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