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132 lines
4.0 KiB
132 lines
4.0 KiB
/*============================================================================= |
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Copyright (c) 2001-2011 Joel de Guzman |
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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_EPS_MARCH_23_2007_0454PM) |
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#define BOOST_SPIRIT_EPS_MARCH_23_2007_0454PM |
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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/domain.hpp> |
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#include <boost/spirit/home/qi/skip_over.hpp> |
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#include <boost/spirit/home/qi/meta_compiler.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/spirit/home/support/common_terminals.hpp> |
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#include <boost/fusion/include/at.hpp> |
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#include <boost/type_traits/is_convertible.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_terminal<qi::domain, tag::eps> // enables eps |
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: mpl::true_ {}; |
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template <typename A0> |
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struct use_terminal<qi::domain |
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, terminal_ex<tag::eps, fusion::vector1<A0> > // enables eps(bool-condition) |
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> : is_convertible<A0, bool> {}; |
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template <> // enables eps(f) |
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struct use_lazy_terminal< |
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qi::domain, tag::eps, 1 /*arity*/ |
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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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#ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS |
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using spirit::eps; |
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#endif |
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using spirit::eps_type; |
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struct eps_parser : primitive_parser<eps_parser> |
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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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typedef unused_type type; |
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}; |
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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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qi::skip_over(first, last, skipper); |
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return true; |
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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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return info("eps"); |
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} |
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}; |
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struct semantic_predicate : primitive_parser<semantic_predicate> |
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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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typedef unused_type type; |
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}; |
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semantic_predicate(bool predicate) |
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: predicate(predicate) {} |
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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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qi::skip_over(first, last, skipper); |
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return predicate; |
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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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return info("semantic-predicate"); |
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} |
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bool predicate; |
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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 Modifiers> |
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struct make_primitive<tag::eps, Modifiers> |
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{ |
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typedef eps_parser result_type; |
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result_type operator()(unused_type, unused_type) const |
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{ |
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return result_type(); |
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} |
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}; |
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template <typename Modifiers, typename A0> |
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struct make_primitive< |
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terminal_ex<tag::eps, fusion::vector1<A0> > |
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, Modifiers> |
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{ |
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typedef semantic_predicate result_type; |
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template <typename Terminal> |
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result_type operator()(Terminal const& term, unused_type) const |
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{ |
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return result_type(fusion::at_c<0>(term.args) ? true : false); |
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} |
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}; |
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}}} |
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#endif
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