Chris@16: // -- Boost Lambda Library -------------------------------------------------
Chris@16: 
Chris@16: // Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // For more information, see www.boost.org
Chris@16: 
Chris@16: // --------------------------------------------------
Chris@16: 
Chris@16: #ifndef BOOST_LAMBDA_ARITY_CODE_HPP
Chris@16: #define BOOST_LAMBDA_ARITY_CODE_HPP
Chris@16: 
Chris@16: #include "boost/type_traits/cv_traits.hpp"
Chris@16: #include "boost/type_traits/transform_traits.hpp"
Chris@16: 
Chris@16: namespace boost { 
Chris@16: namespace lambda {
Chris@16: 
Chris@16: // These constants state, whether a lambda_functor instantiation results from 
Chris@16: // an expression which contains no placeholders (NONE), 
Chris@16: // only free1 placeholders (FIRST), 
Chris@16: // free2 placeholders and maybe free1 placeholders (SECOND),
Chris@16: // free3 and maybe free1 and free2 placeholders (THIRD),
Chris@16: // freeE placeholders and maybe free1 and free2  (EXCEPTION).
Chris@16: // RETHROW means, that a rethrow expression is used somewhere in the lambda_functor.
Chris@16: 
Chris@16: enum { NONE             = 0x00, // Notice we are using bits as flags here.
Chris@16:        FIRST            = 0x01, 
Chris@16:        SECOND           = 0x02, 
Chris@16:        THIRD            = 0x04, 
Chris@16:        EXCEPTION        = 0x08, 
Chris@16:        RETHROW          = 0x10};
Chris@16: 
Chris@16: 
Chris@16: template<class T>
Chris@16: struct get_tuple_arity;
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template <class T> struct get_arity_;
Chris@16: 
Chris@16: } // end detail;
Chris@16: 
Chris@16: template <class T> struct get_arity {
Chris@16: 
Chris@16:   BOOST_STATIC_CONSTANT(int, value = detail::get_arity_<typename boost::remove_cv<typename boost::remove_reference<T>::type>::type>::value);
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: namespace detail {
Chris@16: 
Chris@16: template<class T>
Chris@16: struct get_arity_ {
Chris@16:   BOOST_STATIC_CONSTANT(int, value = 0);
Chris@16: };
Chris@16: 
Chris@16: template<class T>
Chris@16: struct get_arity_<lambda_functor<T> > {
Chris@16:   BOOST_STATIC_CONSTANT(int, value = get_arity<T>::value);
Chris@16: };
Chris@16: 
Chris@16: template<class Action, class Args>
Chris@16: struct get_arity_<lambda_functor_base<Action, Args> > {
Chris@16:   BOOST_STATIC_CONSTANT(int, value = get_tuple_arity<Args>::value);
Chris@16: };
Chris@16: 
Chris@16: template<int I>
Chris@16: struct get_arity_<placeholder<I> > {
Chris@16:   BOOST_STATIC_CONSTANT(int, value = I);
Chris@16: };
Chris@16: 
Chris@16: } // detail 
Chris@16: 
Chris@16: template<class T>
Chris@16: struct get_tuple_arity {
Chris@16:   BOOST_STATIC_CONSTANT(int, value = get_arity<typename T::head_type>::value | get_tuple_arity<typename T::tail_type>::value);
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template<>
Chris@16: struct get_tuple_arity<null_type> {
Chris@16:   BOOST_STATIC_CONSTANT(int, value = 0);
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16:   // Does T have placeholder<I> as it's subexpression?
Chris@16: 
Chris@16: template<class T, int I>
Chris@16: struct has_placeholder {
Chris@16:   BOOST_STATIC_CONSTANT(bool, value = (get_arity<T>::value & I) != 0);
Chris@16: }; 
Chris@16: 
Chris@16: template<int I, int J>
Chris@16: struct includes_placeholder {
Chris@16:   BOOST_STATIC_CONSTANT(bool, value = (J & I) != 0);
Chris@16: };
Chris@16: 
Chris@16: template<int I, int J>
Chris@16: struct lacks_placeholder {
Chris@16:   BOOST_STATIC_CONSTANT(bool, value = ((J & I) == 0));
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: } // namespace lambda
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif