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145 lines
4.5 KiB
145 lines
4.5 KiB
/*============================================================================= |
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Copyright (c) 2001-2007 Joel de Guzman |
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Copyright (c) 2004 Daniel Wallin |
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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 PHOENIX_SCOPE_LET_HPP |
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#define PHOENIX_SCOPE_LET_HPP |
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#include <boost/spirit/home/phoenix/core/limits.hpp> |
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#include <boost/spirit/home/phoenix/core/composite.hpp> |
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#include <boost/spirit/home/phoenix/scope/scoped_environment.hpp> |
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#include <boost/spirit/home/phoenix/scope/detail/local_variable.hpp> |
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#include <boost/spirit/home/phoenix/detail/local_reference.hpp> |
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#include <boost/spirit/home/phoenix/core/actor.hpp> |
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#include <boost/fusion/include/transform.hpp> |
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#include <boost/fusion/include/as_vector.hpp> |
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#include <boost/mpl/eval_if.hpp> |
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#include <boost/mpl/bool.hpp> |
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namespace boost { namespace phoenix |
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{ |
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template <typename Base, typename Vars, typename Map> |
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struct let_actor : Base |
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{ |
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typedef typename |
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mpl::fold< |
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Vars |
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, mpl::false_ |
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, detail::compute_no_nullary |
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>::type |
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no_nullary; |
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template <typename Env> |
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struct result |
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{ |
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typedef typename |
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fusion::result_of::as_vector< |
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typename fusion::result_of::transform< |
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Vars |
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, detail::initialize_local<Env> |
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>::type |
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>::type |
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locals_type; |
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typedef typename Base::template |
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result<scoped_environment<Env, Env, locals_type, Map> >::type |
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result_type; |
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typedef typename |
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detail::unwrap_local_reference<result_type>::type |
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type; |
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}; |
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let_actor(Base const& base, Vars const& vars) |
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: Base(base), vars(vars) {} |
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template <typename Env> |
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typename result<Env>::type |
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eval(Env const& env) const |
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{ |
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typedef typename |
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fusion::result_of::as_vector< |
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typename fusion::result_of::transform< |
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Vars |
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, detail::initialize_local<Env> |
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>::type |
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>::type |
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locals_type; |
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locals_type locals = |
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fusion::as_vector( |
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fusion::transform( |
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vars |
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, detail::initialize_local<Env>(env))); |
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typedef typename result<Env>::type RT; |
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return RT(Base::eval( |
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scoped_environment<Env, Env, locals_type, Map>( |
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env |
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, env |
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, locals))); |
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} |
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Vars vars; |
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}; |
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template <typename Vars, typename Map> |
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struct let_actor_gen |
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{ |
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template <typename Base> |
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actor<let_actor<Base, Vars, Map> > const |
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operator[](actor<Base> const& base) const |
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{ |
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return let_actor<Base, Vars, Map>(base, vars); |
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} |
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let_actor_gen(Vars const& vars) |
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: vars(vars) {} |
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Vars vars; |
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}; |
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template <typename Key> |
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struct local_variable; // forward |
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struct assign_eval; // forward |
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struct let_gen |
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{ |
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template <typename K0, typename V0> |
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let_actor_gen< |
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fusion::vector<V0> |
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, detail::map_local_index_to_tuple<K0> |
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> |
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operator()( |
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actor<composite<assign_eval, fusion::vector<local_variable<K0>, V0> > > const& a0 |
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) const |
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{ |
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return fusion::vector<V0>(fusion::at_c<1>(a0)); |
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} |
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template <typename K0, typename K1, typename V0, typename V1> |
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let_actor_gen< |
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fusion::vector<V0, V1> |
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, detail::map_local_index_to_tuple<K0, K1> |
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> |
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operator()( |
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actor<composite<assign_eval, fusion::vector<local_variable<K0>, V0> > > const& a0 |
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, actor<composite<assign_eval, fusion::vector<local_variable<K1>, V1> > > const& a1 |
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) const |
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{ |
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return fusion::vector<V0, V1>(fusion::at_c<1>(a0), fusion::at_c<1>(a1)); |
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} |
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// Bring in the rest... |
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#define PHOENIX_LOCAL_GEN_NAME let_actor_gen |
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#include <boost/spirit/home/phoenix/scope/detail/local_gen.hpp> |
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#undef PHOENIX_LOCAL_GEN_NAME |
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}; |
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let_gen const let = let_gen(); |
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}} |
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#endif
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