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- #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
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