161 lines
5.4 KiB
Plaintext
161 lines
5.4 KiB
Plaintext
/*=============================================================================
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Copyright (c) 2001-2007 Joel de Guzman
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Copyright (c) 2015 Kohei Takahashi
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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_CORE_DETAIL_FUNCTION_EVAL_HPP
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#define BOOST_PHOENIX_CORE_DETAIL_FUNCTION_EVAL_HPP
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#include <boost/phoenix/core/limits.hpp>
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#include <boost/phoenix/support/iterate.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/detail/phx2_result.hpp>
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#include <boost/utility/result_of.hpp>
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#ifndef BOOST_PHOENIX_NO_VARIADIC_FUNCTION_EVAL
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# include <boost/mpl/if.hpp>
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# include <boost/type_traits/is_reference.hpp>
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#endif
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#ifdef BOOST_PHOENIX_NO_VARIADIC_EXPRESSION
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# include <boost/phoenix/core/detail/cpp03/function_eval_expr.hpp>
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#else
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BOOST_PHOENIX_DEFINE_EXPRESSION_VARARG(
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(boost)(phoenix)(detail)(function_eval)
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, (meta_grammar)(meta_grammar)
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, _
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)
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#endif
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namespace boost { namespace phoenix {
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namespace detail
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{
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template <typename T>
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T& help_rvalue_deduction(T& x)
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{
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return x;
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}
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template <typename T>
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T const& help_rvalue_deduction(T const& x)
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{
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return x;
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}
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struct function_eval
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{
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template <typename Sig>
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struct result;
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#ifdef BOOST_PHOENIX_NO_VARIADIC_FUNCTION_EVAL
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template <typename This, typename F, typename Context>
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struct result<This(F, Context)>
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{
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typedef typename
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remove_reference<
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typename boost::result_of<evaluator(F, Context)>::type
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>::type
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fn;
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typedef typename boost::result_of<fn()>::type type;
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};
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template <typename F, typename Context>
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typename result<function_eval(F const&, Context const&)>::type
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operator()(F const & f, Context const & ctx) const
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{
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return boost::phoenix::eval(f, ctx)();
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}
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template <typename F, typename Context>
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typename result<function_eval(F &, Context const&)>::type
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operator()(F & f, Context const & ctx) const
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{
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return boost::phoenix::eval(f, ctx)();
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}
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#include <boost/phoenix/core/detail/cpp03/function_eval.hpp>
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#else
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template <typename, typename, typename...> struct result_impl;
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template <typename F, typename... A, typename Head, typename... Tail>
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struct result_impl<F, void(A...), Head, Tail...>
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: result_impl<F, void(A..., Head), Tail...>
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{
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};
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template <typename F, typename... A, typename Context>
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struct result_impl<F, void(A...), Context>
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{
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typedef typename
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remove_reference<
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typename boost::result_of<evaluator(F, Context)>::type
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>::type
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fn;
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template <typename T>
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struct result_of_evaluator
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{
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typedef typename boost::add_reference<
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typename boost::add_const<
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typename boost::result_of<
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boost::phoenix::evaluator(T, Context)
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>::type
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>::type
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>::type type;
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};
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typedef typename
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boost::result_of<
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fn(typename result_of_evaluator<A>::type...)
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>::type
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type;
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static type call(F f, A... a, Context ctx)
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{
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return boost::phoenix::eval(f, ctx)(help_rvalue_deduction(boost::phoenix::eval(a, ctx))...);
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}
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};
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template <typename This, typename F, typename... A>
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struct result<This(F, A...)>
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: result_impl<F, void(), A...>
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{
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};
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template <typename F, typename... A>
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typename result<
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function_eval(
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F const &
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, typename mpl::if_<is_reference<A>, A, A const &>::type...
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)
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>::type
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// 'A &... a, Context const &ctx' doesn't work as intended: type deduction always fail.
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operator()(F && f, A &&... a) const
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{
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return
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result<
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function_eval(
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typename mpl::if_<is_reference<F>, F, F const &>::type
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, typename mpl::if_<is_reference<A>, A, A const &>::type...
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)
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>::call(f, a...);
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}
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#endif
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};
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}
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template <typename Dummy>
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struct default_actions::when<detail::rule::function_eval, Dummy>
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: phoenix::call<detail::function_eval>
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{};
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}}
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#endif
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