type_list.h

/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2025 John Wellbelove
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
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******************************************************************************/
 
#ifndef ETL_TYPE_LIST_INCLUDED
#define ETL_TYPE_LIST_INCLUDED
 
#include "platform.h"
 
#include "index_of_type.h"
#include "integral_limits.h"
#include "largest.h"
#include "static_assert.h"
#include "type_traits.h"
#include "utility.h"
 
#if ETL_USING_CPP11
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  static ETL_CONSTANT size_t type_list_npos = etl::integral_limits<size_t>::max;
 
  //***************************************************************************
  // Type list forward declaration.
  //***************************************************************************
  template <typename... TTypes>
  struct type_list;
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  struct is_type_list : etl::false_type
  {
  };
 
  template <typename... TTypes>
  struct is_type_list<etl::type_list<TTypes...>> : etl::true_type
  {
  };
 
  #if ETL_USING_CPP17
  template <typename T>
  inline constexpr bool is_type_list_v = is_type_list<T>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <>
  struct type_list<>
  {
    static constexpr size_t size = 0U;
 
    using index_sequence_type = etl::make_index_sequence<0>; 
 
  private:
 
    // A type_list cannot be instantiated, so delete the constructor and
    // assignment operators.
    type_list() ETL_DELETE;
    type_list(const type_list&) ETL_DELETE;
    type_list& operator=(const type_list&) ETL_DELETE;
  };
 
  namespace private_type_list
  {
    // helper to solve the issue that recursed-rest can't be put directly in
    // type_list::tail definition
    template <typename... TTypes>
    struct recursion_helper
    {
      using type = type_list<TTypes...>;
    };
  } // namespace private_type_list
 
  //***************************************************************************
  //***************************************************************************
  template <typename THead, typename... TTail>
  struct type_list<THead, TTail...> : type_list<TTail...>
  {
    using head = THead;
    using tail = typename private_type_list::recursion_helper<TTail...>::type;
 
    static constexpr size_t size = sizeof...(TTail) + 1U;
 
    using index_sequence_type = etl::make_index_sequence< sizeof...(TTail) + 1U>; 
 
  private:
 
    // A type_list cannot be instantiated, so delete the constructor and
    // assignment operators.
    type_list() ETL_DELETE;
    type_list(const type_list&) ETL_DELETE;
    type_list& operator=(const type_list&) ETL_DELETE;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename THead>
  struct type_list<THead> : type_list<>
  {
    using head = THead;
    using tail = typename private_type_list::recursion_helper<>::type;
 
    static constexpr size_t size = 1U;
 
    using index_sequence_type = etl::make_index_sequence<1>; 
 
  private:
 
    type_list() ETL_DELETE;
    type_list(const type_list&) ETL_DELETE;
    type_list& operator=(const type_list&) ETL_DELETE;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypes>
  struct type_list_size;
 
  template <typename... TTypes>
  struct type_list_size<etl::type_list<TTypes...>> : public etl::integral_constant<size_t, sizeof...(TTypes)>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename... TTypes>
  inline constexpr size_t type_list_size_v = type_list_size<etl::type_list<TTypes...>>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, size_t Index>
  struct type_list_type_at_index
  {
    ETL_STATIC_ASSERT(Index < TTypeList::size, "etl::type_list_type_at_index out of range");
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
 
    using type = typename type_list_type_at_index<typename TTypeList::tail, Index - 1>::type;
  };
 
  template <typename TTypeList>
  struct type_list_type_at_index<TTypeList, 0>
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
 
    using type = typename TTypeList::head;
  };
 
  template <typename TTypeList, size_t Index>
  using type_list_type_at_index_t = typename type_list_type_at_index<TTypeList, Index>::type;
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, typename T>
  struct type_list_index_of_type
    : public etl::integral_constant< size_t, etl::is_same<typename TTypeList::head, T>::value
                                               ? 0
                                               : (type_list_index_of_type<typename TTypeList::tail, T>::value == etl::type_list_npos
                                                    ? etl::type_list_npos
                                                    : type_list_index_of_type<typename TTypeList::tail, T>::value + 1)>
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
  };
 
  template <typename T>
  struct type_list_index_of_type<type_list<>, T> : public etl::integral_constant<size_t, etl::type_list_npos>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, typename T>
  inline constexpr size_t type_list_index_of_v = etl::type_list_index_of_type<TTypeList, T>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  namespace private_type_list
  {
    template <typename TTypeList, typename T, size_t Index, typename TResult>
    struct type_list_indices_of_type_impl;
 
    // The general case, check the head type, then recurse with the rest of the
    // types.
    template <typename Head, typename... Tail, typename T, size_t Index, typename TResult>
    struct type_list_indices_of_type_impl<etl::type_list<Head, Tail...>, T, Index, TResult>
    {
    private:
 
      // If Head is the same as T then append a new index to the result,
      // otherwise no change.
      using next_result = etl::conditional_t<etl::is_same<Head, T>::value, etl::index_sequence_push_back_t<TResult, Index>, TResult>;
 
    public:
 
      // Recurse with the rest of the type_list, passing on the current result.
      using type = typename type_list_indices_of_type_impl<etl::type_list<Tail...>, T, Index + 1U, next_result>::type;
    };
 
    // Specialisation for an empty type_list.
    // This is the terminating specialisation for the general case.
    template <typename T, size_t Index, typename TResult>
    struct type_list_indices_of_type_impl<etl::type_list<>, T, Index, TResult>
    {
      using type = TResult;
    };
  } // namespace private_type_list
 
  template <typename TTypeList, typename T>
  struct type_list_indices_of_type
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
 
    using type = typename private_type_list::type_list_indices_of_type_impl< TTypeList, T, 0U, etl::index_sequence<>>::type;
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList, typename T>
  using type_list_indices_of_type_t = typename type_list_indices_of_type<TTypeList, T>::type;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, typename T>
  struct type_list_contains;
 
  template <typename T, typename... TTypes>
  struct type_list_contains<etl::type_list<TTypes...>, T> : public etl::integral_constant<bool, etl::is_one_of<T, TTypes...>::value>
  {
  };
 
  template <typename T>
  struct type_list_contains<type_list<>, T> : public etl::integral_constant<bool, false>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, typename T>
  inline constexpr bool type_list_contains_v = etl::type_list_contains<TTypeList, T>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, typename T>
  struct type_list_has_duplicates_of;
 
  template <typename T, typename... TTypes>
  struct type_list_has_duplicates_of<etl::type_list<TTypes...>, T> : public etl::has_duplicates_of<T, TTypes...>
  {
  };
 
  template <typename T>
  struct type_list_has_duplicates_of<type_list<>, T> : public etl::integral_constant<bool, false>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, typename T>
  inline constexpr bool type_list_has_duplicates_of_v = etl::type_list_has_duplicates_of<TTypeList, T>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, typename T>
  struct type_list_count_of;
 
  template <typename T, typename... TTypes>
  struct type_list_count_of<etl::type_list<TTypes...>, T> : public etl::count_of<T, TTypes...>
  {
  };
 
  template <typename T>
  struct type_list_count_of<type_list<>, T> : public etl::integral_constant<size_t, 0>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, typename T>
  inline constexpr size_t type_list_count_of_v = etl::type_list_count_of<TTypeList, T>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  struct type_list_max_size;
 
  template <typename... TTypes>
  struct type_list_max_size<etl::type_list<TTypes...>> : public etl::integral_constant<size_t, etl::largest<TTypes...>::size>
  {
  };
 
  template <>
  struct type_list_max_size<type_list<>> : public etl::integral_constant<size_t, 0>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList>
  inline constexpr size_t type_list_max_size_v = etl::type_list_max_size<TTypeList>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  struct type_list_max_alignment;
 
  template <typename... TTypes>
  struct type_list_max_alignment<etl::type_list<TTypes...>> : public etl::integral_constant<size_t, etl::largest<TTypes...>::alignment>
  {
  };
 
  template <>
  struct type_list_max_alignment<type_list<>> : public etl::integral_constant<size_t, 1>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList>
  inline constexpr size_t type_list_max_alignment_v = etl::type_list_max_alignment<TTypeList>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, size_t... Indices>
  struct type_list_select
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
 
    using type = type_list<type_list_type_at_index_t<TTypeList, Indices>...>;
  };
 
  template <typename TTypeList, size_t... Indices>
  using type_list_select_t = typename type_list_select<TTypeList, Indices...>::type;
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, typename TIndexSequence>
  struct type_list_select_from_index_sequence;
 
  template <typename TTypeList, size_t... Indices>
  struct type_list_select_from_index_sequence<TTypeList, etl::index_sequence<Indices...>>
  {
    using type = etl::type_list_select_t<TTypeList, Indices...>;
  };
 
  template <typename TTypeList, typename TIndexSequence>
  using type_list_select_from_index_sequence_t = typename type_list_select_from_index_sequence<TTypeList, TIndexSequence>::type;
 
  //***************************************************************************
  //***************************************************************************
  template <typename... TTypes>
  struct type_list_cat;
 
  template <typename... TTypes1, typename... TTypes2, typename... TTail>
  struct type_list_cat<etl::type_list<TTypes1...>, etl::type_list<TTypes2...>, TTail...>
  {
    using type = typename type_list_cat<etl::type_list<TTypes1..., TTypes2...>, TTail...>::type;
  };
 
  template <typename T>
  struct type_list_cat<T>
  {
    using type = T;
  };
 
  template <typename... TypeLists>
  using type_list_cat_t = typename type_list_cat<TypeLists...>::type;
 
  //***************************************************************************
  //***************************************************************************
  template <typename T, typename... TTypes>
  struct type_list_push_front;
 
  template <typename T, typename... TTypes>
  struct type_list_push_front<etl::type_list<TTypes...>, T>
  {
    using type = type_list<T, TTypes...>;
  };
 
  template <typename TypeList, typename T>
  using type_list_push_front_t = typename type_list_push_front<TypeList, T>::type;
 
  //***************************************************************************
  //***************************************************************************
  template <typename T, typename... TTypes>
  struct type_list_push_back;
 
  template <typename T, typename... TTypes>
  struct type_list_push_back<etl::type_list<TTypes...>, T>
  {
    using type = type_list<TTypes..., T>;
  };
 
  template <typename TypeList, typename T>
  using type_list_push_back_t = typename type_list_push_back<TypeList, T>::type;
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, typename T, size_t Index>
  struct type_list_insert
  {
  private:
 
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
    ETL_STATIC_ASSERT(Index <= TTypeList::size, "Index out of range");
 
    using index_sequence_for_prefix = etl::make_index_sequence<Index>;
    using index_sequence_for_suffix = etl::make_index_sequence_with_offset<Index, TTypeList::size - Index>;
 
    using prefix = etl::type_list_select_from_index_sequence_t<TTypeList, index_sequence_for_prefix>;
    using suffix = etl::type_list_select_from_index_sequence_t<TTypeList, index_sequence_for_suffix>;
 
  public:
 
    // Concatenate the prefix, new type, and suffix to create the new type list
    // with T inserted at the correct position.
    using type = etl::type_list_cat_t<prefix, etl::type_list<T>, suffix>;
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList, typename T, size_t Index>
  using type_list_insert_t = typename etl::type_list_insert<TTypeList, T, Index>::type;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, size_t Index>
  struct type_list_remove
  {
  private:
 
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
    ETL_STATIC_ASSERT(Index < TTypeList::size, "Index out of range");
 
    using index_sequence_for_prefix = etl::make_index_sequence<Index>;
    using index_sequence_for_suffix = etl::make_index_sequence_with_offset<Index + 1, TTypeList::size - Index - 1>;
 
    using prefix = etl::type_list_select_from_index_sequence_t<TTypeList, index_sequence_for_prefix>;
    using suffix = etl::type_list_select_from_index_sequence_t<TTypeList, index_sequence_for_suffix>;
 
  public:
 
    // Concatenate the prefix and suffix to create the new type list with the
    // Index element removed.
    using type = etl::type_list_cat_t<prefix, suffix>;
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList, size_t Index>
  using type_list_remove_t = typename etl::type_list_remove<TTypeList, Index>::type;
  #endif
 
  //***************************************************************************
  // Remove types that satisfy a predicate from a type_list.
  //***************************************************************************
  namespace private_type_list
  {
    template <typename TTypeList, template <typename> class TPredicate>
    struct type_list_remove_if_impl;
 
    template <template <typename> class TPredicate>
    struct type_list_remove_if_impl<etl::type_list<>, TPredicate>
    {
      using type = etl::type_list<>;
    };
 
    template <typename Head, typename... Tail, template <typename> class TPredicate>
    struct type_list_remove_if_impl<etl::type_list<Head, Tail...>, TPredicate>
    {
    private:
 
      using rest = typename type_list_remove_if_impl<etl::type_list<Tail...>, TPredicate>::type;
 
    public:
 
      using type = typename etl::conditional< TPredicate<Head>::value, rest, etl::type_list_push_front_t<rest, Head>>::type;
    };
  } // namespace private_type_list
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, template <typename> class TPredicate>
  struct type_list_remove_if
  {
  private:
 
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
 
  public:
 
    using type = typename private_type_list::type_list_remove_if_impl<TTypeList, TPredicate>::type;
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList, template <typename> class TPredicate>
  using type_list_remove_if_t = typename etl::type_list_remove_if<TTypeList, TPredicate>::type;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList>
  struct type_list_pop_front
  {
  private:
 
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
    ETL_STATIC_ASSERT(TTypeList::size > 0U, "Cannot pop_front from an empty type_list");
 
  public:
 
    using type = typename TTypeList::tail;
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList>
  using type_list_pop_front_t = typename etl::type_list_pop_front<TTypeList>::type;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList>
  struct type_list_pop_back
  {
  private:
 
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
    ETL_STATIC_ASSERT(TTypeList::size > 0U, "Cannot pop_back from an empty type_list");
 
  public:
 
    using type = typename etl::type_list_remove<TTypeList, TTypeList::size - 1U>::type;
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList>
  using type_list_pop_back_t = typename etl::type_list_pop_back<TTypeList>::type;
  #endif
 
  //***************************************************************************
  // Remove duplicate types from a type_list, preserving the first occurrence.
  //***************************************************************************
  namespace private_type_list
  {
    template <typename TTypeList, typename TResult>
    struct type_list_unique_impl;
 
    // Base case: empty list, return the result.
    template <typename TResult>
    struct type_list_unique_impl<etl::type_list<>, TResult>
    {
      using type = TResult;
    };
 
    // Recursive case: Check if the head is already in the result, if not add
    // it, then recurse on the tail.
    template <typename Head, typename... Tail, typename TResult>
    struct type_list_unique_impl<etl::type_list<Head, Tail...>, TResult>
    {
    private:
 
      using next_result = etl::conditional_t<etl::type_list_contains<TResult, Head>::value, TResult, etl::type_list_push_back_t<TResult, Head>>;
 
    public:
 
      using type = typename type_list_unique_impl<etl::type_list<Tail...>, next_result>::type;
    };
  } // namespace private_type_list
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList>
  struct type_list_unique
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
 
    using type = typename private_type_list::type_list_unique_impl<TTypeList, etl::type_list<>>::type;
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList>
  using type_list_unique_t = typename etl::type_list_unique<TTypeList>::type;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList>
  struct type_list_is_unique
    // Create a unique version of the type list, and check if it is the same as
    // the original list. If they are the same, then all types in the original
    // list are unique.
    : etl::bool_constant< etl::is_same< TTypeList, typename type_list_unique<TTypeList>::type>::value>
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList>
  inline constexpr bool type_list_is_unique_v = etl::type_list_is_unique<TTypeList>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  struct type_list_is_empty;
 
  template <>
  struct type_list_is_empty<etl::type_list<>> : etl::true_type
  {
  };
 
  template <typename... TTypes>
  struct type_list_is_empty<etl::type_list<TTypes...>> : etl::false_type
  {
  };
 
  #if ETL_USING_CPP17
  template <typename... TTypes>
  inline constexpr bool type_list_is_empty_v = type_list_is_empty<TTypes...>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, template <typename> class TPredicate>
  struct type_list_all_of;
 
  template <template <typename> class TPredicate, typename... TTypes>
  struct type_list_all_of<etl::type_list<TTypes...>, TPredicate> : etl::conjunction<TPredicate<TTypes>...>
  {
  };
 
  template <template <typename> class TPredicate>
  struct type_list_all_of<etl::type_list<>, TPredicate> : etl::bool_constant<true>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, template <typename> class TPredicate>
  inline constexpr bool type_list_all_of_v = type_list_all_of<TTypeList, TPredicate>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, template <typename> class TPredicate>
  struct type_list_any_of;
 
  template <template <typename> class TPredicate, typename... TTypes>
  struct type_list_any_of<etl::type_list<TTypes...>, TPredicate> : etl::disjunction<TPredicate<TTypes>...>
  {
  };
 
  template <template <typename> class TPredicate>
  struct type_list_any_of<etl::type_list<>, TPredicate> : etl::bool_constant<false>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, template <typename> class TPredicate>
  inline constexpr bool type_list_any_of_v = type_list_any_of<TTypeList, TPredicate>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename TTypeList, template <typename> class TPredicate>
  struct type_list_none_of;
 
  template <template <typename> class TPredicate, typename... TTypes>
  struct type_list_none_of<etl::type_list<TTypes...>, TPredicate> : etl::negation<etl::disjunction<TPredicate<TTypes>...>>
  {
  };
 
  template <template <typename> class TPredicate>
  struct type_list_none_of<etl::type_list<>, TPredicate> : etl::bool_constant<true>
  {
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, template <typename> class TPredicate>
  inline constexpr bool type_list_none_of_v = type_list_none_of<TTypeList, TPredicate>::value;
  #endif
 
  //***************************************************************************
  //***************************************************************************
  // Primary template
  template <typename TFromList, typename TToList>
  struct type_lists_are_convertible;
 
  // Specialization: both lists empty, convertible
  template <>
  struct type_lists_are_convertible<etl::type_list<>, etl::type_list<>> : public etl::true_type
  {
  };
 
  // Recursive case: check head types, then recurse
  template <typename TFromHead, typename... TFromTail, typename TToHead, typename... TToTail>
  struct type_lists_are_convertible<etl::type_list<TFromHead, TFromTail...>, etl::type_list<TToHead, TToTail...>>
    : public etl::bool_constant< etl::is_convertible<TFromHead, TToHead>::value
                                 && etl::type_lists_are_convertible< etl::type_list<TFromTail...>, etl::type_list<TToTail...>>::value>
  {
    static_assert(sizeof...(TFromTail) == sizeof...(TToTail), "Type lists are not the same length");
  };
 
  #if ETL_USING_CPP17
  template <typename TFromList, typename TToList>
  inline constexpr bool type_lists_are_convertible_v = etl::type_lists_are_convertible<TFromList, TToList>::value;
  #endif
 
  namespace private_type_list
  {
    //*********************************
    template <typename TTypeList, template <typename, typename> class TCompare>
    struct type_list_is_sorted_impl;
 
    //*********************************
    // Empty list is sorted
    template <template <typename, typename> class TCompare>
    struct type_list_is_sorted_impl<etl::type_list<>, TCompare> : etl::true_type
    {
    };
 
    //*********************************
    // Single element list is sorted
    template <typename T0, template <typename, typename> class TCompare>
    struct type_list_is_sorted_impl<etl::type_list<T0>, TCompare> : etl::true_type
    {
    };
 
    //*********************************
    // Ensure that the list is sorted.
    // Recursively compare the head to the next element to ensure that the list
    // is sorted.
    template <typename Head, typename Next, typename... Tail, template <typename, typename> class TCompare>
    struct type_list_is_sorted_impl<etl::type_list<Head, Next, Tail...>, TCompare>
      : etl::bool_constant< !TCompare<Next, Head>::value && type_list_is_sorted_impl< etl::type_list<Next, Tail...>, TCompare>::value>
    {
    };
  } // namespace private_type_list
 
  //*****************************************************************************
  //*****************************************************************************
  template <typename TTypeList, template <typename, typename> class TCompare>
  struct type_list_is_sorted : public private_type_list::type_list_is_sorted_impl<TTypeList, TCompare>
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
  };
 
  #if ETL_USING_CPP17
  template <typename TTypeList, template <typename, typename> class TCompare>
  inline constexpr bool type_list_is_sorted_v = etl::type_list_is_sorted<TTypeList, TCompare>::value;
  #endif
 
  //*****************************************************************************
  namespace private_type_list
  {
    //*********************************
    template <bool InsertBefore, typename Head, typename T, template <typename, typename> class TCompare, typename... Tail>
    struct insert_sorted_impl;
 
    //*********************************
    template <typename TSortedList, typename T, template <typename, typename> class TCompare>
    struct type_list_insert_sorted_impl;
 
    //*********************************
    // Insert T into sorted list using TCompare
    // Empty list -> T becomes the list
    template <typename T, template <typename, typename> class TCompare>
    struct type_list_insert_sorted_impl<etl::type_list<>, T, TCompare>
    {
      using type = etl::type_list<T>;
    };
 
    //*********************************
    // Insert T into the correct position in the sorted list, as determined by
    // TCompare
    template <typename Head, typename... Tail, typename T, template <typename, typename> class TCompare>
    struct type_list_insert_sorted_impl<etl::type_list<Head, Tail...>, T, TCompare>
    {
      using type = typename insert_sorted_impl<TCompare<T, Head>::value, Head, T, TCompare, Tail...>::type;
    };
 
    //*********************************
    // If InsertBefore is true, then T should be inserted before Head
    template <typename Head, typename T, template <typename, typename> class TCompare, typename... Tail>
    struct insert_sorted_impl<true, Head, T, TCompare, Tail...>
    {
      using type = etl::type_list<T, Head, Tail...>;
    };
 
    //*********************************
    // If InsertBefore is false, then T should be inserted after Head, so we
    // recursively call insert_sorted_impl on the tail of the list
    template <typename Head, typename T, template <typename, typename> class TCompare, typename... Tail>
    struct insert_sorted_impl<false, Head, T, TCompare, Tail...>
    {
      using type = etl::type_list_push_front_t< typename type_list_insert_sorted_impl<etl::type_list<Tail...>, T, TCompare>::type, Head>;
    };
  } // namespace private_type_list
 
  //*****************************************************************************
  //*****************************************************************************
  template <typename TTypeList, typename T, template <typename, typename> class TCompare>
  struct type_list_insert_sorted : public private_type_list::type_list_insert_sorted_impl<TTypeList, T, TCompare>
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
    ETL_STATIC_ASSERT((etl::type_list_is_sorted<TTypeList, TCompare>::value), "Cannot insert into a non-sorted type list");
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList, typename T, template <typename, typename> class TCompare>
  using type_list_insert_sorted_t = typename etl::type_list_insert_sorted<TTypeList, T, TCompare>::type;
  #endif
 
  //***************************************************************************
  namespace private_type_list
  {
    //*********************************
    // Forward declaration
    template <typename TTypeList, template <typename, typename> class TCompare>
    struct type_list_sort_impl;
 
    //*********************************
    // Empty list
    template <template <typename, typename> class TCompare>
    struct type_list_sort_impl<etl::type_list<>, TCompare>
    {
      using type = etl::type_list<>;
    };
 
    //*********************************
    // Single element list
    template <typename T0, template <typename, typename> class TCompare>
    struct type_list_sort_impl<etl::type_list<T0>, TCompare>
    {
      using type = etl::type_list<T0>;
    };
 
    //*********************************
    // Define a new type_list by sorting the types according to TCompare
    template <typename Head, typename... Tail, template <typename, typename> class TCompare>
    struct type_list_sort_impl<etl::type_list<Head, Tail...>, TCompare>
    {
    private:
 
      using sorted_tail = typename type_list_sort_impl<etl::type_list<Tail...>, TCompare>::type;
 
    public:
 
      using type = typename etl::type_list_insert_sorted<sorted_tail, Head, TCompare>::type;
    };
  } // namespace private_type_list
 
  //*****************************************************************************
  //*****************************************************************************
  template <typename TTypeList, template <typename, typename> class TCompare>
  struct type_list_sort : public private_type_list::type_list_sort_impl<TTypeList, TCompare>
  {
    ETL_STATIC_ASSERT((etl::is_type_list<TTypeList>::value), "TTypeList must be an etl::type_list");
  };
 
  #if ETL_USING_CPP11
  template <typename TTypeList, template <typename, typename> class TCompare>
  using type_list_sort_t = typename etl::type_list_sort<TTypeList, TCompare>::type;
  #endif
} // namespace etl
#endif
 
#endif