operators.hpp

C++的一个好库。。。现在很流行

                       T&,
                       typename const_copy_argument <T>::type
                     >::RET type;
};

template<class T> struct convert_istream_to_ref_others_to_c_plain_by_default {
  typedef typename detail::IF<
                       is_instance_of_2<
                         T, std::basic_istream
                       >::value,
                       T&,
                       typename const_copy_argument <T>::type
                     >::RET type;
};
#endif

} // detail

BOOST_LAMBDA_BE2(operator<<, bitwise_action< leftshift_action>, A, const B, detail::convert_ostream_to_ref_others_to_c_plain_by_default)
BOOST_LAMBDA_BE2(operator>>, bitwise_action< rightshift_action>, A, const B, detail::convert_istream_to_ref_others_to_c_plain_by_default)      


// special case for io_manipulators.
// function references cannot be given as arguments to lambda operator
// expressions in general. With << and >> the use of manipulators is
// so common, that specializations are provided to make them work.

template<class Arg, class Ret, class ManipArg>
inline const 
lambda_functor<
  lambda_functor_base<
    bitwise_action<leftshift_action>,
    tuple<lambda_functor<Arg>, Ret(&)(ManipArg)> 
  > 
>
operator<<(const lambda_functor<Arg>& a, Ret(&b)(ManipArg))
{
  return 
      lambda_functor_base<
        bitwise_action<leftshift_action>,
        tuple<lambda_functor<Arg>, Ret(&)(ManipArg)>
      > 
    ( tuple<lambda_functor<Arg>, Ret(&)(ManipArg)>(a, b) );
}

template<class Arg, class Ret, class ManipArg>
inline const 
lambda_functor<
  lambda_functor_base<
    bitwise_action<rightshift_action>,
    tuple<lambda_functor<Arg>, Ret(&)(ManipArg)>
  > 
>
operator>>(const lambda_functor<Arg>& a, Ret(&b)(ManipArg))
{
  return 
      lambda_functor_base<
        bitwise_action<rightshift_action>,
        tuple<lambda_functor<Arg>, Ret(&)(ManipArg)>
      > 
    ( tuple<lambda_functor<Arg>, Ret(&)(ManipArg)>(a, b) );
}


// (+ and -) take their arguments as const references. 
// This has consquences with pointer artihmetic
// E.g int a[]; ... *a = 1 works but not *(a+1) = 1. 
// the result of a+1 would be const
// To make the latter work too, 
// non-const arrays are taken as non-const and stored as non-const as well.
#if defined  BOOST_LAMBDA_PTR_ARITHMETIC_E1
#error "Multiple defines of  BOOST_LAMBDA_PTR_ARITHMETIC_E1"
#endif

#define BOOST_LAMBDA_PTR_ARITHMETIC_E1(OPER_NAME, ACTION, CONSTB)            \
template<class Arg, int N, class B>                                         \
inline const                                                                \
lambda_functor<                                                             \
  lambda_functor_base<ACTION, tuple<lambda_functor<Arg>, CONSTB(&)[N]> >   \
>                                                                           \
OPER_NAME (const lambda_functor<Arg>& a, CONSTB(&b)[N])                    \
{                                                                           \
  return lambda_functor<                                                    \
    lambda_functor_base<ACTION, tuple<lambda_functor<Arg>, CONSTB(&)[N]> > \
  >(tuple<lambda_functor<Arg>, CONSTB(&)[N]>(a, b));                       \
}


#if defined  BOOST_LAMBDA_PTR_ARITHMETIC_E2
#error "Multiple defines of  BOOST_LAMBDA_PTR_ARITHMETIC_E2"
#endif

#define BOOST_LAMBDA_PTR_ARITHMETIC_E2(OPER_NAME, ACTION, CONSTA)             \
template<int N, class A, class Arg>                                          \
inline const                                                                 \
lambda_functor<                                                              \
  lambda_functor_base<ACTION, tuple<CONSTA(&)[N], lambda_functor<Arg> > >   \
>                                                                            \
OPER_NAME (CONSTA(&a)[N], const lambda_functor<Arg>& b)                     \
{                                                                            \
  return                                                                     \
    lambda_functor_base<ACTION, tuple<CONSTA(&)[N], lambda_functor<Arg> > > \
    (tuple<CONSTA(&)[N], lambda_functor<Arg> >(a, b));                      \
}


BOOST_LAMBDA_PTR_ARITHMETIC_E1(operator+, arithmetic_action<plus_action>, B)
BOOST_LAMBDA_PTR_ARITHMETIC_E2(operator+, arithmetic_action<plus_action>, A)
BOOST_LAMBDA_PTR_ARITHMETIC_E1(operator+, arithmetic_action<plus_action>,const B)
BOOST_LAMBDA_PTR_ARITHMETIC_E2(operator+, arithmetic_action<plus_action>,const A)


//BOOST_LAMBDA_PTR_ARITHMETIC_E1(operator-, arithmetic_action<minus_action>)
// This is not needed, since the result of ptr-ptr is an rvalue anyway

BOOST_LAMBDA_PTR_ARITHMETIC_E2(operator-, arithmetic_action<minus_action>, A)
BOOST_LAMBDA_PTR_ARITHMETIC_E2(operator-, arithmetic_action<minus_action>, const A)


#undef BOOST_LAMBDA_BE1
#undef BOOST_LAMBDA_BE2
#undef BOOST_LAMBDA_BE3
#undef BOOST_LAMBDA_BE
#undef BOOST_LAMBDA_COMMA_OPERATOR_NAME

#undef BOOST_LAMBDA_PTR_ARITHMETIC_E1
#undef BOOST_LAMBDA_PTR_ARITHMETIC_E2


// ---------------------------------------------------------------------
// unary operators -----------------------------------------------------
// ---------------------------------------------------------------------

#if defined BOOST_LAMBDA_UE
#error "Multiple defines of BOOST_LAMBDA_UE"
#endif

#define BOOST_LAMBDA_UE(OPER_NAME, ACTION)                                 \
template<class Arg>                                                        \
inline const                                                               \
lambda_functor<lambda_functor_base<ACTION, tuple<lambda_functor<Arg> > > > \
OPER_NAME (const lambda_functor<Arg>& a)                                   \
{                                                                          \
  return                                                                   \
    lambda_functor_base<ACTION, tuple<lambda_functor<Arg> > >              \
    ( tuple<lambda_functor<Arg> >(a) );                                    \
}


BOOST_LAMBDA_UE(operator+, unary_arithmetic_action<plus_action>)
BOOST_LAMBDA_UE(operator-, unary_arithmetic_action<minus_action>)
BOOST_LAMBDA_UE(operator~, bitwise_action<not_action>)
BOOST_LAMBDA_UE(operator!, logical_action<not_action>)
BOOST_LAMBDA_UE(operator++, pre_increment_decrement_action<increment_action>)
BOOST_LAMBDA_UE(operator--, pre_increment_decrement_action<decrement_action>)
BOOST_LAMBDA_UE(operator*, other_action<contentsof_action>)
BOOST_LAMBDA_UE(operator&, other_action<addressof_action>)

#if defined BOOST_LAMBDA_POSTFIX_UE
#error "Multiple defines of BOOST_LAMBDA_POSTFIX_UE"
#endif

#define BOOST_LAMBDA_POSTFIX_UE(OPER_NAME, ACTION)                         \
template<class Arg>                                                        \
inline const                                                               \
lambda_functor<lambda_functor_base<ACTION, tuple<lambda_functor<Arg> > > > \
OPER_NAME (const lambda_functor<Arg>& a, int)                              \
{                                                                          \
  return                                                                   \
    lambda_functor_base<ACTION, tuple<lambda_functor<Arg> > >              \
    ( tuple<lambda_functor<Arg> >(a) );                                    \
}


BOOST_LAMBDA_POSTFIX_UE(operator++, post_increment_decrement_action<increment_action>)
BOOST_LAMBDA_POSTFIX_UE(operator--, post_increment_decrement_action<decrement_action>)

#undef BOOST_LAMBDA_UE
#undef BOOST_LAMBDA_POSTFIX_UE

} // namespace lambda
} // namespace boost

#endif