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- // -- Boost Lambda Library -------------------------------------------------
- // Copyright (C) 1999, 2000 Jaakko Jarvi (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
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