// -- Boost Lambda Library -------------------------------------------------



// Copyright (C) 1999, 2000 Jaakko Järvi (jaakko.jarvi@cs.utu.fi)

//

// 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)

//

// For more information, see www.boost.org



// --------------------------------------------------



#ifndef BOOST_LAMBDA_ARITY_CODE_HPP

#define BOOST_LAMBDA_ARITY_CODE_HPP



#include "boost/type_traits/cv_traits.hpp"

#include "boost/type_traits/transform_traits.hpp"



namespace boost { 

namespace lambda {



// These constants state, whether a lambda_functor instantiation results from 

// an expression which contains no placeholders (NONE), 

// only free1 placeholders (FIRST), 

// free2 placeholders and maybe free1 placeholders (SECOND),

// free3 and maybe free1 and free2 placeholders (THIRD),

// freeE placeholders and maybe free1 and free2  (EXCEPTION).

// RETHROW means, that a rethrow expression is used somewhere in the lambda_functor.



enum { NONE             = 0x00, // Notice we are using bits as flags here.

       FIRST            = 0x01, 

       SECOND           = 0x02, 

       THIRD            = 0x04, 

       EXCEPTION        = 0x08, 

       RETHROW          = 0x10};





template<class T>

struct get_tuple_arity;



namespace detail {



template <class T> struct get_arity_;



} // end detail;



template <class T> struct get_arity {



  BOOST_STATIC_CONSTANT(int, value = detail::get_arity_<typename boost::remove_cv<typename boost::remove_reference<T>::type>::type>::value);



};



namespace detail {



template<class T>

struct get_arity_ {

  BOOST_STATIC_CONSTANT(int, value = 0);

};



template<class T>

struct get_arity_<lambda_functor<T> > {

  BOOST_STATIC_CONSTANT(int, value = get_arity<T>::value);

};



template<class Action, class Args>

struct get_arity_<lambda_functor_base<Action, Args> > {

  BOOST_STATIC_CONSTANT(int, value = get_tuple_arity<Args>::value);

};



template<int I>

struct get_arity_<placeholder<I> > {

  BOOST_STATIC_CONSTANT(int, value = I);

};



} // detail 



template<class T>

struct get_tuple_arity {

  BOOST_STATIC_CONSTANT(int, value = get_arity<typename T::head_type>::value | get_tuple_arity<typename T::tail_type>::value);

};





template<>

struct get_tuple_arity<null_type> {

  BOOST_STATIC_CONSTANT(int, value = 0);

};





  // Does T have placeholder<I> as it's subexpression?



template<class T, int I>

struct has_placeholder {

  BOOST_STATIC_CONSTANT(bool, value = (get_arity<T>::value & I) != 0);

}; 



template<int I, int J>

struct includes_placeholder {

  BOOST_STATIC_CONSTANT(bool, value = (J & I) != 0);

};



template<int I, int J>

struct lacks_placeholder {

  BOOST_STATIC_CONSTANT(bool, value = ((J & I) == 0));

};





} // namespace lambda

} // namespace boost



#endif

