function_adaptors.hpp

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// Boost Lambda Library -  function_adaptors.hpp ----------------------------
 
// Copyright (C) 1999, 2000 Jaakko Jarvi ([e-mail])
//
// 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_FUNCTION_ADAPTORS_HPP
#define BOOST_LAMBDA_FUNCTION_ADAPTORS_HPP

#include "boost/type_traits/same_traits.hpp"

namespace boost { 
namespace lambda {

template <class Func> struct function_adaptor {

  // we do not know the return type off-hand, we must ask it from Func
  template <class Args> class sig { 
    typedef typename Args::head_type F; 
    typedef typename detail::remove_reference_and_cv<Func>::type plainF;
  public:
    // To sig we pass a cons list, where the head is the function object type
    // itself (potentially cv-qualified)
    // and the tail contains the types of the actual arguments to be passed
    // to the function object. The arguments can be cv qualified
    // as well.
    typedef typename plainF::template sig<Args>::type type;
  };

  template<class RET, class A1>
  static RET apply(A1& a1) {
    return a1();
  }
  template<class RET, class A1, class A2>
  static RET apply(A1& a1, A2& a2) {
    return a1(a2);
  }
  template<class RET, class A1, class A2, class A3>
  static RET apply(A1& a1, A2& a2, A3& a3) {
    return a1(a2, a3);
  }
  template<class RET, class A1, class A2, class A3, class A4>
  static RET apply(A1& a1, A2& a2, A3& a3, A4& a4) {
    return a1(a2, a3, a4);
  }
  template<class RET, class A1, class A2, class A3, class A4, class A5>
  static RET apply(A1& a1, A2& a2, A3& a3, A4& a4, A5& a5) {
    return a1(a2, a3, a4, a5);
  }
  template<class RET, class A1, class A2, class A3, class A4, class A5, class A6>
  static RET apply(A1& a1, A2& a2, A3& a3, A4& a4, A5& a5, A6& a6) {
    return a1(a2, a3, a4, a5, a6);
  }
  template<class RET, class A1, class A2, class A3, class A4, class A5, class A6, 
           class A7>
  static RET apply(A1& a1, A2& a2, A3& a3, A4& a4, A5& a5, A6& a6, 
                           A7& a7) {
    return a1(a2, a3, a4, a5, a6, a7);
  }
  template<class RET, class A1, class A2, class A3, class A4, class A5, class A6, 
           class A7, class A8>
  static RET apply(A1& a1, A2& a2, A3& a3, A4& a4, A5& a5, A6& a6, 
                           A7& a7, A8& a8) {
    return a1(a2, a3, a4, a5, a6, a7, a8);
  }
  template<class RET, class A1, class A2, class A3, class A4, class A5, class A6, 
           class A7, class A8, class A9>
  static RET apply(A1& a1, A2& a2, A3& a3, A4& a4, A5& a5, A6& a6, 
                           A7& a7, A8& a8, A9& a9) {
    return a1(a2, a3, a4, a5, a6, a7, a8, a9);
  }
  template<class RET, class A1, class A2, class A3, class A4, class A5, class A6, 
           class A7, class A8, class A9, class A10>
  static RET apply(A1& a1, A2& a2, A3& a3, A4& a4, A5& a5, A6& a6, 
                           A7& a7, A8& a8, A9& a9, A10& a10) {
    return a1(a2, a3, a4, a5, a6, a7, a8, a9, a10);
  }
};

template <class Func> struct function_adaptor<const Func>; // error 

// -- function adaptors with data member access
template <class Object, class T>
struct function_adaptor<T Object::*> {

  //  typedef detail::unspecified type;

  // T can have qualifiers and can be a reference type
  // We get the return type by adding const, if the object through which
  // the data member is accessed is const, and finally adding a reference
  template<class Args> class sig { 
    typedef typename boost::tuples::element<1, Args>::type argument_type;

    typedef typename detail::IF<boost::is_const<argument_type>::value,
      typename boost::add_const<T>::type,
      T
    >::RET properly_consted_return_type;

    typedef typename detail::IF<
        boost::is_volatile<properly_consted_return_type>::value,
      typename boost::add_volatile<properly_consted_return_type>::type,
      properly_consted_return_type
    >::RET properly_cvd_return_type;


  public:
    typedef typename 
      boost::add_reference<properly_cvd_return_type>::type type;
  };

  template <class RET>
  static RET apply( T Object::*data, Object& o) {
    return o.*data;
  }
  template <class RET>
  static RET apply( T Object::*data, const Object& o) {
    return o.*data;
  }
  template <class RET>
  static RET apply( T Object::*data, volatile Object& o) {
    return o.*data;
  }
  template <class RET>
  static RET apply( T Object::*data, const volatile Object& o) {
    return o.*data;
  }
  template <class RET>
  static RET apply( T Object::*data, Object* o) {
    return o->*data;
  }
  template <class RET>
  static RET apply( T Object::*data, const Object* o) {
    return o->*data;
  }
  template <class RET>
  static RET apply( T Object::*data, volatile Object* o) {
    return o->*data;
  }
  template <class RET>
  static RET apply( T Object::*data, const volatile Object* o) {
    return o->*data;
  }
};

// -- function adaptors with 1 argument apply
   
template <class Result>
struct function_adaptor<Result (void)> {
  
  template<class T> struct sig { typedef Result type; };
  template <class RET>
  static Result apply(Result (*func)()) {
    return func();
  }
};

template <class Result>
struct function_adaptor<Result (*)(void)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET>
  static Result apply(Result (*func)()) {
    return func();
  }
};


// -- function adaptors with 2 argument apply
template <class Object, class Result>
struct function_adaptor<Result (Object::*)() const> {

  template<class T> struct sig { typedef Result type; };
  template <class RET>
  static Result apply( Result (Object::*func)() const, const Object* o) {
    return (o->*func)();
  }
  template <class RET>
  static Result apply( Result (Object::*func)() const, const Object& o) {
    return (o.*func)();
  }
};

template <class Object, class Result>
struct function_adaptor<Result (Object::*)()> {

  template<class T> struct sig { typedef Result type; };
  template <class RET>
  static Result apply( Result (Object::*func)(), Object* o) {
    return (o->*func)();
  }
  template <class RET>
  static Result apply( Result (Object::*func)(), Object& o) {
    return (o.*func)();
  }
};

template <class Arg1, class Result>
struct function_adaptor<Result (Arg1)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1>
  static Result apply(Result (*func)(Arg1), A1& a1) {
    return func(a1);
  }
};

template <class Arg1, class Result>
struct function_adaptor<Result (*)(Arg1)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1>
  static Result apply(Result (*func)(Arg1), A1& a1) {
    return func(a1);
  }
};


// -- function adaptors with 3 argument apply
template <class Object, class Arg1, class Result>
struct function_adaptor<Result (Object::*)(Arg1) const> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1>
  static Result apply( Result (Object::*func)(Arg1) const, const Object* o, 
    A1& a1) {
    return (o->*func)(a1);
  }
  template <class RET, class A1>
  static Result apply( Result (Object::*func)(Arg1) const, const Object& o, 
    A1& a1) {
    return (o.*func)(a1);
  }
};

template <class Object, class Arg1, class Result>
struct function_adaptor<Result (Object::*)(Arg1)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1>
  static Result apply( Result (Object::*func)(Arg1), Object* o, A1& a1) {
    return (o->*func)(a1);
  }
  template <class RET, class A1>
  static Result apply( Result (Object::*func)(Arg1), Object& o, A1& a1) {
    return (o.*func)(a1);
  }
};

template <class Arg1, class Arg2, class Result>
struct function_adaptor<Result (Arg1, Arg2)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1, class A2>
  static Result apply(Result (*func)(Arg1, Arg2), A1& a1, A2& a2) {
    return func(a1, a2);
  }
};

template <class Arg1, class Arg2, class Result>
struct function_adaptor<Result (*)(Arg1, Arg2)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1, class A2>
  static Result apply(Result (*func)(Arg1, Arg2), A1& a1, A2& a2) {
    return func(a1, a2);
  }
};


// -- function adaptors with 4 argument apply
template <class Object, class Arg1, class Arg2, class Result>
struct function_adaptor<Result (Object::*)(Arg1, Arg2) const> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1, class A2>
  static Result apply( Result (Object::*func)(Arg1, Arg2) const, const Object* o, A1& a1, A2& a2) {
    return (o->*func)(a1, a2);
  }
  template <class RET, class A1, class A2>
  static Result apply( Result (Object::*func)(Arg1, Arg2) const, const Object& o, A1& a1, A2& a2) {
    return (o.*func)(a1, a2);
  }
};

template <class Object, class Arg1, class Arg2, class Result>
struct function_adaptor<Result (Object::*)(Arg1, Arg2)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1, class A2>
  static Result apply( Result (Object::*func)(Arg1, Arg2), Object* o, A1& a1, A2& a2) {
    return (o->*func)(a1, a2);
  }
  template <class RET, class A1, class A2>
  static Result apply( Result (Object::*func)(Arg1, Arg2), Object& o, A1& a1, A2& a2) {
    return (o.*func)(a1, a2);
  }
};

template <class Arg1, class Arg2, class Arg3, class Result>
struct function_adaptor<Result (Arg1, Arg2, Arg3)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1, class A2, class A3>
  static Result apply(Result (*func)(Arg1, Arg2, Arg3), A1& a1, A2& a2, A3& a3) {
    return func(a1, a2, a3);
  }
};

template <class Arg1, class Arg2, class Arg3, class Result>
struct function_adaptor<Result (*)(Arg1, Arg2, Arg3)> {

  template<class T> struct sig { typedef Result type; };
  template <class RET, class A1, class A2, class A3>
  static Result apply(Result (*func)(Arg1, Arg2, Arg3), A1& a1, A2& a2, A3& a3) {
    return func(a1, a2, a3);
  }