Sprout/sprout/breed/transform/pass_through.hpp
2012-05-22 01:06:13 +09:00

128 lines
3.7 KiB
C++

#ifndef SPROUT_BREED_TRANSFORM_PASS_THROUGH_HPP
#define SPROUT_BREED_TRANSFORM_PASS_THROUGH_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/index_tuple.hpp>
#include <sprout/breed/breed_fwd.hpp>
#include <sprout/breed/args.hpp>
#include <sprout/breed/transform/impl.hpp>
#include <sprout/breed/detail/std_result_of.hpp>
namespace sprout {
namespace breed {
namespace detail {
template<
typename Grammar,
typename Expr,
typename State,
typename Data,
long Arity = sprout::breed::arity_of<Expr>::value
>
struct pass_through_impl
: public sprout::breed::transform_impl<Expr, State, Data>
{
public:
typedef typename pass_through_impl::expr unref_expr;
private:
template<typename IndexTuple>
struct list_impl {};
template<sprout::index_t... Indexes>
struct list_impl<sprout::index_tuple<Indexes...> > {
public:
typedef sprout::breed::list<
typename Grammar::template breed_child<Indexes>::type::template impl<
typename sprout::breed::result_of::child_c<Expr, Indexes>::type,
State,
Data
>::result_type...
> type;
};
public:
typedef typename sprout::breed::base_expr<
typename unref_expr::breed_domain,
typename unref_expr::breed_tag,
typename list_impl<typename sprout::index_range<0, Arity>::type>::type
>::type expr_type;
typedef typename unref_expr::breed_generator breed_generator;
typedef typename sprout::breed::detail::std_result_of<
breed_generator(expr_type)
>::type result_type;
private:
template<sprout::index_t... Indexes>
SPROUT_CONSTEXPR result_type call_impl(
typename pass_through_impl::expr_param e,
typename pass_through_impl::state_param s,
typename pass_through_impl::data_param d,
sprout::index_tuple<Indexes...>
) const
{
return breed_generator()(
expr_type(
typename Grammar::template breed_child<Indexes>::type::template impl<
typename sprout::breed::result_of::child_c<Expr, Indexes>::type,
State,
Data
>()(e.proto_base().template child<Indexes>(), s, d)...
)
);
}
public:
SPROUT_CONSTEXPR result_type operator()(
typename pass_through_impl::expr_param e,
typename pass_through_impl::state_param s,
typename pass_through_impl::data_param d
) const
{
return call_impl(e, s, d, sprout::index_range<0, Arity>::make());
}
};
template<typename Grammar, typename Expr, typename State, typename Data>
struct pass_through_impl<Grammar, Expr, State, Data, 0>
: public sprout::breed::transform_impl<Expr, State, Data>
{
public:
typedef Expr result_type;
public:
#ifdef SPROUT_BREED_STRICT_RESULT_OF
SPROUT_CONSTEXPR result_type
#else
SPROUT_CONSTEXPR typename pass_through_impl::expr_param
#endif
operator()(
typename pass_through_impl::expr_param e,
typename pass_through_impl::state_param,
typename pass_through_impl::data_param
) const
{
return e;
}
};
} // namespace detail
//
// pass_through
//
template<typename Grammar>
struct pass_through
: public sprout::breed::transform<sprout::breed::pass_through<Grammar> >
{
public:
template<typename Expr, typename State, typename Data>
struct impl
: public sprout::breed::detail::pass_through_impl<Grammar, Expr, State, Data>
{};
};
//
// is_callable
//
template<typename Grammar>
struct is_callable<sprout::breed::pass_through<Grammar> >
: public std::true_type
{};
} // namespace breed
} // namespace sprout
#endif // #ifndef SPROUT_BREED_TRANSFORM_PASS_THROUGH_HPP