80 lines
3.0 KiB
Plaintext
80 lines
3.0 KiB
Plaintext
#if !defined(BOOST_PROTO_DONT_USE_PREPROCESSED_FILES)
|
|
|
|
#include <boost/proto/transform/detail/preprocessed/lazy.hpp>
|
|
|
|
#elif !defined(BOOST_PP_IS_ITERATING)
|
|
|
|
#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
|
|
#pragma wave option(preserve: 2, line: 0, output: "preprocessed/lazy.hpp")
|
|
#endif
|
|
|
|
///////////////////////////////////////////////////////////////////////////////
|
|
/// \file lazy.hpp
|
|
/// Contains definition of the lazy<> 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)
|
|
|
|
#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/transform/detail/lazy.hpp>))
|
|
#include BOOST_PP_ITERATE()
|
|
|
|
#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
|
|
#pragma wave option(output: null)
|
|
#endif
|
|
|
|
#else
|
|
|
|
#define N BOOST_PP_ITERATION()
|
|
|
|
/// \brief A PrimitiveTransform that uses <tt>make\<\></tt> to build
|
|
/// a CallableTransform, and then uses <tt>call\<\></tt> to apply it.
|
|
///
|
|
/// <tt>lazy\<\></tt> is useful as a higher-order transform, when the
|
|
/// transform to be applied depends on the current state of the
|
|
/// transformation. The invocation of the <tt>make\<\></tt> transform
|
|
/// evaluates any nested transforms, and the resulting type is treated
|
|
/// as a CallableTransform, which is evaluated with <tt>call\<\></tt>.
|
|
template<typename Object BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
|
|
struct lazy<Object(BOOST_PP_ENUM_PARAMS(N, A))>
|
|
: transform<lazy<Object(BOOST_PP_ENUM_PARAMS(N, A))> >
|
|
{
|
|
template<typename Expr, typename State, typename Data>
|
|
struct impl
|
|
: call<
|
|
typename make<Object>::template impl<Expr, State, Data>::result_type
|
|
(BOOST_PP_ENUM_PARAMS(N, A))
|
|
>::template impl<Expr, State, Data>
|
|
{};
|
|
};
|
|
|
|
#if N > 0
|
|
template<typename Object BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
|
|
struct lazy<Object(BOOST_PP_ENUM_PARAMS(N, A)...)>
|
|
: transform<lazy<Object(BOOST_PP_ENUM_PARAMS(N, A)...)> >
|
|
{
|
|
template<typename Expr, typename State, typename Data>
|
|
struct impl
|
|
: lazy<
|
|
typename detail::expand_pattern<
|
|
proto::arity_of<Expr>::value
|
|
, BOOST_PP_CAT(A, BOOST_PP_DEC(N))
|
|
, detail::BOOST_PP_CAT(expand_pattern_rest_, BOOST_PP_DEC(N))<
|
|
Object
|
|
BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_DEC(N), A)
|
|
>
|
|
>::type
|
|
>::template impl<Expr, State, Data>
|
|
{};
|
|
};
|
|
#endif
|
|
|
|
#undef N
|
|
|
|
#endif
|