comparison DEPENDENCIES/generic/include/boost/lambda/detail/lambda_traits.hpp @ 16:2665513ce2d3

Add boost headers

+// - lambda_traits.hpp --- Boost Lambda Library ----------------------------
+//
+// 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_LAMBDA_TRAITS_HPP
+#define BOOST_LAMBDA_LAMBDA_TRAITS_HPP
+
+#include "boost/type_traits/transform_traits.hpp"
+#include "boost/type_traits/cv_traits.hpp"
+#include "boost/type_traits/function_traits.hpp"
+#include "boost/type_traits/object_traits.hpp"
+#include "boost/tuple/tuple.hpp"
+
+namespace boost {
+namespace lambda {
+
+// -- if construct ------------------------------------------------
+// Proposed by Krzysztof Czarnecki and Ulrich Eisenecker
+
+namespace detail {
+
+template <bool If, class Then, class Else> struct IF { typedef Then RET; };
+
+template <class Then, class Else> struct IF<false, Then, Else> {
+  typedef Else RET;
+};
+
+
+// An if construct that doesn't instantiate the non-matching template:
+
+// Called as: 
+//  IF_type<condition, A, B>::type 
+// The matching template must define the typeded 'type'
+// I.e. A::type if condition is true, B::type if condition is false
+// Idea from Vesa Karvonen (from C&E as well I guess)
+template<class T>
+struct IF_type_
+{
+  typedef typename T::type type;
+};
+
+
+template<bool C, class T, class E>
+struct IF_type
+{
+  typedef typename
+    IF_type_<typename IF<C, T, E>::RET >::type type;
+};
+
+// helper that can be used to give typedef T to some type
+template <class T> struct identity_mapping { typedef T type; };
+
+// An if construct for finding an integral constant 'value'
+// Does not instantiate the non-matching branch
+// Called as IF_value<condition, A, B>::value
+// If condition is true A::value must be defined, otherwise B::value
+
+template<class T>
+struct IF_value_
+{
+  BOOST_STATIC_CONSTANT(int, value = T::value);
+};
+
+
+template<bool C, class T, class E>
+struct IF_value
+{
+  BOOST_STATIC_CONSTANT(int, value = (IF_value_<typename IF<C, T, E>::RET>::value));
+};
+
+
+// --------------------------------------------------------------
+
+// removes reference from other than function types:
+template<class T> class remove_reference_if_valid
+{
+
+  typedef typename boost::remove_reference<T>::type plainT;
+public:
+  typedef typename IF<
+    boost::is_function<plainT>::value,
+    T,
+    plainT
+  >::RET type;
+
+};
+
+
+template<class T> struct remove_reference_and_cv {
+   typedef typename boost::remove_cv<
+     typename boost::remove_reference<T>::type
+   >::type type;
+};
+
+
+   
+// returns a reference to the element of tuple T
+template<int N, class T> struct tuple_element_as_reference {   
+  typedef typename
+     boost::tuples::access_traits<
+       typename boost::tuples::element<N, T>::type
+     >::non_const_type type;
+};
+
+// returns the cv and reverence stripped type of a tuple element
+template<int N, class T> struct tuple_element_stripped {   
+  typedef typename
+     remove_reference_and_cv<
+       typename boost::tuples::element<N, T>::type
+     >::type type;
+};
+
+// is_lambda_functor -------------------------------------------------   
+
+template <class T> struct is_lambda_functor_ {
+  BOOST_STATIC_CONSTANT(bool, value = false);
+};
+   
+template <class Arg> struct is_lambda_functor_<lambda_functor<Arg> > {
+  BOOST_STATIC_CONSTANT(bool, value = true);
+};
+   
+} // end detail
+
+   
+template <class T> struct is_lambda_functor {
+  BOOST_STATIC_CONSTANT(bool, 
+     value = 
+       detail::is_lambda_functor_<
+         typename detail::remove_reference_and_cv<T>::type
+       >::value);
+};
+   
+
+namespace detail {
+
+// -- parameter_traits_ ---------------------------------------------
+
+// An internal parameter type traits class that respects
+// the reference_wrapper class.
+
+// The conversions performed are:
+// references -> compile_time_error
+// T1 -> T2, 
+// reference_wrapper<T> -> T&
+// const array -> ref to const array
+// array -> ref to array
+// function -> ref to function
+
+// ------------------------------------------------------------------------
+
+template<class T1, class T2> 
+struct parameter_traits_ {
+  typedef T2 type;
+};
+
+// Do not instantiate with reference types
+template<class T, class Any> struct parameter_traits_<T&, Any> {
+  typedef typename 
+    generate_error<T&>::
+      parameter_traits_class_instantiated_with_reference_type type;
+};
+
+// Arrays can't be stored as plain types; convert them to references
+template<class T, int n, class Any> struct parameter_traits_<T[n], Any> {
+  typedef T (&type)[n];
+};
+   
+template<class T, int n, class Any> 
+struct parameter_traits_<const T[n], Any> {
+  typedef const T (&type)[n];
+};
+
+template<class T, int n, class Any> 
+struct parameter_traits_<volatile T[n], Any> {
+  typedef volatile  T (&type)[n];
+};
+template<class T, int n, class Any> 
+struct parameter_traits_<const volatile T[n], Any> {
+  typedef const volatile T (&type)[n];
+};
+
+
+template<class T, class Any> 
+struct parameter_traits_<boost::reference_wrapper<T>, Any >{
+  typedef T& type;
+};
+
+template<class T, class Any> 
+struct parameter_traits_<const boost::reference_wrapper<T>, Any >{
+  typedef T& type;
+};
+
+template<class T, class Any> 
+struct parameter_traits_<volatile boost::reference_wrapper<T>, Any >{
+  typedef T& type;
+};
+
+template<class T, class Any> 
+struct parameter_traits_<const volatile boost::reference_wrapper<T>, Any >{
+  typedef T& type;
+};
+
+template<class Any>
+struct parameter_traits_<void, Any> {
+  typedef void type;
+};
+
+template<class Arg, class Any>
+struct parameter_traits_<lambda_functor<Arg>, Any > {
+  typedef lambda_functor<Arg> type;
+};
+
+template<class Arg, class Any>
+struct parameter_traits_<const lambda_functor<Arg>, Any > {
+  typedef lambda_functor<Arg> type;
+};
+
+// Are the volatile versions needed?
+template<class Arg, class Any>
+struct parameter_traits_<volatile lambda_functor<Arg>, Any > {
+  typedef lambda_functor<Arg> type;
+};
+
+template<class Arg, class Any>
+struct parameter_traits_<const volatile lambda_functor<Arg>, Any > {
+  typedef lambda_functor<Arg> type;
+};
+
+} // end namespace detail
+
+
+// ------------------------------------------------------------------------
+// traits classes for lambda expressions (bind functions, operators ...)   
+
+// must be instantiated with non-reference types
+
+// The default is const plain type -------------------------
+// const T -> const T, 
+// T -> const T, 
+// references -> compile_time_error
+// reference_wrapper<T> -> T&
+// array -> const ref array
+template<class T>
+struct const_copy_argument {
+  typedef typename 
+    detail::parameter_traits_<
+      T,
+      typename detail::IF<boost::is_function<T>::value, T&, const T>::RET
+    >::type type;
+};
+
+// T may be a function type. Without the IF test, const would be added 
+// to a function type, which is illegal.
+
+// all arrays are converted to const.
+// This traits template is used for 'const T&' parameter passing 
+// and thus the knowledge of the potential 
+// non-constness of an actual argument is lost.   
+template<class T, int n>  struct const_copy_argument <T[n]> {
+  typedef const T (&type)[n];
+};
+template<class T, int n>  struct const_copy_argument <volatile T[n]> {
+     typedef const volatile T (&type)[n];
+};
+   
+template<class T>
+struct const_copy_argument<T&> {};
+// do not instantiate with references
+  //  typedef typename detail::generate_error<T&>::references_not_allowed type;
+
+
+template<>
+struct const_copy_argument<void> {
+  typedef void type;
+};
+
+
+// Does the same as const_copy_argument, but passes references through as such
+template<class T>
+struct bound_argument_conversion {
+  typedef typename const_copy_argument<T>::type type; 
+};
+
+template<class T>
+struct bound_argument_conversion<T&> {
+  typedef T& type; 
+};
+   
+// The default is non-const reference -------------------------
+// const T -> const T&, 
+// T -> T&, 
+// references -> compile_time_error
+// reference_wrapper<T> -> T&
+template<class T>
+struct reference_argument {
+  typedef typename detail::parameter_traits_<T, T&>::type type; 
+};
+
+template<class T>
+struct reference_argument<T&> {
+  typedef typename detail::generate_error<T&>::references_not_allowed type; 
+};
+
+template<class Arg>
+struct reference_argument<lambda_functor<Arg> > {
+  typedef lambda_functor<Arg> type;
+};
+
+template<class Arg>
+struct reference_argument<const lambda_functor<Arg> > {
+  typedef lambda_functor<Arg> type;
+};
+
+// Are the volatile versions needed?
+template<class Arg>
+struct reference_argument<volatile lambda_functor<Arg> > {
+  typedef lambda_functor<Arg> type;
+};
+
+template<class Arg>
+struct reference_argument<const volatile lambda_functor<Arg> > {
+  typedef lambda_functor<Arg> type;
+};
+
+template<>
+struct reference_argument<void> {
+  typedef void type;
+};
+
+namespace detail {
+   
+// Array to pointer conversion
+template <class T>
+struct array_to_pointer { 
+  typedef T type;
+};
+
+template <class T, int N>
+struct array_to_pointer <const T[N]> { 
+  typedef const T* type;
+};
+template <class T, int N>
+struct array_to_pointer <T[N]> { 
+  typedef T* type;
+};
+
+template <class T, int N>
+struct array_to_pointer <const T (&) [N]> { 
+  typedef const T* type;
+};
+template <class T, int N>
+struct array_to_pointer <T (&) [N]> { 
+  typedef T* type;
+};
+
+
+// ---------------------------------------------------------------------------
+// The call_traits for bind
+// Respects the reference_wrapper class.
+
+// These templates are used outside of bind functions as well.
+// the bind_tuple_mapper provides a shorter notation for default
+// bound argument storing semantics, if all arguments are treated
+// uniformly.
+
+// from template<class T> foo(const T& t) : bind_traits<const T>::type
+// from template<class T> foo(T& t) : bind_traits<T>::type
+
+// Conversions:
+// T -> const T,
+// cv T -> cv T, 
+// T& -> T& 
+// reference_wrapper<T> -> T&
+// const reference_wrapper<T> -> T&
+// array -> const ref array
+
+// make bound arguments const, this is a deliberate design choice, the
+// purpose is to prevent side effects to bound arguments that are stored
+// as copies
+template<class T>
+struct bind_traits {
+  typedef const T type; 
+};
+
+template<class T>
+struct bind_traits<T&> {
+  typedef T& type; 
+};
+
+// null_types are an exception, we always want to store them as non const
+// so that other templates can assume that null_type is always without const
+template<>
+struct bind_traits<null_type> {
+  typedef null_type type;
+};
+
+// the bind_tuple_mapper, bind_type_generators may 
+// introduce const to null_type
+template<>
+struct bind_traits<const null_type> {
+  typedef null_type type;
+};
+
+// Arrays can't be stored as plain types; convert them to references.
+// All arrays are converted to const. This is because bind takes its
+// parameters as const T& and thus the knowledge of the potential 
+// non-constness of actual argument is lost.
+template<class T, int n>  struct bind_traits <T[n]> {
+  typedef const T (&type)[n];
+};
+
+template<class T, int n> 
+struct bind_traits<const T[n]> {
+  typedef const T (&type)[n];
+};
+
+template<class T, int n>  struct bind_traits<volatile T[n]> {
+  typedef const volatile T (&type)[n];
+};
+
+template<class T, int n> 
+struct bind_traits<const volatile T[n]> {
+  typedef const volatile T (&type)[n];
+};
+
+template<class R>
+struct bind_traits<R()> {
+    typedef R(&type)();
+};
+
+template<class R, class Arg1>
+struct bind_traits<R(Arg1)> {
+    typedef R(&type)(Arg1);
+};
+
+template<class R, class Arg1, class Arg2>
+struct bind_traits<R(Arg1, Arg2)> {
+    typedef R(&type)(Arg1, Arg2);
+};
+
+template<class R, class Arg1, class Arg2, class Arg3>
+struct bind_traits<R(Arg1, Arg2, Arg3)> {
+    typedef R(&type)(Arg1, Arg2, Arg3);
+};
+
+template<class R, class Arg1, class Arg2, class Arg3, class Arg4>
+struct bind_traits<R(Arg1, Arg2, Arg3, Arg4)> {
+    typedef R(&type)(Arg1, Arg2, Arg3, Arg4);
+};
+
+template<class R, class Arg1, class Arg2, class Arg3, class Arg4, class Arg5>
+struct bind_traits<R(Arg1, Arg2, Arg3, Arg4, Arg5)> {
+    typedef R(&type)(Arg1, Arg2, Arg3, Arg4, Arg5);
+};
+
+template<class R, class Arg1, class Arg2, class Arg3, class Arg4, class Arg5, class Arg6>
+struct bind_traits<R(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6)> {
+    typedef R(&type)(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6);
+};
+
+template<class R, class Arg1, class Arg2, class Arg3, class Arg4, class Arg5, class Arg6, class Arg7>
+struct bind_traits<R(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7)> {
+    typedef R(&type)(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7);
+};
+
+template<class R, class Arg1, class Arg2, class Arg3, class Arg4, class Arg5, class Arg6, class Arg7, class Arg8>
+struct bind_traits<R(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8)> {
+    typedef R(&type)(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8);
+};
+
+template<class R, class Arg1, class Arg2, class Arg3, class Arg4, class Arg5, class Arg6, class Arg7, class Arg8, class Arg9>
+struct bind_traits<R(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, Arg9)> {
+    typedef R(&type)(Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, Arg9);
+};
+
+template<class T> 
+struct bind_traits<reference_wrapper<T> >{
+  typedef T& type;
+};
+
+template<class T> 
+struct bind_traits<const reference_wrapper<T> >{
+  typedef T& type;
+};
+
+template<>
+struct bind_traits<void> {
+  typedef void type;
+};
+
+
+
+template <
+  class T0 = null_type, class T1 = null_type, class T2 = null_type, 
+  class T3 = null_type, class T4 = null_type, class T5 = null_type, 
+  class T6 = null_type, class T7 = null_type, class T8 = null_type, 
+  class T9 = null_type
+>
+struct bind_tuple_mapper {
+  typedef
+    tuple<typename bind_traits<T0>::type, 
+          typename bind_traits<T1>::type, 
+          typename bind_traits<T2>::type, 
+          typename bind_traits<T3>::type, 
+          typename bind_traits<T4>::type, 
+          typename bind_traits<T5>::type, 
+          typename bind_traits<T6>::type, 
+          typename bind_traits<T7>::type,
+          typename bind_traits<T8>::type,
+          typename bind_traits<T9>::type> type;
+};
+
+// bind_traits, except map const T& -> const T
+  // this is needed e.g. in currying. Const reference arguments can
+  // refer to temporaries, so it is not safe to store them as references.
+  template <class T> struct remove_const_reference {
+    typedef typename bind_traits<T>::type type;
+  };
+
+  template <class T> struct remove_const_reference<const T&> {
+    typedef const T type;
+  };
+
+
+// maps the bind argument types to the resulting lambda functor type
+template <
+  class T0 = null_type, class T1 = null_type, class T2 = null_type, 
+  class T3 = null_type, class T4 = null_type, class T5 = null_type, 
+  class T6 = null_type, class T7 = null_type, class T8 = null_type, 
+  class T9 = null_type
+>
+class bind_type_generator {
+
+  typedef typename
+  detail::bind_tuple_mapper<
+    T0, T1, T2, T3, T4, T5, T6, T7, T8, T9
+  >::type args_t;
+
+  BOOST_STATIC_CONSTANT(int, nof_elems = boost::tuples::length<args_t>::value);
+
+  typedef 
+    action<
+      nof_elems, 
+      function_action<nof_elems>
+    > action_type;
+
+public:
+  typedef
+    lambda_functor<
+      lambda_functor_base<
+        action_type, 
+        args_t
+      >
+    > type; 
+    
+};
+
+
+   
+} // detail
+   
+template <class T> inline const T&  make_const(const T& t) { return t; }
+
+
+} // end of namespace lambda
+} // end of namespace boost
+
+
+   
+#endif // BOOST_LAMBDA_TRAITS_HPP