155 lines
5.1 KiB
Plaintext
155 lines
5.1 KiB
Plaintext
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/*=============================================================================
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Copyright (c) 1998-2003 Joel de Guzman
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Copyright (c) 2001 Daniel Nuffer
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Copyright (c) 2002 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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#if !defined(BOOST_SPIRIT_SEQUENTIAL_OR_HPP)
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#define BOOST_SPIRIT_SEQUENTIAL_OR_HPP
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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/primitives/primitives.hpp>
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#include <boost/spirit/home/classic/core/composite/composite.hpp>
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#include <boost/spirit/home/classic/meta/as_parser.hpp>
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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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// sequential-or class
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//
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// Handles expressions of the form:
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//
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// a || b
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//
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// Equivalent to
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//
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// a | b | a >> b;
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//
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// where a and b are parsers. The expression returns a composite
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// parser that matches matches a or b in sequence. One (not both) of
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// the operands may be a literal char, wchar_t or a primitive string
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// char const*, wchar_t const*.
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//
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///////////////////////////////////////////////////////////////////////////
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struct sequential_or_parser_gen;
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template <typename A, typename B>
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struct sequential_or : public binary<A, B, parser<sequential_or<A, B> > >
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{
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typedef sequential_or<A, B> self_t;
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typedef binary_parser_category parser_category_t;
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typedef sequential_or_parser_gen parser_generator_t;
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typedef binary<A, B, parser<self_t> > base_t;
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sequential_or(A const& a, B const& b)
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: base_t(a, b) {}
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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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typedef typename ScannerT::iterator_t iterator_t;
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{ // scope for save
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iterator_t save = scan.first;
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if (result_t ma = this->left().parse(scan))
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{
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save = scan.first;
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if (result_t mb = this->right().parse(scan))
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{
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// matched a b
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scan.concat_match(ma, mb);
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return ma;
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}
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else
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{
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// matched a
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scan.first = save;
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return ma;
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}
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}
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scan.first = save;
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}
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// matched b
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return this->right().parse(scan);
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}
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};
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struct sequential_or_parser_gen
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{
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template <typename A, typename B>
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struct result
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{
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typedef
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sequential_or<
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typename as_parser<A>::type
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, typename as_parser<B>::type
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>
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type;
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};
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template <typename A, typename B>
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static sequential_or<
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typename as_parser<A>::type
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, typename as_parser<B>::type
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>
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generate(A const& a, B const& b)
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{
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return sequential_or<BOOST_DEDUCED_TYPENAME as_parser<A>::type,
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BOOST_DEDUCED_TYPENAME as_parser<B>::type>
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(as_parser<A>::convert(a), as_parser<B>::convert(b));
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}
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};
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template <typename A, typename B>
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sequential_or<A, B>
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operator||(parser<A> const& a, parser<B> const& b);
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template <typename A>
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sequential_or<A, chlit<char> >
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operator||(parser<A> const& a, char b);
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template <typename B>
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sequential_or<chlit<char>, B>
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operator||(char a, parser<B> const& b);
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template <typename A>
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sequential_or<A, strlit<char const*> >
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operator||(parser<A> const& a, char const* b);
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template <typename B>
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sequential_or<strlit<char const*>, B>
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operator||(char const* a, parser<B> const& b);
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template <typename A>
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sequential_or<A, chlit<wchar_t> >
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operator||(parser<A> const& a, wchar_t b);
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template <typename B>
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sequential_or<chlit<wchar_t>, B>
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operator||(wchar_t a, parser<B> const& b);
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template <typename A>
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sequential_or<A, strlit<wchar_t const*> >
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operator||(parser<A> const& a, wchar_t const* b);
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template <typename B>
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sequential_or<strlit<wchar_t const*>, B>
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operator||(wchar_t const* a, parser<B> const& b);
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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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#include <boost/spirit/home/classic/core/composite/impl/sequential_or.ipp>
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