Chris@16: /*=============================================================================
Chris@16:     Copyright (c) 1998-2003 Joel de Guzman
Chris@16:     Copyright (c) 2002 Raghavendra Satish
Chris@16:     Copyright (c) 2002 Jeff Westfahl
Chris@16:     http://spirit.sourceforge.net/
Chris@16: 
Chris@16:   Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: =============================================================================*/
Chris@16: #if !defined(BOOST_SPIRIT_LOOPS_HPP)
Chris@16: #define BOOST_SPIRIT_LOOPS_HPP
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: #include <boost/spirit/home/classic/namespace.hpp>
Chris@16: #include <boost/spirit/home/classic/core/parser.hpp>
Chris@16: #include <boost/spirit/home/classic/core/composite/composite.hpp>
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: namespace boost { namespace spirit {
Chris@16: 
Chris@16: BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     //
Chris@16:     //  fixed_loop class
Chris@16:     //
Chris@16:     //      This class takes care of the construct:
Chris@16:     //
Chris@16:     //          repeat_p (exact) [p]
Chris@16:     //
Chris@16:     //      where 'p' is a parser and 'exact' is the number of times to
Chris@16:     //      repeat. The parser iterates over the input exactly 'exact' times.
Chris@16:     //      The parse function fails if the parser does not match the input
Chris@16:     //      exactly 'exact' times.
Chris@16:     //
Chris@16:     //      This class is parametizable and can accept constant arguments
Chris@16:     //      (e.g. repeat_p (5) [p]) as well as references to variables (e.g.
Chris@16:     //      repeat_p (ref (n)) [p]).
Chris@16:     //
Chris@16:     ///////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename ParserT, typename ExactT>
Chris@16:     class fixed_loop
Chris@16:     : public unary<ParserT, parser <fixed_loop <ParserT, ExactT> > >
Chris@16:     {
Chris@16:     public:
Chris@16: 
Chris@16:         typedef fixed_loop<ParserT, ExactT>     self_t;
Chris@16:         typedef unary<ParserT, parser<self_t> >  base_t;
Chris@16: 
Chris@16:         fixed_loop (ParserT const & subject_, ExactT const & exact)
Chris@16:         : base_t(subject_), m_exact(exact) {}
Chris@16: 
Chris@16:         template <typename ScannerT>
Chris@16:         typename parser_result <self_t, ScannerT>::type
Chris@16:         parse (ScannerT const & scan) const
Chris@16:         {
Chris@16:             typedef typename parser_result<self_t, ScannerT>::type result_t;
Chris@16:             result_t hit = scan.empty_match();
Chris@16:             std::size_t n = m_exact;
Chris@16: 
Chris@16:             for (std::size_t i = 0; i < n; ++i)
Chris@16:             {
Chris@16:                 if (result_t next = this->subject().parse(scan))
Chris@16:                 {
Chris@16:                     scan.concat_match(hit, next);
Chris@16:                 }
Chris@16:                 else
Chris@16:                 {
Chris@16:                     return scan.no_match();
Chris@16:                 }
Chris@16:             }
Chris@16: 
Chris@16:             return hit;
Chris@16:         }
Chris@16: 
Chris@16:         template <typename ScannerT>
Chris@16:         struct result
Chris@16:         {
Chris@16:             typedef typename match_result<ScannerT, nil_t>::type type;
Chris@16:         };
Chris@16: 
Chris@16:     private:
Chris@16: 
Chris@16:         ExactT m_exact;
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     //
Chris@16:     //  finite_loop class
Chris@16:     //
Chris@16:     //      This class takes care of the construct:
Chris@16:     //
Chris@16:     //          repeat_p (min, max) [p]
Chris@16:     //
Chris@16:     //      where 'p' is a parser, 'min' and 'max' specifies the minimum and
Chris@16:     //      maximum iterations over 'p'. The parser iterates over the input
Chris@16:     //      at least 'min' times and at most 'max' times. The parse function
Chris@16:     //      fails if the parser does not match the input at least 'min' times
Chris@16:     //      and at most 'max' times.
Chris@16:     //
Chris@16:     //      This class is parametizable and can accept constant arguments
Chris@16:     //      (e.g. repeat_p (5, 10) [p]) as well as references to variables
Chris@16:     //      (e.g. repeat_p (ref (n1), ref (n2)) [p]).
Chris@16:     //
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     template <typename ParserT, typename MinT, typename MaxT>
Chris@16:     class finite_loop
Chris@16:     : public unary<ParserT, parser<finite_loop<ParserT, MinT, MaxT> > >
Chris@16:     {
Chris@16:     public:
Chris@16: 
Chris@16:         typedef finite_loop <ParserT, MinT, MaxT> self_t;
Chris@16:         typedef unary<ParserT, parser<self_t> >   base_t;
Chris@16: 
Chris@16:         finite_loop (ParserT const & subject_, MinT const & min, MaxT const & max)
Chris@16:         : base_t(subject_), m_min(min), m_max(max) {}
Chris@16: 
Chris@16:         template <typename ScannerT>
Chris@16:         typename parser_result <self_t, ScannerT>::type
Chris@16:         parse(ScannerT const & scan) const
Chris@16:         {
Chris@16:             BOOST_SPIRIT_ASSERT(m_min <= m_max);
Chris@16:             typedef typename parser_result<self_t, ScannerT>::type result_t;
Chris@16:             result_t hit = scan.empty_match();
Chris@16: 
Chris@16:             std::size_t n1 = m_min;
Chris@16:             std::size_t n2 = m_max;
Chris@16: 
Chris@16:             for (std::size_t i = 0; i < n2; ++i)
Chris@16:             {
Chris@16:                 typename ScannerT::iterator_t save = scan.first;
Chris@16:                 result_t next = this->subject().parse(scan);
Chris@16:  
Chris@16:                 if (!next)
Chris@16:                 {
Chris@16:                     if (i >= n1)
Chris@16:                     {
Chris@16:                         scan.first = save;
Chris@16:                         break;
Chris@16:                     }
Chris@16:                     else
Chris@16:                     {
Chris@16:                         return scan.no_match();
Chris@16:                     }
Chris@16:                 }
Chris@16: 
Chris@16:                 scan.concat_match(hit, next);
Chris@16:             }
Chris@16: 
Chris@16:             return hit;
Chris@16:         }
Chris@16: 
Chris@16:         template <typename ScannerT>
Chris@16:         struct result
Chris@16:         {
Chris@16:             typedef typename match_result<ScannerT, nil_t>::type type;
Chris@16:         };
Chris@16: 
Chris@16:     private:
Chris@16: 
Chris@16:         MinT    m_min;
Chris@16:         MaxT    m_max;
Chris@16:     };
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     //
Chris@16:     //  infinite_loop class
Chris@16:     //
Chris@16:     //      This class takes care of the construct:
Chris@16:     //
Chris@16:     //          repeat_p (min, more) [p]
Chris@16:     //
Chris@16:     //      where 'p' is a parser, 'min' is the minimum iteration over 'p'
Chris@16:     //      and more specifies that the iteration should proceed
Chris@16:     //      indefinitely. The parser iterates over the input at least 'min'
Chris@16:     //      times and continues indefinitely until 'p' fails or all of the
Chris@16:     //      input is parsed. The parse function fails if the parser does not
Chris@16:     //      match the input at least 'min' times.
Chris@16:     //
Chris@16:     //      This class is parametizable and can accept constant arguments
Chris@16:     //      (e.g. repeat_p (5, more) [p]) as well as references to variables
Chris@16:     //      (e.g. repeat_p (ref (n), more) [p]).
Chris@16:     //
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16:     struct more_t {};
Chris@16:     more_t const more = more_t ();
Chris@16: 
Chris@16:     template <typename ParserT, typename MinT>
Chris@16:     class infinite_loop
Chris@16:      : public unary<ParserT, parser<infinite_loop<ParserT, MinT> > >
Chris@16:     {
Chris@16:     public:
Chris@16: 
Chris@16:         typedef infinite_loop <ParserT, MinT>   self_t;
Chris@16:         typedef unary<ParserT, parser<self_t> > base_t;
Chris@16: 
Chris@16:         infinite_loop (
Chris@16:             ParserT const& subject_,
Chris@16:             MinT const& min,
Chris@16:             more_t const&
Chris@16:         )
Chris@16:         : base_t(subject_), m_min(min) {}
Chris@16: 
Chris@16:         template <typename ScannerT>
Chris@16:         typename parser_result <self_t, ScannerT>::type
Chris@16:         parse(ScannerT const & scan) const
Chris@16:         {
Chris@16:             typedef typename parser_result<self_t, ScannerT>::type result_t;
Chris@16:             result_t hit = scan.empty_match();
Chris@16:             std::size_t n = m_min;
Chris@16: 
Chris@16:             for (std::size_t i = 0; ; ++i)
Chris@16:             {
Chris@16:                 typename ScannerT::iterator_t save = scan.first;
Chris@16:                 result_t next = this->subject().parse(scan);
Chris@16: 
Chris@16:                 if (!next)
Chris@16:                 {
Chris@16:                     if (i >= n)
Chris@16:                     {
Chris@16:                         scan.first = save;
Chris@16:                         break;
Chris@16:                     }
Chris@16:                     else
Chris@16:                     {
Chris@16:                         return scan.no_match();
Chris@16:                     }
Chris@16:                 }
Chris@16: 
Chris@16:                 scan.concat_match(hit, next);
Chris@16:             }
Chris@16: 
Chris@16:             return hit;
Chris@16:         }
Chris@16: 
Chris@16:         template <typename ScannerT>
Chris@16:         struct result
Chris@16:         {
Chris@16:             typedef typename match_result<ScannerT, nil_t>::type type;
Chris@16:         };
Chris@16: 
Chris@16:         private:
Chris@16: 
Chris@16:         MinT m_min;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename ExactT>
Chris@16:     struct fixed_loop_gen
Chris@16:     {
Chris@16:         fixed_loop_gen (ExactT const & exact)
Chris@16:         : m_exact (exact) {}
Chris@16: 
Chris@16:         template <typename ParserT>
Chris@16:         fixed_loop <ParserT, ExactT>
Chris@16:         operator[](parser <ParserT> const & subject_) const
Chris@16:         {
Chris@16:             return fixed_loop <ParserT, ExactT> (subject_.derived (), m_exact);
Chris@16:         }
Chris@16: 
Chris@16:         ExactT m_exact;
Chris@16:     };
Chris@16: 
Chris@16:     namespace impl {
Chris@16: 
Chris@16:         template <typename ParserT, typename MinT, typename MaxT>
Chris@16:         struct loop_traits
Chris@16:         {
Chris@16:             typedef typename mpl::if_<
Chris@16:                 boost::is_same<MaxT, more_t>,
Chris@16:                 infinite_loop<ParserT, MinT>,
Chris@16:                 finite_loop<ParserT, MinT, MaxT>
Chris@16:             >::type type;
Chris@16:         };
Chris@16: 
Chris@16:     } // namespace impl
Chris@16: 
Chris@16:     template <typename MinT, typename MaxT>
Chris@16:     struct nonfixed_loop_gen
Chris@16:     {
Chris@16:        nonfixed_loop_gen (MinT min, MaxT max)
Chris@16:         : m_min (min), m_max (max) {}
Chris@16: 
Chris@16:        template <typename ParserT>
Chris@16:        typename impl::loop_traits<ParserT, MinT, MaxT>::type
Chris@16:        operator[](parser <ParserT> const & subject_) const
Chris@16:        {
Chris@16:            typedef typename impl::loop_traits<ParserT, MinT, MaxT>::type ret_t;
Chris@16:            return ret_t(
Chris@16:                 subject_.derived(),
Chris@16:                 m_min,
Chris@16:                 m_max);
Chris@16:        }
Chris@16: 
Chris@16:        MinT m_min;
Chris@16:        MaxT m_max;
Chris@16:     };
Chris@16: 
Chris@16:     template <typename ExactT>
Chris@16:     fixed_loop_gen <ExactT>
Chris@16:     repeat_p(ExactT const & exact)
Chris@16:     {
Chris@16:         return fixed_loop_gen <ExactT> (exact);
Chris@16:     }
Chris@16: 
Chris@16:     template <typename MinT, typename MaxT>
Chris@16:     nonfixed_loop_gen <MinT, MaxT>
Chris@16:     repeat_p(MinT const & min, MaxT const & max)
Chris@16:     {
Chris@16:         return nonfixed_loop_gen <MinT, MaxT> (min, max);
Chris@16:     }
Chris@16: 
Chris@16: BOOST_SPIRIT_CLASSIC_NAMESPACE_END
Chris@16: 
Chris@16: }} // namespace BOOST_SPIRIT_CLASSIC_NS
Chris@16: 
Chris@16: #endif // #if !defined(BOOST_SPIRIT_LOOPS_HPP)