Chris@16: /*=============================================================================
Chris@16:     Phoenix V1.2.1
Chris@16:     Copyright (c) 2001-2002 Joel de Guzman
Chris@16: 
Chris@16:   Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16:   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: ==============================================================================*/
Chris@16: #ifndef PHOENIX_PRIMITIVES_HPP
Chris@16: #define PHOENIX_PRIMITIVES_HPP
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: #include <boost/spirit/home/classic/phoenix/actor.hpp>
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: namespace phoenix {
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: //  argument class
Chris@16: //
Chris@16: //      Lazy arguments
Chris@16: //
Chris@16: //      An actor base class that extracts and returns the Nth argument
Chris@16: //      from the argument list passed in the 'args' tuple in the eval
Chris@16: //      member function (see actor.hpp). There are some predefined
Chris@16: //      argument constants that can be used as actors (arg1..argN).
Chris@16: //
Chris@16: //      The argument actor is a place-holder for the actual arguments
Chris@16: //      passed by the client. For example, wherever arg1 is seen placed
Chris@16: //      in a lazy function (see functions.hpp) or lazy operator (see
Chris@16: //      operators.hpp), this will be replaced by the actual first
Chris@16: //      argument in the actual function evaluation. Argument actors are
Chris@16: //      essentially lazy arguments. A lazy argument is a full actor in
Chris@16: //      its own right and can be evaluated through the actor's operator().
Chris@16: //
Chris@16: //      Example:
Chris@16: //
Chris@16: //          char        c = 'A';
Chris@16: //          int         i = 123;
Chris@16: //          const char* s = "Hello World";
Chris@16: //
Chris@16: //          cout << arg1(c) << ' ';
Chris@16: //          cout << arg1(i, s) << ' ';
Chris@16: //          cout << arg2(i, s) << ' ';
Chris@16: //
Chris@16: //       will print out "A 123 Hello World"
Chris@16: //
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: template <int N>
Chris@16: struct argument {
Chris@16: 
Chris@16:     template <typename TupleT>
Chris@16:     struct result { typedef typename tuple_element<N, TupleT>::type type; };
Chris@16: 
Chris@16:     template <typename TupleT>
Chris@16:     typename tuple_element<N, TupleT>::type
Chris@16:     eval(TupleT const& args) const
Chris@16:     {
Chris@16:         return args[tuple_index<N>()];
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: actor<argument<0> > const arg1 = argument<0>();
Chris@16: actor<argument<1> > const arg2 = argument<1>();
Chris@16: actor<argument<2> > const arg3 = argument<2>();
Chris@16: 
Chris@16: #if PHOENIX_LIMIT > 3
Chris@16: actor<argument<3> > const arg4 = argument<3>();
Chris@16: actor<argument<4> > const arg5 = argument<4>();
Chris@16: actor<argument<5> > const arg6 = argument<5>();
Chris@16: 
Chris@16: #if PHOENIX_LIMIT > 6
Chris@16: actor<argument<6> > const arg7 = argument<6>();
Chris@16: actor<argument<7> > const arg8 = argument<7>();
Chris@16: actor<argument<8> > const arg9 = argument<8>();
Chris@16: 
Chris@16: #if PHOENIX_LIMIT > 9
Chris@16: actor<argument<9> > const arg10 = argument<9>();
Chris@16: actor<argument<10> > const arg11 = argument<10>();
Chris@16: actor<argument<11> > const arg12 = argument<11>();
Chris@16: 
Chris@16: #if PHOENIX_LIMIT > 12
Chris@16: actor<argument<12> > const arg13 = argument<12>();
Chris@16: actor<argument<13> > const arg14 = argument<13>();
Chris@16: actor<argument<14> > const arg15 = argument<14>();
Chris@16: 
Chris@16: #endif
Chris@16: #endif
Chris@16: #endif
Chris@16: #endif
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: //  value class
Chris@16: //
Chris@16: //      Lazy values
Chris@16: //
Chris@16: //      A bound actual parameter is kept in a value class for deferred
Chris@16: //      access later when needed. A value object is immutable. Value
Chris@16: //      objects are typically created through the val(x) free function
Chris@16: //      which returns a value<T> with T deduced from the type of x. x is
Chris@16: //      held in the value<T> object by value.
Chris@16: //
Chris@16: //      Lazy values are actors. As such, lazy values can be evaluated
Chris@16: //      through the actor's operator(). Such invocation gives the value's
Chris@16: //      identity. Example:
Chris@16: //
Chris@16: //          cout << val(3)() << val("Hello World")();
Chris@16: //
Chris@16: //      prints out "3 Hello World"
Chris@16: //
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: template <typename T>
Chris@16: struct value {
Chris@16: 
Chris@16:     typedef typename boost::remove_reference<T>::type plain_t;
Chris@16: 
Chris@16:     template <typename TupleT>
Chris@16:     struct result { typedef plain_t const type; };
Chris@16: 
Chris@16:     value(plain_t val_)
Chris@16:     :   val(val_) {}
Chris@16: 
Chris@16:     template <typename TupleT>
Chris@16:     plain_t const
Chris@16:     eval(TupleT const& /*args*/) const
Chris@16:     {
Chris@16:         return val;
Chris@16:     }
Chris@16: 
Chris@16:     plain_t val;
Chris@16: };
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: template <typename T>
Chris@16: inline actor<value<T> > const
Chris@16: val(T v)
Chris@16: {
Chris@16:     return value<T>(v);
Chris@16: }
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: template <typename BaseT>
Chris@16: void
Chris@16: val(actor<BaseT> const& v);     //  This is undefined and not allowed.
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: //  Arbitrary types T are typically converted to a actor<value<T> >
Chris@16: //  (see as_actor<T> in actor.hpp). A specialization is also provided
Chris@16: //  for arrays. T[N] arrays are converted to actor<value<T const*> >.
Chris@16: //
Chris@16: ///////////////////////////////////////////////////////////////////////////
Chris@16: template <typename T>
Chris@16: struct as_actor {
Chris@16: 
Chris@16:     typedef actor<value<T> > type;
Chris@16:     static type convert(T const& x)
Chris@16:     { return value<T>(x); }
Chris@16: };
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: template <typename T, int N>
Chris@16: struct as_actor<T[N]> {
Chris@16: 
Chris@16:     typedef actor<value<T const*> > type;
Chris@16:     static type convert(T const x[N])
Chris@16:     { return value<T const*>(x); }
Chris@16: };
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: //  variable class
Chris@16: //
Chris@16: //      Lazy variables
Chris@16: //
Chris@16: //      A bound actual parameter may also be held by non-const reference
Chris@16: //      in a variable class for deferred access later when needed. A
Chris@16: //      variable object is mutable, i.e. its referenced variable can be
Chris@16: //      modified. Variable objects are typically created through the
Chris@16: //      var(x) free function which returns a variable<T> with T deduced
Chris@16: //      from the type of x. x is held in the value<T> object by
Chris@16: //      reference.
Chris@16: //
Chris@16: //      Lazy variables are actors. As such, lazy variables can be
Chris@16: //      evaluated through the actor's operator(). Such invocation gives
Chris@16: //      the variables's identity. Example:
Chris@16: //
Chris@16: //          int i = 3;
Chris@16: //          char const* s = "Hello World";
Chris@16: //          cout << var(i)() << var(s)();
Chris@16: //
Chris@16: //      prints out "3 Hello World"
Chris@16: //
Chris@16: //      Another free function const_(x) may also be used. const_(x) creates
Chris@16: //      a variable<T const&> object using a constant reference.
Chris@16: //
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
Chris@16: #pragma warning(push)
Chris@16: #pragma warning(disable:4512) //assignment operator could not be generated
Chris@16: #endif
Chris@16: 
Chris@16: template <typename T>
Chris@16: struct variable {
Chris@16: 
Chris@16:     template <typename TupleT>
Chris@16:     struct result { typedef T& type; };
Chris@16: 
Chris@16:     variable(T& var_)
Chris@16:     :   var(var_) {}
Chris@16: 
Chris@16:     template <typename TupleT>
Chris@16:     T&
Chris@16:     eval(TupleT const& /*args*/) const
Chris@16:     {
Chris@16:         return var;
Chris@16:     }
Chris@16: 
Chris@16:     T& var;
Chris@16: };
Chris@16: 
Chris@16: #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
Chris@16: #pragma warning(pop)
Chris@16: #endif
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: template <typename T>
Chris@16: inline actor<variable<T> > const
Chris@16: var(T& v)
Chris@16: {
Chris@16:     return variable<T>(v);
Chris@16: }
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: template <typename T>
Chris@16: inline actor<variable<T const> > const
Chris@16: const_(T const& v)
Chris@16: {
Chris@16:     return variable<T const>(v);
Chris@16: }
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: template <typename BaseT>
Chris@16: void
Chris@16: var(actor<BaseT> const& v);     //  This is undefined and not allowed.
Chris@16: 
Chris@16: //////////////////////////////////
Chris@16: template <typename BaseT>
Chris@16: void
Chris@16: const_(actor<BaseT> const& v);  //  This is undefined and not allowed.
Chris@16: 
Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: }   //  namespace phoenix
Chris@16: 
Chris@16: #endif