/*=============================================================================
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Copyright (c) 2002-2003 Hartmut Kaiser
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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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#ifndef BOOST_SPIRIT_CONFIX_HPP
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#define BOOST_SPIRIT_CONFIX_HPP
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///////////////////////////////////////////////////////////////////////////////
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#include <boost/config.hpp>
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#include <boost/spirit/home/classic/namespace.hpp>
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#include <boost/spirit/home/classic/meta/as_parser.hpp>
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#include <boost/spirit/home/classic/core/composite/operators.hpp>
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#include <boost/spirit/home/classic/utility/confix_fwd.hpp>
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#include <boost/spirit/home/classic/utility/impl/confix.ipp>
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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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// confix_parser class
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//
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// Parses a sequence of 3 sub-matches. This class may
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// be used to parse structures, where the opening part is possibly
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// contained in the expression part and the whole sequence is only
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// parsed after seeing the closing part matching the first opening
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// subsequence. Example: C-comments:
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//
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// /* This is a C-comment */
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//
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///////////////////////////////////////////////////////////////////////////////
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#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
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#pragma warning(push)
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#pragma warning(disable:4512) //assignment operator could not be generated
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#endif
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template<typename NestedT = non_nested, typename LexemeT = non_lexeme>
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struct confix_parser_gen;
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template <
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typename OpenT, typename ExprT, typename CloseT, typename CategoryT,
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typename NestedT, typename LexemeT
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>
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struct confix_parser :
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public parser<
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confix_parser<OpenT, ExprT, CloseT, CategoryT, NestedT, LexemeT>
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>
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{
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typedef
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confix_parser<OpenT, ExprT, CloseT, CategoryT, NestedT, LexemeT>
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self_t;
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confix_parser(OpenT const &open_, ExprT const &expr_, CloseT const &close_)
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: open(open_), expr(expr_), close(close_)
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{}
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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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return impl::confix_parser_type<CategoryT>::
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parse(NestedT(), LexemeT(), *this, scan, open, expr, close);
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}
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private:
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typename as_parser<OpenT>::type::embed_t open;
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typename as_parser<ExprT>::type::embed_t expr;
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typename as_parser<CloseT>::type::embed_t close;
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};
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#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
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#pragma warning(pop)
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#endif
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///////////////////////////////////////////////////////////////////////////////
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//
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// Confix parser generator template
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//
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// This is a helper for generating a correct confix_parser<> from
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// auxiliary parameters. There are the following types supported as
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// parameters yet: parsers, single characters and strings (see
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// as_parser).
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//
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// If the body parser is an action_parser_category type parser (a parser
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// with an attached semantic action) we have to do something special. This
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// happens, if the user wrote something like:
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//
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// confix_p(open, body[f], close)
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//
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// where 'body' is the parser matching the body of the confix sequence
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// and 'f' is a functor to be called after matching the body. If we would
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// do nothing, the resulting code would parse the sequence as follows:
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//
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// start >> (body[f] - close) >> close
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//
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// what in most cases is not what the user expects.
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// (If this _is_ what you've expected, then please use the confix_p
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// generator function 'direct()', which will inhibit
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// re-attaching the actor to the body parser).
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//
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// To make the confix parser behave as expected:
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//
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// start >> (body - close)[f] >> close
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//
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// the actor attached to the 'body' parser has to be re-attached to the
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// (body - close) parser construct, which will make the resulting confix
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// parser 'do the right thing'. This refactoring is done by the help of
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// the refactoring parsers (see the files refactoring.[hi]pp).
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//
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// Additionally special care must be taken, if the body parser is a
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// unary_parser_category type parser as
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//
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// confix_p(open, *anychar_p, close)
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//
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// which without any refactoring would result in
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//
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// start >> (*anychar_p - close) >> close
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//
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// and will not give the expected result (*anychar_p will eat up all the
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// input up to the end of the input stream). So we have to refactor this
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// into:
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//
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// start >> *(anychar_p - close) >> close
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//
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// what will give the correct result.
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//
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// The case, where the body parser is a combination of the two mentioned
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// problems (i.e. the body parser is a unary parser with an attached
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// action), is handled accordingly too:
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//
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// confix_p(start, (*anychar_p)[f], end)
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//
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// will be parsed as expected:
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//
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// start >> (*(anychar_p - end))[f] >> end.
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//
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///////////////////////////////////////////////////////////////////////////////
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template<typename NestedT, typename LexemeT>
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struct confix_parser_gen
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{
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// Generic generator function for creation of concrete confix parsers
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template<typename StartT, typename ExprT, typename EndT>
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struct paren_op_result_type
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{
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typedef confix_parser<
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typename as_parser<StartT>::type,
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typename as_parser<ExprT>::type,
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typename as_parser<EndT>::type,
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typename as_parser<ExprT>::type::parser_category_t,
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NestedT,
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LexemeT
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> type;
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};
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template<typename StartT, typename ExprT, typename EndT>
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typename paren_op_result_type<StartT, ExprT, EndT>::type
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operator()(StartT const &start_, ExprT const &expr_, EndT const &end_) const
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{
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typedef typename paren_op_result_type<StartT,ExprT,EndT>::type
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return_t;
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return return_t(
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as_parser<StartT>::convert(start_),
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as_parser<ExprT>::convert(expr_),
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as_parser<EndT>::convert(end_)
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);
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}
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// Generic generator function for creation of concrete confix parsers
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// which have an action directly attached to the ExprT part of the
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// parser (see comment above, no automatic refactoring)
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template<typename StartT, typename ExprT, typename EndT>
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struct direct_result_type
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{
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typedef confix_parser<
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typename as_parser<StartT>::type,
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typename as_parser<ExprT>::type,
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typename as_parser<EndT>::type,
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plain_parser_category, // do not re-attach action
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NestedT,
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LexemeT
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> type;
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};
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template<typename StartT, typename ExprT, typename EndT>
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typename direct_result_type<StartT,ExprT,EndT>::type
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direct(StartT const &start_, ExprT const &expr_, EndT const &end_) const
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{
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typedef typename direct_result_type<StartT,ExprT,EndT>::type
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return_t;
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return return_t(
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as_parser<StartT>::convert(start_),
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as_parser<ExprT>::convert(expr_),
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as_parser<EndT>::convert(end_)
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);
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}
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};
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///////////////////////////////////////////////////////////////////////////////
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//
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// Predefined non_nested confix parser generators
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//
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///////////////////////////////////////////////////////////////////////////////
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const confix_parser_gen<non_nested, non_lexeme> confix_p =
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confix_parser_gen<non_nested, non_lexeme>();
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///////////////////////////////////////////////////////////////////////////////
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//
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// Comments are special types of confix parsers
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//
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// Comment parser generator template. This is a helper for generating a
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// correct confix_parser<> from auxiliary parameters, which is able to
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// parse comment constructs: (StartToken >> Comment text >> EndToken).
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//
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// There are the following types supported as parameters yet: parsers,
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// single characters and strings (see as_parser).
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//
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// There are two diffenerent predefined comment parser generators
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// (comment_p and comment_nest_p, see below), which may be used for
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// creating special comment parsers in two different ways.
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//
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// If these are used with one parameter, a comment starting with the given
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// first parser parameter up to the end of the line is matched. So for
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// instance the following parser matches C++ style comments:
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//
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// comment_p("//").
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//
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// If these are used with two parameters, a comment starting with the
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// first parser parameter up to the second parser parameter is matched.
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// For instance a C style comment parser should be constrcuted as:
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//
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// comment_p("/*", "*/").
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//
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// Please note, that a comment is parsed implicitly as if the whole
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// comment_p(...) statement were embedded into a lexeme_d[] directive.
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//
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///////////////////////////////////////////////////////////////////////////////
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template<typename NestedT>
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struct comment_parser_gen
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{
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// Generic generator function for creation of concrete comment parsers
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// from an open token. The newline parser eol_p is used as the
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// closing token.
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template<typename StartT>
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struct paren_op1_result_type
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{
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typedef confix_parser<
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typename as_parser<StartT>::type,
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kleene_star<anychar_parser>,
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alternative<eol_parser, end_parser>,
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unary_parser_category, // there is no action to re-attach
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NestedT,
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is_lexeme // insert implicit lexeme_d[]
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>
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type;
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};
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template<typename StartT>
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typename paren_op1_result_type<StartT>::type
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operator() (StartT const &start_) const
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{
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typedef typename paren_op1_result_type<StartT>::type
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return_t;
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return return_t(
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as_parser<StartT>::convert(start_),
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*anychar_p,
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eol_p | end_p
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);
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}
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// Generic generator function for creation of concrete comment parsers
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// from an open and a close tokens.
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template<typename StartT, typename EndT>
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struct paren_op2_result_type
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{
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typedef confix_parser<
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typename as_parser<StartT>::type,
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kleene_star<anychar_parser>,
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typename as_parser<EndT>::type,
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unary_parser_category, // there is no action to re-attach
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NestedT,
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is_lexeme // insert implicit lexeme_d[]
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> type;
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};
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template<typename StartT, typename EndT>
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typename paren_op2_result_type<StartT,EndT>::type
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operator() (StartT const &start_, EndT const &end_) const
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{
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typedef typename paren_op2_result_type<StartT,EndT>::type
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return_t;
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return return_t(
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as_parser<StartT>::convert(start_),
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*anychar_p,
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as_parser<EndT>::convert(end_)
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);
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}
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};
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///////////////////////////////////////////////////////////////////////////////
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//
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// Predefined non_nested comment parser generator
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//
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///////////////////////////////////////////////////////////////////////////////
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const comment_parser_gen<non_nested> comment_p =
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comment_parser_gen<non_nested>();
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///////////////////////////////////////////////////////////////////////////////
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//
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// comment_nest_parser class
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//
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// Parses a nested comments.
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// Example: nested PASCAL-comments:
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//
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// { This is a { nested } PASCAL-comment }
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//
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///////////////////////////////////////////////////////////////////////////////
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template<typename OpenT, typename CloseT>
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struct comment_nest_parser:
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public parser<comment_nest_parser<OpenT, CloseT> >
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{
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typedef comment_nest_parser<OpenT, CloseT> self_t;
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comment_nest_parser(OpenT const &open_, CloseT const &close_):
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open(open_), close(close_)
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{}
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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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return do_parse(
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open >> *(*this | (anychar_p - close)) >> close,
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scan);
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}
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private:
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template<typename ParserT, typename ScannerT>
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typename parser_result<self_t, ScannerT>::type
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do_parse(ParserT const &p, ScannerT const &scan) const
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{
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return
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impl::contiguous_parser_parse<
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typename parser_result<ParserT, ScannerT>::type
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>(p, scan, scan);
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}
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typename as_parser<OpenT>::type::embed_t open;
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typename as_parser<CloseT>::type::embed_t close;
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};
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///////////////////////////////////////////////////////////////////////////////
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//
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// Predefined nested comment parser generator
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//
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///////////////////////////////////////////////////////////////////////////////
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template<typename OpenT, typename CloseT>
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struct comment_nest_p_result
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{
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typedef comment_nest_parser<
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typename as_parser<OpenT>::type,
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typename as_parser<CloseT>::type
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> type;
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};
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template<typename OpenT, typename CloseT>
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inline typename comment_nest_p_result<OpenT,CloseT>::type
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comment_nest_p(OpenT const &open, CloseT const &close)
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{
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typedef typename comment_nest_p_result<OpenT,CloseT>::type
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result_t;
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return result_t(
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as_parser<OpenT>::convert(open),
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as_parser<CloseT>::convert(close)
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);
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}
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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
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