typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d)) | |
, detail::as_lvalue(typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d)) | |
); | |
} | |
}; | |
template<typename Expr, typename State, typename Data> | |
struct impl2<Expr, State, Data, true> | |
: transform_impl<Expr, State, Data> | |
{ | |
typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; | |
typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; | |
typedef typename Fun::template impl<a0, a1, Data>::result_type result_type; | |
result_type operator ()( | |
typename impl2::expr_param e | |
, typename impl2::state_param s | |
, typename impl2::data_param d | |
) const | |
{ | |
return typename Fun::template impl<a0, a1, Data>()( | |
typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d) | |
, typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d) | |
, d | |
); | |
} | |
}; | |
/// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt> and \c X | |
/// be the type of \c x. | |
/// Let \c y be <tt>when\<_, A1\>()(e, s, d)</tt> and \c Y | |
/// be the type of \c y. | |
/// If \c Fun is a binary PolymorphicFunction object that accepts \c x | |
/// and \c y, then \c type is a typedef for | |
/// <tt>boost::result_of\<Fun(X, Y)\>::type</tt>. Otherwise, it is | |
/// a typedef for <tt>boost::result_of\<Fun(X, Y, Data)\>::type</tt>. | |
/// Either call the PolymorphicFunctionObject with 2 arguments: | |
/// the result of applying the \c A0 transform, and the | |
/// result of applying the \c A1 transform; or invoke the | |
/// PrimitiveTransform with 3 arguments: the result of applying | |
/// the \c A0 transform, the result of applying the \c A1 | |
/// transform, and the data. | |
/// | |
/// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt>. | |
/// Let \c y be <tt>when\<_, A1\>()(e, s, d)</tt>. | |
/// If \c Fun is a binary PolymorphicFunction object that accepts \c x | |
/// and \c y, return <tt>Fun()(x, y)</tt>. Otherwise, return | |
/// <tt>Fun()(x, y, d)</tt>. | |
/// | |
/// \param e The current expression | |
/// \param s The current state | |
/// \param d An arbitrary data | |
template<typename Expr, typename State, typename Data> | |
struct impl | |
: impl2<Expr, State, Data, is_transform<Fun>::value> | |
{}; | |
}; | |
/// \brief Call the PolymorphicFunctionObject or the | |
/// PrimitiveTransform with the current expression, state | |
/// and data, transformed according to \c A0, \c A1, and | |
/// \c A2, respectively. | |
template<typename Fun, typename A0, typename A1, typename A2> | |
struct call<Fun(A0, A1, A2)> : transform<call<Fun(A0, A1, A2)> > | |
{ | |
template<typename Expr, typename State, typename Data, bool B> | |
struct impl2 | |
: transform_impl<Expr, State, Data> | |
{ | |
typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; | |
typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; | |
typedef typename when<_, A2>::template impl<Expr, State, Data>::result_type a2; | |
typedef typename detail::poly_function_traits<Fun, Fun(a0, a1, a2)>::result_type result_type; | |
result_type operator ()( | |
typename impl2::expr_param e | |
, typename impl2::state_param s | |
, typename impl2::data_param d | |
) const | |
{ | |
return typename detail::poly_function_traits<Fun, Fun(a0, a1, a2)>::function_type()( | |
detail::as_lvalue(typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d)) | |
, detail::as_lvalue(typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d)) | |
, detail::as_lvalue(typename when<_, A2>::template impl<Expr, State, Data>()(e, s, d)) | |
); | |
} | |
}; | |
template<typename Expr, typename State, typename Data> | |
struct impl2<Expr, State, Data, true> | |
: transform_impl<Expr, State, Data> | |
{ | |
typedef typename when<_, A0>::template impl<Expr, State, Data>::result_type a0; | |
typedef typename when<_, A1>::template impl<Expr, State, Data>::result_type a1; | |
typedef typename when<_, A2>::template impl<Expr, State, Data>::result_type a2; | |
typedef typename Fun::template impl<a0, a1, a2>::result_type result_type; | |
result_type operator ()( | |
typename impl2::expr_param e | |
, typename impl2::state_param s | |
, typename impl2::data_param d | |
) const | |
{ | |
return typename Fun::template impl<a0, a1, a2>()( | |
typename when<_, A0>::template impl<Expr, State, Data>()(e, s, d) | |
, typename when<_, A1>::template impl<Expr, State, Data>()(e, s, d) | |
, typename when<_, A2>::template impl<Expr, State, Data>()(e, s, d) | |
); | |
} | |
}; | |
/// Let \c x be <tt>when\<_, A0\>()(e, s, d)</tt>. | |
/// Let \c y be <tt>when\<_, A1\>()(e, s, d)</tt>. | |
/// Let \c z be <tt>when\<_, A2\>()(e, s, d)</tt>. | |
/// Return <tt>Fun()(x, y, z)</tt>. | |
/// | |
/// \param e The current expression | |
/// \param s The current state | |
/// \param d An arbitrary data | |
template<typename Expr, typename State, typename Data> | |
struct impl | |
: impl2<Expr, State, Data, is_transform<Fun>::value> | |
{}; | |
}; | |
#if BOOST_PROTO_MAX_ARITY > 3 | |
#define BOOST_PP_ITERATION_PARAMS_1 (3, (4, BOOST_PROTO_MAX_ARITY, <boost/proto/transform/call.hpp>)) | |
#include BOOST_PP_ITERATE() | |
#endif | |
/// INTERNAL ONLY | |
/// | |
template<typename Fun> | |
struct is_callable<call<Fun> > | |
: mpl::true_ | |
{}; | |
}} // namespace boost::proto | |
#endif | |
#else | |
#define N BOOST_PP_ITERATION() | |
/// \brief Call the PolymorphicFunctionObject \c Fun with the | |
/// current expression, state and data, transformed according | |
/// to \c A0 through \c AN. | |
template<typename Fun BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)> | |
struct call<Fun(BOOST_PP_ENUM_PARAMS(N, A))> : transform<call<Fun(BOOST_PP_ENUM_PARAMS(N, A))> > | |
{ | |
template<typename Expr, typename State, typename Data> | |
struct impl : transform_impl<Expr, State, Data> | |
{ | |
#define M0(Z, M, DATA) \ | |
typedef \ | |
typename when<_, BOOST_PP_CAT(A, M)> \ | |
::template impl<Expr, State, Data> \ | |
::result_type \ | |
BOOST_PP_CAT(a, M); \ | |
/**/ | |
BOOST_PP_REPEAT(N, M0, ~) | |
#undef M0 | |
typedef | |
typename detail::poly_function_traits<Fun, Fun(BOOST_PP_ENUM_PARAMS(N, a))>::result_type | |
result_type; | |
/// Let \c ax be <tt>when\<_, Ax\>()(e, s, d)</tt> | |
/// for each \c x in <tt>[0,N]</tt>. | |
/// Return <tt>Fun()(a0, a1,... aN)</tt>. | |
/// | |
/// \param e The current expression | |
/// \param s The current state | |
/// \param d An arbitrary data | |
result_type operator ()( | |
typename impl::expr_param e | |
, typename impl::state_param s | |
, typename impl::data_param d | |
) const | |
{ | |
#define M0(Z, M, DATA) \ | |
detail::as_lvalue( \ | |
typename when<_, BOOST_PP_CAT(A, M)> \ | |
::template impl<Expr, State, Data>()(e, s, d)) \ | |
/**/ | |
return typename detail::poly_function_traits<Fun, Fun(BOOST_PP_ENUM_PARAMS(N, a))>::function_type()( | |
BOOST_PP_ENUM(N, M0, ~) | |
); | |
#undef M0 | |
} | |
}; | |
}; | |
#undef N | |
#endif |