320 lines
9.7 KiB
C++
320 lines
9.7 KiB
C++
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/*=============================================================================
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Copyright (c) 1998-2003 Joel de Guzman
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Copyright (c) 2002 Raghavendra Satish
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Copyright (c) 2002 Jeff Westfahl
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http://spirit.sourceforge.net/
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#if !defined(BOOST_SPIRIT_LOOPS_HPP)
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#define BOOST_SPIRIT_LOOPS_HPP
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///////////////////////////////////////////////////////////////////////////////
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#include <boost/spirit/home/classic/namespace.hpp>
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#include <boost/spirit/home/classic/core/parser.hpp>
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#include <boost/spirit/home/classic/core/composite/composite.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/type_traits/is_same.hpp>
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///////////////////////////////////////////////////////////////////////////////
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namespace boost { namespace spirit {
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BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
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///////////////////////////////////////////////////////////////////////////
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//
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// fixed_loop class
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//
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// This class takes care of the construct:
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//
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// repeat_p (exact) [p]
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//
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// where 'p' is a parser and 'exact' is the number of times to
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// repeat. The parser iterates over the input exactly 'exact' times.
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// The parse function fails if the parser does not match the input
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// exactly 'exact' times.
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//
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// This class is parametizable and can accept constant arguments
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// (e.g. repeat_p (5) [p]) as well as references to variables (e.g.
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// repeat_p (ref (n)) [p]).
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//
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///////////////////////////////////////////////////////////////////////////
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template <typename ParserT, typename ExactT>
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class fixed_loop
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: public unary<ParserT, parser <fixed_loop <ParserT, ExactT> > >
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{
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public:
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typedef fixed_loop<ParserT, ExactT> self_t;
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typedef unary<ParserT, parser<self_t> > base_t;
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fixed_loop (ParserT const & subject_, ExactT const & exact)
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: base_t(subject_), m_exact(exact) {}
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template <typename ScannerT>
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typename parser_result <self_t, ScannerT>::type
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parse (ScannerT const & scan) const
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{
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typedef typename parser_result<self_t, ScannerT>::type result_t;
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result_t hit = scan.empty_match();
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std::size_t n = m_exact;
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for (std::size_t i = 0; i < n; ++i)
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{
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if (result_t next = this->subject().parse(scan))
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{
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scan.concat_match(hit, next);
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}
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else
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{
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return scan.no_match();
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}
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}
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return hit;
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}
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template <typename ScannerT>
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struct result
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{
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typedef typename match_result<ScannerT, nil_t>::type type;
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};
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private:
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ExactT m_exact;
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};
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///////////////////////////////////////////////////////////////////////////////
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//
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// finite_loop class
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//
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// This class takes care of the construct:
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//
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// repeat_p (min, max) [p]
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//
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// where 'p' is a parser, 'min' and 'max' specifies the minimum and
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// maximum iterations over 'p'. The parser iterates over the input
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// at least 'min' times and at most 'max' times. The parse function
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// fails if the parser does not match the input at least 'min' times
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// and at most 'max' times.
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//
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// This class is parametizable and can accept constant arguments
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// (e.g. repeat_p (5, 10) [p]) as well as references to variables
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// (e.g. repeat_p (ref (n1), ref (n2)) [p]).
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//
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///////////////////////////////////////////////////////////////////////////////
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template <typename ParserT, typename MinT, typename MaxT>
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class finite_loop
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: public unary<ParserT, parser<finite_loop<ParserT, MinT, MaxT> > >
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{
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public:
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typedef finite_loop <ParserT, MinT, MaxT> self_t;
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typedef unary<ParserT, parser<self_t> > base_t;
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finite_loop (ParserT const & subject_, MinT const & min, MaxT const & max)
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: base_t(subject_), m_min(min), m_max(max) {}
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template <typename ScannerT>
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typename parser_result <self_t, ScannerT>::type
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parse(ScannerT const & scan) const
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{
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BOOST_SPIRIT_ASSERT(m_min <= m_max);
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typedef typename parser_result<self_t, ScannerT>::type result_t;
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result_t hit = scan.empty_match();
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std::size_t n1 = m_min;
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std::size_t n2 = m_max;
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for (std::size_t i = 0; i < n2; ++i)
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{
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typename ScannerT::iterator_t save = scan.first;
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result_t next = this->subject().parse(scan);
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if (!next)
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{
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if (i >= n1)
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{
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scan.first = save;
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break;
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}
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else
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{
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return scan.no_match();
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}
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}
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scan.concat_match(hit, next);
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}
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return hit;
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}
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template <typename ScannerT>
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struct result
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{
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typedef typename match_result<ScannerT, nil_t>::type type;
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};
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private:
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MinT m_min;
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MaxT m_max;
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};
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///////////////////////////////////////////////////////////////////////////////
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//
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// infinite_loop class
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//
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// This class takes care of the construct:
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//
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// repeat_p (min, more) [p]
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//
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// where 'p' is a parser, 'min' is the minimum iteration over 'p'
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// and more specifies that the iteration should proceed
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// indefinitely. The parser iterates over the input at least 'min'
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// times and continues indefinitely until 'p' fails or all of the
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// input is parsed. The parse function fails if the parser does not
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// match the input at least 'min' times.
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//
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// This class is parametizable and can accept constant arguments
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// (e.g. repeat_p (5, more) [p]) as well as references to variables
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// (e.g. repeat_p (ref (n), more) [p]).
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//
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///////////////////////////////////////////////////////////////////////////////
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struct more_t {};
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more_t const more = more_t ();
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template <typename ParserT, typename MinT>
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class infinite_loop
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: public unary<ParserT, parser<infinite_loop<ParserT, MinT> > >
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{
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public:
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typedef infinite_loop <ParserT, MinT> self_t;
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typedef unary<ParserT, parser<self_t> > base_t;
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infinite_loop (
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ParserT const& subject_,
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MinT const& min,
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more_t const&
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)
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: base_t(subject_), m_min(min) {}
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template <typename ScannerT>
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typename parser_result <self_t, ScannerT>::type
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parse(ScannerT const & scan) const
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{
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typedef typename parser_result<self_t, ScannerT>::type result_t;
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result_t hit = scan.empty_match();
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std::size_t n = m_min;
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for (std::size_t i = 0; ; ++i)
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{
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typename ScannerT::iterator_t save = scan.first;
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result_t next = this->subject().parse(scan);
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if (!next)
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{
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if (i >= n)
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{
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scan.first = save;
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break;
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}
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else
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{
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return scan.no_match();
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}
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}
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scan.concat_match(hit, next);
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}
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return hit;
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}
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template <typename ScannerT>
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struct result
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{
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typedef typename match_result<ScannerT, nil_t>::type type;
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};
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private:
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MinT m_min;
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};
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template <typename ExactT>
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struct fixed_loop_gen
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{
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fixed_loop_gen (ExactT const & exact)
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: m_exact (exact) {}
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template <typename ParserT>
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fixed_loop <ParserT, ExactT>
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operator[](parser <ParserT> const & subject_) const
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{
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return fixed_loop <ParserT, ExactT> (subject_.derived (), m_exact);
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}
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ExactT m_exact;
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};
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namespace impl {
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template <typename ParserT, typename MinT, typename MaxT>
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struct loop_traits
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{
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typedef typename mpl::if_<
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boost::is_same<MaxT, more_t>,
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infinite_loop<ParserT, MinT>,
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finite_loop<ParserT, MinT, MaxT>
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>::type type;
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};
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} // namespace impl
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template <typename MinT, typename MaxT>
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struct nonfixed_loop_gen
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{
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nonfixed_loop_gen (MinT min, MaxT max)
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: m_min (min), m_max (max) {}
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template <typename ParserT>
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typename impl::loop_traits<ParserT, MinT, MaxT>::type
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operator[](parser <ParserT> const & subject_) const
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{
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typedef typename impl::loop_traits<ParserT, MinT, MaxT>::type ret_t;
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return ret_t(
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subject_.derived(),
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m_min,
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m_max);
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}
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MinT m_min;
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MaxT m_max;
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};
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template <typename ExactT>
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fixed_loop_gen <ExactT>
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repeat_p(ExactT const & exact)
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{
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return fixed_loop_gen <ExactT> (exact);
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}
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template <typename MinT, typename MaxT>
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nonfixed_loop_gen <MinT, MaxT>
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repeat_p(MinT const & min, MaxT const & max)
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{
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return nonfixed_loop_gen <MinT, MaxT> (min, max);
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}
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BOOST_SPIRIT_CLASSIC_NAMESPACE_END
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}} // namespace BOOST_SPIRIT_CLASSIC_NS
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#endif // #if !defined(BOOST_SPIRIT_LOOPS_HPP)
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