/*============================================================================= Phoenix V1.2.1 Copyright (c) 2001-2003 Joel de Guzman Use, modification and distribution is subject to 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) ==============================================================================*/ #include #include #include #define PHOENIX_LIMIT 5 #include #include #include #include #include namespace phoenix { /////////////////////////////////////////////////////////////////////////////// // // local_tuple // // This *is a* tuple like the one we see in TupleT in any actor // base class' eval member function. local_tuple should look and // feel the same as a tupled-args, that's why it is derived from // TupleArgsT. It has an added member, locs which is another tuple // where the local variables will be stored. locs is mutable to // allow read-write access to our locals regardless of // local_tuple's constness (The eval member function accepts it as // a const argument). // /////////////////////////////////////////////////////////////////////////////// template struct local_tuple : public TupleArgsT { typedef TupleLocsT local_vars_t; local_tuple(TupleArgsT const& args, TupleLocsT const& locs_) : TupleArgsT(args), locs(locs_) {} mutable TupleLocsT locs; }; /////////////////////////////////////////////////////////////////////////////// // // local_var_result // // This is a return type computer. Given a constant integer N and a // tuple, get the Nth local variable type. If TupleT is not really // a local_tuple, we just return nil_t. Otherwise we get the Nth // local variable type. // /////////////////////////////////////////////////////////////////////////////// template struct local_var_result { typedef nil_t type; }; ////////////////////////////////// template struct local_var_result > { typedef typename tuple_element::type& type; }; /////////////////////////////////////////////////////////////////////////////// // // local_var // // This class looks so curiously like the argument class. local_var // provides access to the Nth local variable packed in the tuple // duo local_tuple above. Note that the member function eval // expects a local_tuple argument. Otherwise the expression // 'tuple.locs' will fail (compile-time error). local_var // primitives only work within the context of a locals_composite // (see below). // // Provided are some predefined local_var actors for 0..N local // variable access: loc1..locN. // /////////////////////////////////////////////////////////////////////////////// template struct local_var { template struct result { typedef typename local_var_result::type type; }; template typename local_var_result::type eval(TupleT const& tuple) const { return tuple.locs[tuple_index()]; } }; ////////////////////////////////// actor > const loc1 = local_var<0>(); actor > const loc2 = local_var<1>(); actor > const loc3 = local_var<2>(); actor > const loc4 = local_var<3>(); actor > const loc5 = local_var<4>(); /////////////////////////////////////////////////////////////////////////////// // // locals_composite // // This class encapsulates an actor and some local variable // initializers packed in a tuple. // // locals_composite is just like a proxy and delegates the actual // evaluation to the actor. The actor does the actual work. In the // eval member function, before invoking the embedded actor's eval // member function, we first stuff an instance of our locals and // bundle both 'args' and 'locals' in a local_tuple. This // local_tuple instance is created in the stack initializing it // with our locals member. We then pass this local_tuple instance // as an argument to the actor's eval member function. // /////////////////////////////////////////////////////////////////////////////// template struct locals_composite { typedef locals_composite self_t; template struct result { typedef typename actor_result::type type; }; locals_composite(ActorT const& actor_, LocsT const& locals_) : actor(actor_), locals(locals_) {} template typename actor_result::type eval(TupleT const& args) const { actor.eval(local_tuple(args, locals)); } ActorT actor; LocsT locals; }; /////////////////////////////////////////////////////////////////////////////// // // locals_gen // // At construction time, this class is given some local var- // initializers packed in a tuple. We just store this for later. // The operator[] of this class creates the actual locals_composite // given an actor. This is responsible for the construct // locals[actor]. // /////////////////////////////////////////////////////////////////////////////// template struct locals_gen { locals_gen(LocsT const& locals_) : locals(locals_) {} template actor::type, LocsT> > operator[](ActorT const& actor) { return locals_composite::type, LocsT> (as_actor::convert(actor), locals); } LocsT locals; }; /////////////////////////////////////////////////////////////////////////////// // // Front end generator functions. These generators are overloaded for // 1..N local variables. locals(i0,...iN) generate locals_gen // objects (see above). // /////////////////////////////////////////////////////////////////////////////// template inline locals_gen > locals( T0 const& _0 = T0() ) { typedef tuple tuple_t; return locals_gen(tuple_t(_0)); } ////////////////////////////////// template inline locals_gen > locals( T0 const& _0 = T0(), T1 const& _1 = T1() ) { typedef tuple tuple_t; return locals_gen(tuple_t(_0, _1)); } ////////////////////////////////// template inline locals_gen > locals( T0 const& _0 = T0(), T1 const& _1 = T1(), T2 const& _2 = T2() ) { typedef tuple tuple_t; return locals_gen(tuple_t(_0, _1, _2)); } ////////////////////////////////// template inline locals_gen > locals( T0 const& _0 = T0(), T1 const& _1 = T1(), T2 const& _2 = T2(), T3 const& _3 = T3() ) { typedef tuple tuple_t; return locals_gen(tuple_t(_0, _1, _2, _3)); } ////////////////////////////////// template inline locals_gen > locals( T0 const& _0 = T0(), T1 const& _1 = T1(), T2 const& _2 = T2(), T3 const& _3 = T3(), T4 const& _4 = T4() ) { typedef tuple tuple_t; return locals_gen(tuple_t(_0, _1, _2, _3, _4)); } /////////////////////////////////////////////////////////////////////////////// } ////////////////////////////////// using namespace std; using namespace phoenix; ////////////////////////////////// int main() { int init[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; vector c(init, init + 10); typedef vector::iterator iterator; for_each(c.begin(), c.end(), locals(0, "...That's all\n") [ for_(loc1 = 0, loc1 < arg1, ++loc1) [ cout << loc1 << ", " ], cout << loc2 ] ); return 0; }