lambda_functor_base.hpp

C++的一个好库。。。现在很流行

// Do nothing --------------------------------------------------------
class do_nothing_action {};

template<class Args>
class lambda_functor_base<do_nothing_action, Args> {
  //  Args args;
public:
  //  explicit lambda_functor_base(const Args& a) {}
  lambda_functor_base() {}


  template<class RET, CALL_TEMPLATE_ARGS> RET call(CALL_FORMAL_ARGS) const {
    return CALL_USE_ARGS;
  }

  template<class SigArgs> struct sig { typedef void type; };
};  


//  These specializatoins provide a shorter notation to define actions.
//  These lambda_functor_base instances take care of the recursive evaluation
//  of the arguments and pass the evaluated arguments to the apply function
//  of an action class. To make action X work with these classes, one must
//  instantiate the lambda_functor_base as:
//  lambda_functor_base<action<ARITY, X>, Args>
//  Where ARITY is the arity of the apply function in X

//  The return type is queried as:
//  return_type_N<X, EvaluatedArgumentTypes>::type
//  for which there must be a specialization.

//  Function actions, casts, throws,... all go via these classes.


template<class Act, class Args>  
class lambda_functor_base<action<0, Act>, Args>           
{  
public:  
//  Args args; not needed
  explicit lambda_functor_base(const Args& a) {}  
  
  template<class SigArgs> struct sig {  
    typedef typename return_type_N<Act, null_type>::type type;
  };
  
  template<class RET, CALL_TEMPLATE_ARGS>  
  RET call(CALL_FORMAL_ARGS) const {  
    CALL_USE_ARGS;
    return Act::template apply<RET>();
  }
};


#if defined BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART  
#error "Multiple defines of BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART"  
#endif  
  
  
#define BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(ARITY)             \
template<class Act, class Args>                                        \
class lambda_functor_base<action<ARITY, Act>, Args>                    \
{                                                                      \
public:                                                                \
  Args args;                                                           \
                                                                       \
  explicit lambda_functor_base(const Args& a) : args(a) {}             \
                                                                       \
  template<class SigArgs> struct sig {                                 \
    typedef typename                                                   \
    detail::deduce_non_ref_argument_types<Args, SigArgs>::type rets_t; \
  public:                                                              \
    typedef typename                                                   \
      return_type_N_prot<Act, rets_t>::type type;                      \
  };                                                                   \
                                                                       \
                                                                       \
  template<class RET, CALL_TEMPLATE_ARGS>                              \
  RET call(CALL_FORMAL_ARGS) const {                                   \
    using boost::tuples::get;                                          \
    using detail::constify_rvals;                                      \
    using detail::r_select;                                            \
    using detail::element_or_null;                                     \
    using detail::deduce_argument_types;                                

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(1)

  typedef typename
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS))
    );
  }
};


BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(2)
  
  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS))
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(3)

  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;

  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS))
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(4)
  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;
  typedef typename element_or_null<3, rets_t>::type rt3;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt3>::go(r_select<rt3>::go(get<3>(args), CALL_ACTUAL_ARGS))
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(5)
  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;
  typedef typename element_or_null<3, rets_t>::type rt3;
  typedef typename element_or_null<4, rets_t>::type rt4;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt3>::go(r_select<rt3>::go(get<3>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt4>::go(r_select<rt4>::go(get<4>(args), CALL_ACTUAL_ARGS))
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(6)

  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;
  typedef typename element_or_null<3, rets_t>::type rt3;
  typedef typename element_or_null<4, rets_t>::type rt4;
  typedef typename element_or_null<5, rets_t>::type rt5;


    return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt3>::go(r_select<rt3>::go(get<3>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt4>::go(r_select<rt4>::go(get<4>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt5>::go(r_select<rt5>::go(get<5>(args), CALL_ACTUAL_ARGS)) 
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(7)
  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;
  typedef typename element_or_null<3, rets_t>::type rt3;
  typedef typename element_or_null<4, rets_t>::type rt4;
  typedef typename element_or_null<5, rets_t>::type rt5;
  typedef typename element_or_null<6, rets_t>::type rt6;


  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt3>::go(r_select<rt3>::go(get<3>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt4>::go(r_select<rt4>::go(get<4>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt5>::go(r_select<rt5>::go(get<5>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt6>::go(r_select<rt6>::go(get<6>(args), CALL_ACTUAL_ARGS))
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(8)
  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;
  typedef typename element_or_null<3, rets_t>::type rt3;
  typedef typename element_or_null<4, rets_t>::type rt4;
  typedef typename element_or_null<5, rets_t>::type rt5;
  typedef typename element_or_null<6, rets_t>::type rt6;
  typedef typename element_or_null<7, rets_t>::type rt7;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt3>::go(r_select<rt3>::go(get<3>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt4>::go(r_select<rt4>::go(get<4>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt5>::go(r_select<rt5>::go(get<5>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt6>::go(r_select<rt6>::go(get<6>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt7>::go(r_select<rt7>::go(get<7>(args), CALL_ACTUAL_ARGS))
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(9)
  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;
  typedef typename element_or_null<3, rets_t>::type rt3;
  typedef typename element_or_null<4, rets_t>::type rt4;
  typedef typename element_or_null<5, rets_t>::type rt5;
  typedef typename element_or_null<6, rets_t>::type rt6;
  typedef typename element_or_null<7, rets_t>::type rt7;
  typedef typename element_or_null<8, rets_t>::type rt8;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt3>::go(r_select<rt3>::go(get<3>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt4>::go(r_select<rt4>::go(get<4>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt5>::go(r_select<rt5>::go(get<5>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt6>::go(r_select<rt6>::go(get<6>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt7>::go(r_select<rt7>::go(get<7>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt8>::go(r_select<rt8>::go(get<8>(args), CALL_ACTUAL_ARGS))
    );
  }
};

BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART(10) 
  typedef typename 
    deduce_argument_types<Args, tuple<CALL_REFERENCE_TYPES> >::type rets_t;
  typedef typename element_or_null<0, rets_t>::type rt0;
  typedef typename element_or_null<1, rets_t>::type rt1;
  typedef typename element_or_null<2, rets_t>::type rt2;
  typedef typename element_or_null<3, rets_t>::type rt3;
  typedef typename element_or_null<4, rets_t>::type rt4;
  typedef typename element_or_null<5, rets_t>::type rt5;
  typedef typename element_or_null<6, rets_t>::type rt6;
  typedef typename element_or_null<7, rets_t>::type rt7;
  typedef typename element_or_null<8, rets_t>::type rt8;
  typedef typename element_or_null<9, rets_t>::type rt9;

  return Act::template apply<RET>(
    constify_rvals<rt0>::go(r_select<rt0>::go(get<0>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt1>::go(r_select<rt1>::go(get<1>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt2>::go(r_select<rt2>::go(get<2>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt3>::go(r_select<rt3>::go(get<3>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt4>::go(r_select<rt4>::go(get<4>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt5>::go(r_select<rt5>::go(get<5>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt6>::go(r_select<rt6>::go(get<6>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt7>::go(r_select<rt7>::go(get<7>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt8>::go(r_select<rt8>::go(get<8>(args), CALL_ACTUAL_ARGS)),
    constify_rvals<rt9>::go(r_select<rt9>::go(get<9>(args), CALL_ACTUAL_ARGS)) 
    );
  }
};

#undef BOOST_LAMBDA_LAMBDA_FUNCTOR_BASE_FIRST_PART


} // namespace lambda
} // namespace boost

#endif