92 lines
3.4 KiB
C++
92 lines
3.4 KiB
C++
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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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//
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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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#if !defined(BOOST_SPIRIT_KARMA_REFERENCE_APR_17_2009_1057PM)
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#define BOOST_SPIRIT_KARMA_REFERENCE_APR_17_2009_1057PM
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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/karma/meta_compiler.hpp>
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#include <boost/spirit/home/karma/generator.hpp>
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#include <boost/spirit/home/support/info.hpp>
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#include <boost/spirit/home/support/handles_container.hpp>
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#include <boost/type_traits/remove_const.hpp>
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#include <boost/ref.hpp>
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namespace boost { namespace spirit { namespace karma
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{
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///////////////////////////////////////////////////////////////////////////
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// reference is a generator that references another generator (its Subject)
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///////////////////////////////////////////////////////////////////////////
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template <typename Subject>
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struct reference : generator<reference<Subject> >
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{
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typedef mpl::int_<generator_properties::all_properties> properties;
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typedef Subject subject_type;
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reference(Subject& subject)
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: ref(subject) {}
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template <typename Context, typename Unused>
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struct attribute : Subject::template attribute<Context, Unused> {};
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// Default overload, used whenever the attribute is not unused and not
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// used from an aliased rule.
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template <typename OutputIterator, typename Context
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, typename Delimiter, typename Attribute>
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bool generate(OutputIterator& sink, Context& context
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, Delimiter const& delim, Attribute const& attr) const
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{
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return ref.get().generate(sink, context, delim, attr);
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}
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// This overload gets called from an aliased rule only, we take the
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// attribute from the context provided from the wrapper rule.
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template <typename OutputIterator, typename Context
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, typename Delimiter>
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bool generate(OutputIterator& sink, Context& context
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, Delimiter const& delim, unused_type) const
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{
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return ref.get().generate(sink, context, delim, context.attributes);
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}
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// This overload is used whenever no attribute is given and it is used
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// not from an aliased rule.
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template <typename OutputIterator, typename Delimiter>
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bool generate(OutputIterator& sink, unused_type
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, Delimiter const& delim, unused_type) const
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{
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return ref.get().generate(sink, unused, delim, unused);
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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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// the reference is transparent (does not add any info)
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return ref.get().what(context);
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}
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boost::reference_wrapper<Subject> ref;
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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 Subject, typename Attribute, typename Context
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, typename Iterator>
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struct handles_container<karma::reference<Subject>, Attribute
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, Context, Iterator>
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: handles_container<typename remove_const<Subject>::type, Attribute
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, Context, Iterator>
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{};
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}}}
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#endif
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