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- /*=============================================================================
- Copyright (c) 1998-2003 Joel de Guzman
- Copyright (c) 2001 Daniel Nuffer
- Copyright (c) 2002 Hartmut Kaiser
- http://spirit.sourceforge.net/
- Distributed under the Boost Software License, Version 1.0. (See accompanying
- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- =============================================================================*/
- #if !defined(BOOST_SPIRIT_SEQUENTIAL_OR_HPP)
- #define BOOST_SPIRIT_SEQUENTIAL_OR_HPP
- #include <boost/spirit/home/classic/namespace.hpp>
- #include <boost/spirit/home/classic/core/parser.hpp>
- #include <boost/spirit/home/classic/core/primitives/primitives.hpp>
- #include <boost/spirit/home/classic/core/composite/composite.hpp>
- #include <boost/spirit/home/classic/meta/as_parser.hpp>
- namespace boost { namespace spirit {
- BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
- ///////////////////////////////////////////////////////////////////////////
- //
- // sequential-or class
- //
- // Handles expressions of the form:
- //
- // a || b
- //
- // Equivalent to
- //
- // a | b | a >> b;
- //
- // where a and b are parsers. The expression returns a composite
- // parser that matches matches a or b in sequence. One (not both) of
- // the operands may be a literal char, wchar_t or a primitive string
- // char const*, wchar_t const*.
- //
- ///////////////////////////////////////////////////////////////////////////
- struct sequential_or_parser_gen;
-
- template <typename A, typename B>
- struct sequential_or : public binary<A, B, parser<sequential_or<A, B> > >
- {
- typedef sequential_or<A, B> self_t;
- typedef binary_parser_category parser_category_t;
- typedef sequential_or_parser_gen parser_generator_t;
- typedef binary<A, B, parser<self_t> > base_t;
-
- sequential_or(A const& a, B const& b)
- : base_t(a, b) {}
-
- template <typename ScannerT>
- typename parser_result<self_t, ScannerT>::type
- parse(ScannerT const& scan) const
- {
- typedef typename parser_result<self_t, ScannerT>::type result_t;
- typedef typename ScannerT::iterator_t iterator_t;
- { // scope for save
- iterator_t save = scan.first;
- if (result_t ma = this->left().parse(scan))
- {
- save = scan.first;
- if (result_t mb = this->right().parse(scan))
- {
- // matched a b
- scan.concat_match(ma, mb);
- return ma;
- }
- else
- {
- // matched a
- scan.first = save;
- return ma;
- }
- }
- scan.first = save;
- }
-
- // matched b
- return this->right().parse(scan);
- }
- };
-
- struct sequential_or_parser_gen
- {
- template <typename A, typename B>
- struct result
- {
- typedef
- sequential_or<
- typename as_parser<A>::type
- , typename as_parser<B>::type
- >
- type;
- };
-
- template <typename A, typename B>
- static sequential_or<
- typename as_parser<A>::type
- , typename as_parser<B>::type
- >
- generate(A const& a, B const& b)
- {
- return sequential_or<BOOST_DEDUCED_TYPENAME as_parser<A>::type,
- BOOST_DEDUCED_TYPENAME as_parser<B>::type>
- (as_parser<A>::convert(a), as_parser<B>::convert(b));
- }
- };
-
- template <typename A, typename B>
- sequential_or<A, B>
- operator||(parser<A> const& a, parser<B> const& b);
-
- template <typename A>
- sequential_or<A, chlit<char> >
- operator||(parser<A> const& a, char b);
-
- template <typename B>
- sequential_or<chlit<char>, B>
- operator||(char a, parser<B> const& b);
-
- template <typename A>
- sequential_or<A, strlit<char const*> >
- operator||(parser<A> const& a, char const* b);
-
- template <typename B>
- sequential_or<strlit<char const*>, B>
- operator||(char const* a, parser<B> const& b);
- template <typename A>
- sequential_or<A, chlit<wchar_t> >
- operator||(parser<A> const& a, wchar_t b);
-
- template <typename B>
- sequential_or<chlit<wchar_t>, B>
- operator||(wchar_t a, parser<B> const& b);
-
- template <typename A>
- sequential_or<A, strlit<wchar_t const*> >
- operator||(parser<A> const& a, wchar_t const* b);
-
- template <typename B>
- sequential_or<strlit<wchar_t const*>, B>
- operator||(wchar_t const* a, parser<B> const& b);
- BOOST_SPIRIT_CLASSIC_NAMESPACE_END
- }} // namespace BOOST_SPIRIT_CLASSIC_NS
- #endif
- #include <boost/spirit/home/classic/core/composite/impl/sequential_or.ipp>
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