epoc32/include/stdapis/boost/variant/detail/apply_visitor_binary.hpp
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:27:01 +0100
branchSymbian2
changeset 3 e1b950c65cb4
permissions -rw-r--r--
Attempt to represent the S^2->S^3 header reorganisation as a series of "hg rename" operations
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//-----------------------------------------------------------------------------
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// boost variant/detail/apply_visitor_binary.hpp header file
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// See http://www.boost.org for updates, documentation, and revision history.
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//-----------------------------------------------------------------------------
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//
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// Copyright (c) 2002-2003
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// Eric Friedman
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP
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#define BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP
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#include "boost/config.hpp"
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#include "boost/detail/workaround.hpp"
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#include "boost/variant/detail/generic_result_type.hpp"
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#include "boost/variant/detail/apply_visitor_unary.hpp"
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#include "boost/utility/enable_if.hpp"
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namespace boost {
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//////////////////////////////////////////////////////////////////////////
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// function template apply_visitor(visitor, visitable1, visitable2)
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//
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// Visits visitable1 and visitable2 such that their values (which we
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// shall call x and y, respectively) are used as arguments in the
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// expression visitor(x, y).
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//
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namespace detail { namespace variant {
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template <typename Visitor, typename Value1>
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class apply_visitor_binary_invoke
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{
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public: // visitor typedefs
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    typedef typename Visitor::result_type
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        result_type;
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private: // representation
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    Visitor& visitor_;
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    Value1& value1_;
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public: // structors
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    apply_visitor_binary_invoke(Visitor& visitor, Value1& value1)
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        : visitor_(visitor)
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        , value1_(value1)
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    {
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    }
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public: // visitor interfaces
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    template <typename Value2>
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        BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
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    operator()(Value2& value2)
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    {
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        return visitor_(value1_, value2);
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    }
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};
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template <typename Visitor, typename Visitable2>
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class apply_visitor_binary_unwrap
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{
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public: // visitor typedefs
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    typedef typename Visitor::result_type
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        result_type;
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private: // representation
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    Visitor& visitor_;
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    Visitable2& visitable2_;
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public: // structors
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    apply_visitor_binary_unwrap(Visitor& visitor, Visitable2& visitable2)
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        : visitor_(visitor)
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        , visitable2_(visitable2)
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    {
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    }
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public: // visitor interfaces
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    template <typename Value1>
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        BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(result_type)
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    operator()(Value1& value1)
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    {
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        apply_visitor_binary_invoke<
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              Visitor
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            , Value1
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            > invoker(visitor_, value1);
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        return boost::apply_visitor(invoker, visitable2_);
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    }
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};
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}} // namespace detail::variant
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//
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// nonconst-visitor version:
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//
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#if !BOOST_WORKAROUND(__EDG__, BOOST_TESTED_AT(302))
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#   define BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(V) \
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    BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(typename V::result_type) \
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    /**/
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#else // EDG-based compilers
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#   define BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(V) \
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    typename enable_if< \
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          mpl::not_< is_const< V > > \
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        , BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(typename V::result_type) \
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        >::type \
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    /**/
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#endif // EDG-based compilers workaround
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template <typename Visitor, typename Visitable1, typename Visitable2>
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inline
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    BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE(Visitor)
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apply_visitor(
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      Visitor& visitor
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    , Visitable1& visitable1, Visitable2& visitable2
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    )
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{
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    ::boost::detail::variant::apply_visitor_binary_unwrap<
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          Visitor, Visitable2
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        > unwrapper(visitor, visitable2);
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    return boost::apply_visitor(unwrapper, visitable1);
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}
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#undef BOOST_VARIANT_AUX_APPLY_VISITOR_NON_CONST_RESULT_TYPE
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//
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// const-visitor version:
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//
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#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
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template <typename Visitor, typename Visitable1, typename Visitable2>
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inline
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    BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(
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          typename Visitor::result_type
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        )
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apply_visitor(
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      const Visitor& visitor
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    , Visitable1& visitable1, Visitable2& visitable2
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    )
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{
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    ::boost::detail::variant::apply_visitor_binary_unwrap<
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          const Visitor, Visitable2
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        > unwrapper(visitor, visitable2);
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    return boost::apply_visitor(unwrapper, visitable1);
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}
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#endif // MSVC7 and below exclusion
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} // namespace boost
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#endif // BOOST_VARIANT_DETAIL_APPLY_VISITOR_BINARY_HPP