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118 lines
4.4 KiB
118 lines
4.4 KiB
/*============================================================================= |
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Copyright (c) 2001-2011 Joel de Guzman |
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Copyright (c) 2001-2011 Hartmut Kaiser |
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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(SPIRIT_ALTERNATIVE_FEBRUARY_05_2007_1153AM) |
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#define SPIRIT_ALTERNATIVE_FEBRUARY_05_2007_1153AM |
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#if defined(_MSC_VER) |
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#pragma once |
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#endif |
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#include <boost/spirit/home/qi/detail/alternative_function.hpp> |
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#include <boost/spirit/home/qi/meta_compiler.hpp> |
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#include <boost/spirit/home/qi/parser.hpp> |
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#include <boost/spirit/home/qi/detail/attributes.hpp> |
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#include <boost/spirit/home/support/has_semantic_action.hpp> |
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#include <boost/spirit/home/support/handles_container.hpp> |
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#include <boost/spirit/home/support/detail/what_function.hpp> |
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#include <boost/spirit/home/support/unused.hpp> |
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#include <boost/spirit/home/support/info.hpp> |
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#include <boost/fusion/include/any.hpp> |
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#include <boost/fusion/include/mpl.hpp> |
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#include <boost/fusion/include/for_each.hpp> |
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namespace boost { namespace spirit |
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{ |
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/////////////////////////////////////////////////////////////////////////// |
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// Enablers |
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/////////////////////////////////////////////////////////////////////////// |
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template <> |
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struct use_operator<qi::domain, proto::tag::bitwise_or> // enables | |
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: mpl::true_ {}; |
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template <> |
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struct flatten_tree<qi::domain, proto::tag::bitwise_or> // flattens | |
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: mpl::true_ {}; |
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}} |
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namespace boost { namespace spirit { namespace qi |
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{ |
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template <typename Elements> |
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struct alternative : nary_parser<alternative<Elements> > |
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{ |
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template <typename Context, typename Iterator> |
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struct attribute |
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{ |
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// Put all the element attributes in a tuple |
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typedef typename traits::build_attribute_sequence< |
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Elements, Context, traits::alternative_attribute_transform |
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, Iterator, qi::domain |
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>::type all_attributes; |
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// Ok, now make a variant over the attribute sequence. Note that |
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// build_variant makes sure that 1) all attributes in the variant |
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// are unique 2) puts the unused attribute, if there is any, to |
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// the front and 3) collapses single element variants, variant<T> |
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// to T. |
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typedef typename |
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traits::build_variant<all_attributes>::type |
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type; |
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}; |
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alternative(Elements const& elements) |
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: elements(elements) {} |
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template <typename Iterator, typename Context |
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, typename Skipper, typename Attribute> |
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bool parse(Iterator& first, Iterator const& last |
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, Context& context, Skipper const& skipper |
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, Attribute& attr) const |
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{ |
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detail::alternative_function<Iterator, Context, Skipper, Attribute> |
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f(first, last, context, skipper, attr); |
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// return true if *any* of the parsers succeed |
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return fusion::any(elements, f); |
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} |
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template <typename Context> |
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info what(Context& context) const |
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{ |
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info result("alternative"); |
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fusion::for_each(elements, |
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spirit::detail::what_function<Context>(result, context)); |
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return result; |
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} |
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Elements elements; |
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}; |
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/////////////////////////////////////////////////////////////////////////// |
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// Parser generators: make_xxx function (objects) |
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/////////////////////////////////////////////////////////////////////////// |
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template <typename Elements, typename Modifiers> |
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struct make_composite<proto::tag::bitwise_or, Elements, Modifiers> |
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: make_nary_composite<Elements, alternative> |
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{}; |
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}}} |
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namespace boost { namespace spirit { namespace traits |
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{ |
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/////////////////////////////////////////////////////////////////////////// |
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template <typename Elements> |
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struct has_semantic_action<qi::alternative<Elements> > |
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: nary_has_semantic_action<Elements> {}; |
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/////////////////////////////////////////////////////////////////////////// |
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template <typename Elements, typename Attribute, typename Context |
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, typename Iterator> |
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struct handles_container<qi::alternative<Elements>, Attribute, Context |
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, Iterator> |
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: nary_handles_container<Elements, Attribute, Context, Iterator> {}; |
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}}} |
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#endif
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