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291 lines
8.1 KiB
291 lines
8.1 KiB
/*============================================================================== |
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Copyright (c) 2001-2010 Joel de Guzman |
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Copyright (c) 2010 Thomas Heller |
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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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#ifndef BOOST_PHOENIX_STATEMENT_SWITCH_HPP |
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#define BOOST_PHOENIX_STATEMENT_SWITCH_HPP |
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#include <boost/phoenix/core/limits.hpp> |
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#include <boost/fusion/iterator/advance.hpp> |
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#include <boost/phoenix/core/call.hpp> |
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#include <boost/phoenix/core/expression.hpp> |
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#include <boost/phoenix/core/meta_grammar.hpp> |
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#include <boost/phoenix/core/is_nullary.hpp> |
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#include <boost/phoenix/support/iterate.hpp> |
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#include <boost/proto/make_expr.hpp> |
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#include <boost/proto/fusion.hpp> |
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BOOST_PHOENIX_DEFINE_EXPRESSION( |
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(boost)(phoenix)(switch_case) |
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, (proto::terminal<proto::_>) |
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(meta_grammar) |
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) |
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BOOST_PHOENIX_DEFINE_EXPRESSION( |
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(boost)(phoenix)(switch_default_case) |
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, (meta_grammar) |
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) |
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namespace boost { namespace phoenix |
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{ |
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namespace detail |
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{ |
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struct switch_case_grammar; |
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struct switch_case_with_default_grammar; |
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struct switch_grammar |
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: proto::or_< |
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proto::when< |
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detail::switch_case_grammar |
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, mpl::false_() |
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> |
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, proto::when< |
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detail::switch_case_with_default_grammar |
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, mpl::true_() |
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> |
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> |
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{}; |
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} |
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namespace detail |
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{ |
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struct switch_case_is_nullary |
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: proto::or_< |
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proto::when< |
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proto::comma< |
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switch_case_is_nullary |
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, proto::or_<phoenix::rule::switch_default_case, phoenix::rule::switch_case> |
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> |
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, mpl::and_< |
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switch_case_is_nullary( |
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proto::_child_c<0> |
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, proto::_state |
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) |
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, switch_case_is_nullary( |
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proto::_child_c<1> |
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, proto::_state |
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) |
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>() |
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> |
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, proto::when< |
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proto::or_<phoenix::rule::switch_default_case, phoenix::rule::switch_case> |
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, evaluator(proto::_child_c<0>, proto::_state) |
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> |
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> |
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{}; |
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struct switch_case_grammar |
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: proto::or_< |
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proto::comma<switch_case_grammar, phoenix::rule::switch_case> |
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, proto::when<phoenix::rule::switch_case, proto::_> |
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> |
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{}; |
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struct switch_case_with_default_grammar |
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: proto::or_< |
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proto::comma<switch_case_grammar, phoenix::rule::switch_default_case> |
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, proto::when<phoenix::rule::switch_default_case, proto::_> |
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> |
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{}; |
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struct switch_size |
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: proto::or_< |
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proto::when< |
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proto::comma<switch_size, proto::_> |
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, mpl::next<switch_size(proto::_left)>() |
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> |
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, proto::when<proto::_, mpl::int_<1>()> |
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> |
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{}; |
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} |
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}} |
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BOOST_PHOENIX_DEFINE_EXPRESSION( |
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(boost)(phoenix)(switch_) |
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, (meta_grammar) // Cond |
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(detail::switch_grammar) // Cases |
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) |
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namespace boost { namespace phoenix { |
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template <typename Dummy> |
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struct is_nullary::when<rule::switch_, Dummy> |
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: proto::and_< |
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evaluator(proto::_child_c<0>, _context) |
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, detail::switch_case_is_nullary(proto::_child_c<1>, _context) |
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> |
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{}; |
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struct switch_eval |
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{ |
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typedef void result_type; |
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template <typename Context> |
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result_type |
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operator()(Context &) const |
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{ |
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} |
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template <typename Cond, typename Cases, typename Context> |
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result_type |
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operator()(Cond const & cond, Cases const & cases, Context & ctx) const |
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{ |
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this->evaluate( |
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ctx |
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, cond |
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, cases |
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, typename detail::switch_size::impl<Cases, int, int>::result_type() |
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, typename detail::switch_grammar::impl<Cases, int, int>::result_type() |
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); |
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} |
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private: |
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template <typename Context, typename Cond, typename Cases> |
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result_type |
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evaluate( |
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Context & ctx |
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, Cond const & cond |
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, Cases const & cases |
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, mpl::int_<1> |
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, mpl::false_ |
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) const |
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{ |
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typedef |
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typename proto::result_of::value< |
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typename proto::result_of::child_c< |
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Cases |
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, 0 |
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>::type |
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>::type |
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case_label; |
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switch(boost::phoenix::eval(cond, ctx)) |
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{ |
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case case_label::value: |
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boost::phoenix::eval(proto::child_c<1>(cases), ctx); |
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} |
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} |
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template <typename Context, typename Cond, typename Cases> |
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result_type |
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evaluate( |
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Context & ctx |
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, Cond const & cond |
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, Cases const & cases |
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, mpl::int_<1> |
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, mpl::true_ |
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) const |
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{ |
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switch(boost::phoenix::eval(cond, ctx)) |
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{ |
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default: |
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boost::phoenix::eval(proto::child_c<0>(cases), ctx); |
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} |
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} |
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// Bring in the evaluation functions |
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#include <boost/phoenix/statement/detail/switch.hpp> |
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}; |
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template <typename Dummy> |
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struct default_actions::when<rule::switch_, Dummy> |
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: call<switch_eval> |
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{}; |
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template <int N, typename A> |
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inline |
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typename proto::result_of::make_expr< |
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tag::switch_case |
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, proto::basic_default_domain |
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, mpl::int_<N> |
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, A |
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>::type const |
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case_(A const & a) |
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{ |
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return |
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proto::make_expr< |
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tag::switch_case |
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, proto::basic_default_domain |
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>( |
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mpl::int_<N>() |
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, a |
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); |
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} |
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template <typename A> |
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inline |
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typename proto::result_of::make_expr< |
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tag::switch_default_case |
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, proto::basic_default_domain |
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, A |
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>::type const |
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default_(A const& a) |
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{ |
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return |
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proto::make_expr< |
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tag::switch_default_case |
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, proto::basic_default_domain |
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>(a); |
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} |
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template <typename Cond> |
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struct switch_gen |
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{ |
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switch_gen(Cond const& cond) : cond(cond) {} |
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template <typename Cases> |
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typename expression::switch_< |
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Cond |
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, Cases |
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>::type |
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operator[](Cases const& cases) const |
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{ |
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return |
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this->generate( |
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cases |
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, proto::matches<Cases, detail::switch_grammar>() |
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); |
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} |
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private: |
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Cond const& cond; |
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template <typename Cases> |
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typename expression::switch_< |
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Cond |
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, Cases |
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>::type |
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generate(Cases const & cases, mpl::true_) const |
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{ |
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return expression::switch_<Cond, Cases>::make(cond, cases); |
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} |
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template <typename Cases> |
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typename expression::switch_< |
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Cond |
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, Cases |
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>::type |
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generate(Cases const &, mpl::false_) const |
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{ |
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BOOST_MPL_ASSERT_MSG( |
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false |
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, INVALID_SWITCH_CASE_STATEMENT |
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, (Cases) |
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); |
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} |
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}; |
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template <typename Cond> |
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inline |
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switch_gen<Cond> const |
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switch_(Cond const& cond) |
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{ |
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return switch_gen<Cond>(cond); |
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} |
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}} |
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#endif |
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