66 lines
1.9 KiB
C++
66 lines
1.9 KiB
C++
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#ifndef BOOST_METAPARSE_V1_FOLDL_HPP
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#define BOOST_METAPARSE_V1_FOLDL_HPP
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// Copyright Abel Sinkovics (abel@sinkovics.hu) 2011.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <boost/metaparse/v1/accept.hpp>
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#include <boost/metaparse/v1/is_error.hpp>
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#include <boost/metaparse/v1/get_position.hpp>
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#include <boost/metaparse/v1/get_result.hpp>
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#include <boost/metaparse/v1/get_remaining.hpp>
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#include <boost/mpl/eval_if.hpp>
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namespace boost
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{
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namespace metaparse
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{
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namespace v1
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{
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template <class P, class State, class ForwardOp>
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struct foldl
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{
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private:
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template <class Res>
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struct apply_unchecked :
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// foldl never returns error
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// I need to use apply_wrap, and not apply, because apply would
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// build a metafunction class from foldl<P, State, ForwardOp>
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// when ForwardOp is a lambda expression.
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foldl<
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P,
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typename ForwardOp::template apply<
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typename State::type,
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typename get_result<Res>::type
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>,
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ForwardOp
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>::template apply<
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typename get_remaining<Res>::type,
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typename get_position<Res>::type
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>
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{};
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template <class S, class Pos>
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struct next_iteration : accept<typename State::type, S, Pos> {};
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public:
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typedef foldl type;
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template <class S, class Pos>
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struct apply :
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boost::mpl::eval_if<
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typename is_error<typename P::template apply<S, Pos> >::type,
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next_iteration<S, Pos>,
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apply_unchecked<typename P::template apply<S, Pos> >
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>
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{};
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};
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}
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}
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}
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#endif
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