| /*============================================================================== |
| Copyright (c) 2001-2010 Joel de Guzman |
| Copyright (c) 2010 Thomas Heller |
| |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| ==============================================================================*/ |
| #ifndef BOOST_PHOENIX_STATEMENT_SWITCH_HPP |
| #define BOOST_PHOENIX_STATEMENT_SWITCH_HPP |
| |
| #include <boost/phoenix/core/limits.hpp> |
| #include <boost/fusion/iterator/advance.hpp> |
| #include <boost/phoenix/core/call.hpp> |
| #include <boost/phoenix/core/expression.hpp> |
| #include <boost/phoenix/core/meta_grammar.hpp> |
| #include <boost/phoenix/core/is_nullary.hpp> |
| #include <boost/phoenix/support/iterate.hpp> |
| #include <boost/proto/make_expr.hpp> |
| #include <boost/proto/fusion.hpp> |
| |
| BOOST_PHOENIX_DEFINE_EXPRESSION( |
| (boost)(phoenix)(switch_case) |
| , (proto::terminal<proto::_>) |
| (meta_grammar) |
| ) |
| |
| BOOST_PHOENIX_DEFINE_EXPRESSION( |
| (boost)(phoenix)(switch_default_case) |
| , (meta_grammar) |
| ) |
| |
| namespace boost { namespace phoenix |
| { |
| namespace detail |
| { |
| struct switch_case_grammar; |
| struct switch_case_with_default_grammar; |
| struct switch_grammar |
| : proto::or_< |
| proto::when< |
| detail::switch_case_grammar |
| , mpl::false_() |
| > |
| , proto::when< |
| detail::switch_case_with_default_grammar |
| , mpl::true_() |
| > |
| > |
| {}; |
| } |
| |
| namespace detail |
| { |
| struct switch_case_is_nullary |
| : proto::or_< |
| proto::when< |
| proto::comma< |
| switch_case_is_nullary |
| , proto::or_<phoenix::rule::switch_default_case, phoenix::rule::switch_case> |
| > |
| , mpl::and_< |
| switch_case_is_nullary( |
| proto::_child_c<0> |
| , proto::_state |
| ) |
| , switch_case_is_nullary( |
| proto::_child_c<1> |
| , proto::_state |
| ) |
| >() |
| > |
| , proto::when< |
| proto::or_<phoenix::rule::switch_default_case, phoenix::rule::switch_case> |
| , evaluator(proto::_child_c<0>, proto::_state) |
| > |
| > |
| {}; |
| |
| struct switch_case_grammar |
| : proto::or_< |
| proto::comma<switch_case_grammar, phoenix::rule::switch_case> |
| , proto::when<phoenix::rule::switch_case, proto::_> |
| > |
| {}; |
| |
| struct switch_case_with_default_grammar |
| : proto::or_< |
| proto::comma<switch_case_grammar, phoenix::rule::switch_default_case> |
| , proto::when<phoenix::rule::switch_default_case, proto::_> |
| > |
| {}; |
| |
| struct switch_size |
| : proto::or_< |
| proto::when< |
| proto::comma<switch_size, proto::_> |
| , mpl::next<switch_size(proto::_left)>() |
| > |
| , proto::when<proto::_, mpl::int_<1>()> |
| > |
| {}; |
| } |
| }} |
| |
| BOOST_PHOENIX_DEFINE_EXPRESSION( |
| (boost)(phoenix)(switch_) |
| , (meta_grammar) // Cond |
| (detail::switch_grammar) // Cases |
| ) |
| |
| namespace boost { namespace phoenix { |
| |
| template <typename Dummy> |
| struct is_nullary::when<rule::switch_, Dummy> |
| : proto::and_< |
| evaluator(proto::_child_c<0>, _context) |
| , detail::switch_case_is_nullary(proto::_child_c<1>, _context) |
| > |
| {}; |
| |
| struct switch_eval |
| { |
| typedef void result_type; |
| |
| template <typename Context> |
| result_type |
| operator()(Context &) const |
| { |
| } |
| |
| template <typename Cond, typename Cases, typename Context> |
| result_type |
| operator()(Cond const & cond, Cases const & cases, Context & ctx) const |
| { |
| this->evaluate( |
| ctx |
| , cond |
| , cases |
| , typename detail::switch_size::impl<Cases, int, int>::result_type() |
| , typename detail::switch_grammar::impl<Cases, int, int>::result_type() |
| ); |
| } |
| |
| private: |
| template <typename Context, typename Cond, typename Cases> |
| result_type |
| evaluate( |
| Context & ctx |
| , Cond const & cond |
| , Cases const & cases |
| , mpl::int_<1> |
| , mpl::false_ |
| ) const |
| { |
| typedef |
| typename proto::result_of::value< |
| typename proto::result_of::child_c< |
| Cases |
| , 0 |
| >::type |
| >::type |
| case_label; |
| |
| switch(boost::phoenix::eval(cond, ctx)) |
| { |
| case case_label::value: |
| boost::phoenix::eval(proto::child_c<1>(cases), ctx); |
| } |
| } |
| |
| template <typename Context, typename Cond, typename Cases> |
| result_type |
| evaluate( |
| Context & ctx |
| , Cond const & cond |
| , Cases const & cases |
| , mpl::int_<1> |
| , mpl::true_ |
| ) const |
| { |
| switch(boost::phoenix::eval(cond, ctx)) |
| { |
| default: |
| boost::phoenix::eval(proto::child_c<0>(cases), ctx); |
| } |
| } |
| |
| // Bring in the evaluation functions |
| #include <boost/phoenix/statement/detail/switch.hpp> |
| }; |
| |
| template <typename Dummy> |
| struct default_actions::when<rule::switch_, Dummy> |
| : call<switch_eval> |
| {}; |
| |
| template <int N, typename A> |
| inline |
| typename proto::result_of::make_expr< |
| tag::switch_case |
| , proto::basic_default_domain |
| , mpl::int_<N> |
| , A |
| >::type const |
| case_(A const & a) |
| { |
| return |
| proto::make_expr< |
| tag::switch_case |
| , proto::basic_default_domain |
| >( |
| mpl::int_<N>() |
| , a |
| ); |
| } |
| |
| template <typename A> |
| inline |
| typename proto::result_of::make_expr< |
| tag::switch_default_case |
| , proto::basic_default_domain |
| , A |
| >::type const |
| default_(A const& a) |
| { |
| return |
| proto::make_expr< |
| tag::switch_default_case |
| , proto::basic_default_domain |
| >(a); |
| } |
| |
| template <typename Cond> |
| struct switch_gen |
| { |
| switch_gen(Cond const& cond) : cond(cond) {} |
| |
| template <typename Cases> |
| typename expression::switch_< |
| Cond |
| , Cases |
| >::type |
| operator[](Cases const& cases) const |
| { |
| return |
| this->generate( |
| cases |
| , proto::matches<Cases, detail::switch_grammar>() |
| ); |
| } |
| |
| private: |
| Cond const& cond; |
| |
| template <typename Cases> |
| typename expression::switch_< |
| Cond |
| , Cases |
| >::type |
| generate(Cases const & cases, mpl::true_) const |
| { |
| return expression::switch_<Cond, Cases>::make(cond, cases); |
| } |
| |
| template <typename Cases> |
| typename expression::switch_< |
| Cond |
| , Cases |
| >::type |
| generate(Cases const &, mpl::false_) const |
| { |
| BOOST_MPL_ASSERT_MSG( |
| false |
| , INVALID_SWITCH_CASE_STATEMENT |
| , (Cases) |
| ); |
| } |
| }; |
| |
| template <typename Cond> |
| inline |
| switch_gen<Cond> const |
| switch_(Cond const& cond) |
| { |
| return switch_gen<Cond>(cond); |
| } |
| |
| }} |
| |
| #endif |
| |
