80 lines
3.0 KiB
Plaintext
80 lines
3.0 KiB
Plaintext
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#if !defined(BOOST_PROTO_DONT_USE_PREPROCESSED_FILES)
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#include <boost/proto/transform/detail/preprocessed/lazy.hpp>
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#elif !defined(BOOST_PP_IS_ITERATING)
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#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
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#pragma wave option(preserve: 2, line: 0, output: "preprocessed/lazy.hpp")
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#endif
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///////////////////////////////////////////////////////////////////////////////
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/// \file lazy.hpp
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/// Contains definition of the lazy<> transform.
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//
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// Copyright 2008 Eric Niebler. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
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#pragma wave option(preserve: 1)
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#endif
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#define BOOST_PP_ITERATION_PARAMS_1 \
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(3, (0, BOOST_PROTO_MAX_ARITY, <boost/proto/transform/detail/lazy.hpp>))
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#include BOOST_PP_ITERATE()
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#if defined(__WAVE__) && defined(BOOST_PROTO_CREATE_PREPROCESSED_FILES)
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#pragma wave option(output: null)
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#endif
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#else
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#define N BOOST_PP_ITERATION()
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/// \brief A PrimitiveTransform that uses <tt>make\<\></tt> to build
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/// a CallableTransform, and then uses <tt>call\<\></tt> to apply it.
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///
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/// <tt>lazy\<\></tt> is useful as a higher-order transform, when the
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/// transform to be applied depends on the current state of the
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/// transformation. The invocation of the <tt>make\<\></tt> transform
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/// evaluates any nested transforms, and the resulting type is treated
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/// as a CallableTransform, which is evaluated with <tt>call\<\></tt>.
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template<typename Object BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
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struct lazy<Object(BOOST_PP_ENUM_PARAMS(N, A))>
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: transform<lazy<Object(BOOST_PP_ENUM_PARAMS(N, A))> >
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{
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template<typename Expr, typename State, typename Data>
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struct impl
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: call<
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typename make<Object>::template impl<Expr, State, Data>::result_type
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(BOOST_PP_ENUM_PARAMS(N, A))
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>::template impl<Expr, State, Data>
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{};
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};
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#if N > 0
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template<typename Object BOOST_PP_ENUM_TRAILING_PARAMS(N, typename A)>
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struct lazy<Object(BOOST_PP_ENUM_PARAMS(N, A)...)>
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: transform<lazy<Object(BOOST_PP_ENUM_PARAMS(N, A)...)> >
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{
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template<typename Expr, typename State, typename Data>
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struct impl
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: lazy<
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typename detail::expand_pattern<
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proto::arity_of<Expr>::value
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, BOOST_PP_CAT(A, BOOST_PP_DEC(N))
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, detail::BOOST_PP_CAT(expand_pattern_rest_, BOOST_PP_DEC(N))<
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Object
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BOOST_PP_ENUM_TRAILING_PARAMS(BOOST_PP_DEC(N), A)
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>
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>::type
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>::template impl<Expr, State, Data>
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{};
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};
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#endif
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#undef N
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#endif
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