/*=============================================================================
    Phoenix V1.0
    Copyright (c) 2001-2002 Joel de Guzman

    Permission to copy, use, modify, sell and distribute this software
    is granted provided this copyright notice appears in all copies.
    This software is provided "as is" without express or implied
    warranty, and with no claim as to its suitability for any purpose.
==============================================================================*/
#ifndef PHOENIX_PRIMITIVES_HPP
#define PHOENIX_PRIMITIVES_HPP

///////////////////////////////////////////////////////////////////////////////
#include "boost/spirit/phoenix/actor.hpp"

///////////////////////////////////////////////////////////////////////////////
namespace phoenix {

///////////////////////////////////////////////////////////////////////////////
//
//  argument class
//
//      Lazy arguments
//
//      An actor base class that extracts and returns the Nth argument
//      from the argument list passed in the 'args' tuple in the eval
//      member function (see actor.hpp). There are some predefined
//      argument constants that can be used as actors (arg1..argN).
//
//      The argument actor is a place-holder for the actual arguments
//      passed by the client. For example, wherever arg1 is seen placed
//      in a lazy function (see functions.hpp) or lazy operator (see
//      operators.hpp), this will be replaced by the actual first
//      argument in the actual function evaluation. Argument actors are
//      essentially lazy arguments. A lazy argument is a full actor in
//      its own right and can be evaluated through the actor's operator().
//
//      Example:
//
//          char        c = 'A';
//          int         i = 123;
//          const char* s = "Hello World";
//
//          cout << arg1(c) << ' ';
//          cout << arg1(i, s) << ' ';
//          cout << arg2(i, s) << ' ';
//
//       will print out "A 123 Hello World"
//
///////////////////////////////////////////////////////////////////////////////
template <int N>
struct argument {

    template <typename TupleT>
    struct result { typedef typename tuple_element<N, TupleT>::type type; };

    template <typename TupleT>
    typename tuple_element<N, TupleT>::type
    eval(TupleT const& args) const
    {
        return args[tuple_index<N>()];
    }
};

//////////////////////////////////
actor<argument<0> > const arg1 = argument<0>();
actor<argument<1> > const arg2 = argument<1>();
actor<argument<2> > const arg3 = argument<2>();

#if PHOENIX_LIMIT > 3
actor<argument<3> > const arg4 = argument<3>();
actor<argument<4> > const arg5 = argument<4>();
actor<argument<5> > const arg6 = argument<5>();

#if PHOENIX_LIMIT > 6
actor<argument<6> > const arg7 = argument<6>();
actor<argument<7> > const arg8 = argument<7>();
actor<argument<8> > const arg9 = argument<8>();

#if PHOENIX_LIMIT > 9
actor<argument<9> > const arg10 = argument<9>();
actor<argument<10> > const arg11 = argument<10>();
actor<argument<11> > const arg12 = argument<11>();

#if PHOENIX_LIMIT > 12
actor<argument<12> > const arg13 = argument<12>();
actor<argument<13> > const arg14 = argument<13>();
actor<argument<14> > const arg15 = argument<14>();

#endif
#endif
#endif
#endif
///////////////////////////////////////////////////////////////////////////////
//
//  value class
//
//      Lazy values
//
//      A bound actual parameter is kept in a value class for deferred
//      access later when needed. A value object is immutable. Value
//      objects are typically created through the val(x) free function
//      which returns a value<T> with T deduced from the type of x. x is
//      held in the value<T> object by value.
//
//      Lazy values are actors. As such, lazy values can be evaluated
//      through the actor's operator(). Such invocation gives the value's
//      identity. Example:
//
//          cout << val(3)() << val("Hello World")();
//
//      prints out "3 Hello World"
//
///////////////////////////////////////////////////////////////////////////////
template <typename T>
struct value {

    typedef typename boost::remove_reference<T>::type plain_t;

    template <typename TupleT>
    struct result { typedef plain_t const type; };

    value(plain_t val_)
    :   val(val_) {}

    template <typename TupleT>
    plain_t const
    eval(TupleT const& /*args*/) const
    {
        return val;
    }

    plain_t val;
};

//////////////////////////////////
template <typename T>
inline actor<value<T> > const
val(T v)
{
    return value<T>(v);
}

//////////////////////////////////
template <typename BaseT>
void
val(actor<BaseT> const& v);     //  This is undefined and not allowed.

///////////////////////////////////////////////////////////////////////////
//
//  Arbitrary types T are typically converted to a actor<value<T> >
//  (see as_actor<T> in actor.hpp). A specialization is also provided
//  for arrays. T[N] arrays are converted to actor<value<T const*> >.
//
///////////////////////////////////////////////////////////////////////////
template <typename T>
struct as_actor {

    typedef actor<value<T> > type;
    static type convert(T const& x)
    { return value<T>(x); }
};

//////////////////////////////////
template <typename T, int N>
struct as_actor<T[N]> {

    typedef actor<value<T const*> > type;
    static type convert(T const x[N])
    { return value<T const*>(x); }
};

///////////////////////////////////////////////////////////////////////////////
//
//  variable class
//
//      Lazy variables
//
//      A bound actual parameter may also be held by non-const reference
//      in a variable class for deferred access later when needed. A
//      variable object is mutable, i.e. its referenced variable can be
//      modified. Variable objects are typically created through the
//      var(x) free function which returns a variable<T> with T deduced
//      from the type of x. x is held in the value<T> object by
//      reference.
//
//      Lazy variables are actors. As such, lazy variables can be
//      evaluated through the actor's operator(). Such invocation gives
//      the variables's identity. Example:
//
//          int i = 3;
//          char const* s = "Hello World";
//          cout << var(i)() << var(s)();
//
//      prints out "3 Hello World"
//
//      Another free function const_(x) may also be used. const_(x) creates
//      a variable<T const&> object using a constant reference.
//
///////////////////////////////////////////////////////////////////////////////
template <typename T>
struct variable {

    template <typename TupleT>
    struct result { typedef T& type; };

    variable(T& var_)
    :   var(var_) {}

    template <typename TupleT>
    T&
    eval(TupleT const& /*args*/) const
    {
        return var;
    }

    T& var;
};

//////////////////////////////////
template <typename T>
inline actor<variable<T> > const
var(T& v)
{
    return variable<T>(v);
}

//////////////////////////////////
template <typename T>
inline actor<variable<T const> > const
const_(T const& v)
{
    return variable<T const>(v);
}

//////////////////////////////////
template <typename BaseT>
void
var(actor<BaseT> const& v);     //  This is undefined and not allowed.

//////////////////////////////////
template <typename BaseT>
void
const_(actor<BaseT> const& v);  //  This is undefined and not allowed.

///////////////////////////////////////////////////////////////////////////////
}   //  namespace phoenix

#endif
