From c2bd4e61bde6d978885f4aba34a07bf3554f58b2 Mon Sep 17 00:00:00 2001
From: Amar Mahmutbegovic <amar.mahmutbegovic@gmail.com>
Date: Sat, 11 Jan 2025 18:46:30 +0100
Subject: [PATCH] add boost::sml example

---
 Chapter17/fsm/CMakeLists.txt                  |    3 +-
 Chapter17/fsm/app/src/main_fsm_boost_sml.cpp  |   92 +
 Chapter17/fsm/app/src/main_fsm_simple.cpp     |    4 +-
 .../fsm/app/src/main_fsm_state_pattern.cpp    |  174 +
 Chapter17/fsm/libs/boost/sml.hpp              | 2900 +++++++++++++++++
 5 files changed, 3170 insertions(+), 3 deletions(-)
 create mode 100644 Chapter17/fsm/app/src/main_fsm_boost_sml.cpp
 create mode 100644 Chapter17/fsm/app/src/main_fsm_state_pattern.cpp
 create mode 100644 Chapter17/fsm/libs/boost/sml.hpp

diff --git a/Chapter17/fsm/CMakeLists.txt b/Chapter17/fsm/CMakeLists.txt
index 3d9410c..8e88ab0 100644
--- a/Chapter17/fsm/CMakeLists.txt
+++ b/Chapter17/fsm/CMakeLists.txt
@@ -89,6 +89,7 @@ include_directories(
   ${CMAKE_SOURCE_DIR}/hal/adc/inc
   ${CMAKE_SOURCE_DIR}/cstdlib_support
   ${CMAKE_SOURCE_DIR}/util/inc
+  ${CMAKE_SOURCE_DIR}/libs/boost
   )
 
 set(EXECUTABLE ${PROJECT_NAME}.elf)
@@ -130,8 +131,6 @@ target_link_options(
   -mthumb
   ${LIB_SPECS}
   -lnosys
-  -u
-  _printf_float
   -lc
   -lm
   -Wl,--no-warn-rwx-segments
diff --git a/Chapter17/fsm/app/src/main_fsm_boost_sml.cpp b/Chapter17/fsm/app/src/main_fsm_boost_sml.cpp
new file mode 100644
index 0000000..6fe8b76
--- /dev/null
+++ b/Chapter17/fsm/app/src/main_fsm_boost_sml.cpp
@@ -0,0 +1,92 @@
+#include <cstdint>
+#include <cstdio>
+
+#include <functional>
+
+#include <stm32f072xb.h>
+
+#include <hal.hpp>
+#include <stm32f0xx_hal_uart.hpp>
+#include <uart_stm32.hpp>
+
+#include <retarget.hpp>
+
+#include <cassert>
+
+#include "sml.hpp"
+
+namespace sml = boost::sml;
+
+struct ble_button_pressed{};
+struct connection_request{};
+struct timer_expired{};
+
+constexpr auto start_advertising = [](){
+    printf("Action: start_advertising()\n");
+};
+
+constexpr auto stop_advertising = [](){
+    printf("Action: stop_advertising()\n");
+};
+
+constexpr auto disconnect = [](){
+    printf("Action: disconnect()\n");
+};
+
+struct ble_fsm {
+  auto operator()() const {
+    using namespace sml;
+    /**
+     * Initial state: *initial_state
+     * Transition DSL: src_state + event [ guard ] / action = dst_state
+     */
+    return make_transition_table(
+      *"idle"_s + event<ble_button_pressed>         / start_advertising = "advertising"_s,
+       "advertising"_s  + event<connection_request>                     = "connected"_s,
+       "advertising"_s  + event<timer_expired>      / stop_advertising  = "idle"_s,
+       "connected"_s + event<ble_button_pressed>    / disconnect        = "idle"_s
+    );
+  }
+};
+
+int main()
+{
+    hal::init();
+
+    hal::uart_stm32<hal::stm32::uart> uart(USART2);
+    uart.init();
+
+    retarget::set_stdio_uart(&uart);
+
+    using namespace sml;
+
+    sm<ble_fsm> my_ble_fsm{}; 
+
+    const auto print_current_state = [&]() {
+        printf("Current State: ");
+        if(my_ble_fsm.is("idle"_s)) {
+            printf("idle\n");
+        } 
+        if(my_ble_fsm.is("advertising"_s)) {
+            printf("advertising\n");
+        } 
+        if(my_ble_fsm.is("connected"_s)) {
+            printf("connected\n");
+        } 
+    };
+
+    print_current_state();
+
+    my_ble_fsm.process_event(ble_button_pressed{});
+    print_current_state();
+
+    my_ble_fsm.process_event(connection_request{});
+    print_current_state();
+
+    my_ble_fsm.process_event(ble_button_pressed{});
+    print_current_state();
+
+    while(true)
+    {
+    }
+}
diff --git a/Chapter17/fsm/app/src/main_fsm_simple.cpp b/Chapter17/fsm/app/src/main_fsm_simple.cpp
index 029e5c4..98fe6ff 100644
--- a/Chapter17/fsm/app/src/main_fsm_simple.cpp
+++ b/Chapter17/fsm/app/src/main_fsm_simple.cpp
@@ -74,7 +74,8 @@ private:
     }
 };
 
-static const char* state_to_string(ble_state state) {
+namespace {
+const char* state_to_string(ble_state state) {
     switch (state) {
         case ble_state::idle:        return "idle";
         case ble_state::advertising: return "advertising";
@@ -82,6 +83,7 @@ static const char* state_to_string(ble_state state) {
         default:                     return "unknown";
     }
 }
+}
 
 int main()
 {
diff --git a/Chapter17/fsm/app/src/main_fsm_state_pattern.cpp b/Chapter17/fsm/app/src/main_fsm_state_pattern.cpp
new file mode 100644
index 0000000..aa64523
--- /dev/null
+++ b/Chapter17/fsm/app/src/main_fsm_state_pattern.cpp
@@ -0,0 +1,174 @@
+#include <cstdint>
+#include <cstdio>
+
+#include <functional>
+
+#include <stm32f072xb.h>
+
+#include <hal.hpp>
+#include <stm32f0xx_hal_uart.hpp>
+#include <uart_stm32.hpp>
+
+#include <retarget.hpp>
+
+#include "etl/vector.h"
+
+enum class ble_state {
+    idle,
+    advertising,
+    connected
+};
+
+enum class ble_event {
+    ble_button_pressed,
+    connection_request,
+    timer_expired
+};
+
+class state {
+public:
+    virtual ble_state handle_event(ble_event event) = 0;
+    virtual ble_state get_state_enum() = 0;
+};
+
+class idle : public state{
+public:
+    ble_state handle_event(ble_event event) {
+        if (event == ble_event::ble_button_pressed) {
+            start_advertising();
+            return ble_state::advertising;
+        }
+        return get_state_enum();
+    }
+    ble_state get_state_enum() {
+       return ble_state::idle; 
+    }
+private:
+    void start_advertising() {
+        printf("Action: start_advertising()\n");
+    }
+};
+
+class advertising : public state{
+public:
+    ble_state handle_event(ble_event event) {
+        if (event == ble_event::connection_request) {
+            return ble_state::connected;
+        }
+        if (event == ble_event::timer_expired) {
+            stop_advertising();
+            return ble_state::idle;
+        }
+        return get_state_enum();
+    }
+    ble_state get_state_enum() {
+       return ble_state::advertising; 
+    }
+private:
+    void stop_advertising() {
+        printf("Action: stop_advertising()\n");
+    }
+};
+
+class connected : public state{
+public:
+    ble_state handle_event(ble_event event) {
+        if (event == ble_event::ble_button_pressed) {
+            disconnect();
+            return ble_state::idle;
+        }
+        return get_state_enum();
+    }
+    ble_state get_state_enum() {
+       return ble_state::connected; 
+    }
+private:
+    void disconnect() {
+        printf("Action: disconnect()\n");
+    }
+};
+
+class ble_fsm {
+public:
+    void handle_event(ble_event event) {
+        if(auto the_state = get_the_state(current_state_)) {
+            current_state_ = the_state->handle_event(event);
+        }
+    }
+
+    ble_state get_state() const {
+        return current_state_;
+    }
+
+    void add_state(state *the_state) {
+        states_.push_back(the_state);
+    }
+
+private:
+    std::vector<state*> states_;
+    ble_state current_state_ = ble_state::idle;
+
+    state* get_the_state(ble_state state_enum) {
+        const auto is_state_enum = [&] (state *the_state) {
+            return the_state->get_state_enum() == state_enum;
+        };
+        auto it = std::find_if(states_.begin(), states_.end(), is_state_enum);
+
+        if(it != states_.end()) {
+            return *it;
+        }
+        return nullptr;
+    }
+};
+
+namespace {
+const char* state_to_string(ble_state state) {
+    switch (state) {
+        case ble_state::idle:        return "idle";
+        case ble_state::advertising: return "advertising";
+        case ble_state::connected:   return "connected";
+        default:                     return "unknown";
+    }
+}
+}
+
+
+int main()
+{
+    hal::init();
+
+    hal::uart_stm32<hal::stm32::uart> uart(USART2);
+    uart.init();
+
+    retarget::set_stdio_uart(&uart);
+
+    ble_fsm my_ble_fsm;
+
+    idle idle_s;
+    advertising advertising_s;
+    connected connected_s;
+
+    my_ble_fsm.add_state(&idle_s);
+    my_ble_fsm.add_state(&advertising_s);
+    my_ble_fsm.add_state(&connected_s);
+
+    const auto print_current_state = [&]() {
+        printf("Current State: %s\n", state_to_string(my_ble_fsm.get_state()));
+    };
+
+    print_current_state();
+
+    my_ble_fsm.handle_event(ble_event::ble_button_pressed);
+    print_current_state();
+
+    my_ble_fsm.handle_event(ble_event::connection_request);
+    print_current_state();
+
+    my_ble_fsm.handle_event(ble_event::ble_button_pressed);
+    print_current_state();
+
+
+    while(true)
+    {
+    }
+}
diff --git a/Chapter17/fsm/libs/boost/sml.hpp b/Chapter17/fsm/libs/boost/sml.hpp
new file mode 100644
index 0000000..ca66764
--- /dev/null
+++ b/Chapter17/fsm/libs/boost/sml.hpp
@@ -0,0 +1,2900 @@
+//
+// Copyright (c) 2016-2024 Kris Jusiak (kris at jusiak dot net)
+//
+// 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)
+//
+#ifndef BOOST_SML_HPP
+#define BOOST_SML_HPP
+#if (__cplusplus < 201305L && _MSC_VER < 1900)
+#error "[Boost::ext].SML requires C++14 support (Clang-3.4+, GCC-5.1+, MSVC-2015+)"
+#else
+#if defined(__ICCARM__) && __IAR_SYSTEMS_ICC__ < 8
+#error "[Boost::ext].SML requires C++14 support (IAR C/C++ ARM 8.1+)"
+#endif
+#define BOOST_SML_VERSION 1'1'11
+#define BOOST_SML_NAMESPACE_BEGIN \
+  namespace boost {               \
+  inline namespace ext {          \
+  namespace sml {                 \
+  inline namespace v1_1_11 {
+#define BOOST_SML_NAMESPACE_END \
+  }                             \
+  }                             \
+  }                             \
+  }
+#if defined(__clang__)
+#define __BOOST_SML_UNUSED __attribute__((unused))
+#define __BOOST_SML_VT_INIT \
+  {}
+#if !defined(BOOST_SML_CFG_DISABLE_MIN_SIZE)
+#define __BOOST_SML_ZERO_SIZE_ARRAY(...) __VA_ARGS__ _[0]
+#else
+#define __BOOST_SML_ZERO_SIZE_ARRAY(...)
+#endif
+#define __BOOST_SML_ZERO_SIZE_ARRAY_CREATE(...)
+#define __BOOST_SML_TEMPLATE_KEYWORD template
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wgnu-string-literal-operator-template"
+#pragma clang diagnostic ignored "-Wzero-length-array"
+#elif defined(__GNUC__)
+#if !defined(__has_builtin)
+#define __BOOST_SML_DEFINED_HAS_BUILTIN
+#define __has_builtin(...) 0
+#endif
+#define __BOOST_SML_UNUSED __attribute__((unused))
+#define __BOOST_SML_VT_INIT \
+  {}
+#if !defined(BOOST_SML_CFG_DISABLE_MIN_SIZE)
+#define __BOOST_SML_ZERO_SIZE_ARRAY(...) __VA_ARGS__ _[0]{}
+#else
+#define __BOOST_SML_ZERO_SIZE_ARRAY(...)
+#endif
+#define __BOOST_SML_ZERO_SIZE_ARRAY_CREATE(...) __VA_ARGS__ ? __VA_ARGS__ : 1
+#define __BOOST_SML_TEMPLATE_KEYWORD template
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+#if defined(__GNUC__) && (__GNUC__ >= 10)
+#pragma GCC diagnostic ignored "-Wsubobject-linkage"
+#endif
+#elif defined(_MSC_VER) && !defined(__clang__)
+#define __BOOST_SML_DEFINED_HAS_BUILTIN
+#define __has_builtin(...) __has_builtin##__VA_ARGS__
+#define __has_builtin__make_integer_seq(...) 1
+#define __BOOST_SML_UNUSED
+#define __BOOST_SML_VT_INIT
+#define __BOOST_SML_ZERO_SIZE_ARRAY(...)
+#define __BOOST_SML_ZERO_SIZE_ARRAY_CREATE(...) __VA_ARGS__ ? __VA_ARGS__ : 1
+#if defined(_MSC_VER) && !defined(__clang__) && _MSC_VER >= 1910  // MSVC 2017
+#define __BOOST_SML_TEMPLATE_KEYWORD template
+#else
+#define __BOOST_SML_TEMPLATE_KEYWORD
+#endif
+#pragma warning(disable : 4503)
+#pragma warning(disable : 4200)
+#elif defined(__ICCARM__)
+#if !defined(__has_builtin)
+#define __BOOST_SML_DEFINED_HAS_BUILTIN
+#define __has_builtin(...) 0
+#endif
+/* Needs IAR language extensions */
+#define __BOOST_SML_UNUSED __attribute__((unused))
+#define __BOOST_SML_VT_INIT \
+  {}
+#define __BOOST_SML_ZERO_SIZE_ARRAY(...)
+#define __BOOST_SML_ZERO_SIZE_ARRAY_CREATE(...) __VA_ARGS__ ? __VA_ARGS__ : 1
+#define __BOOST_SML_TEMPLATE_KEYWORD template
+#endif
+BOOST_SML_NAMESPACE_BEGIN
+#define __BOOST_SML_REQUIRES(...) typename aux::enable_if<__VA_ARGS__, int>::type = 0
+namespace aux {
+using byte = unsigned char;
+struct none_type {};
+template <class...>
+struct type {};
+template <class T, T>
+struct non_type {};
+template <class, class>
+struct pair {};
+template <class...>
+struct type_list {
+  using type = type_list;
+};
+template <bool...>
+struct bool_list {
+  using type = bool_list;
+};
+template <class... Ts>
+struct inherit : Ts... {
+  using type = inherit;
+};
+template <class T>
+struct identity {
+  using type = T;
+};
+template <class T>
+T &&declval();
+template <class T, T V>
+struct integral_constant {
+  using type = integral_constant;
+  static constexpr T value = V;
+};
+using true_type = integral_constant<bool, true>;
+using false_type = integral_constant<bool, false>;
+template <class... Ts>
+using void_t = void;
+template <class...>
+struct always : true_type {};
+template <class...>
+struct never : false_type {};
+namespace detail {
+template <bool>
+struct conditional;
+template <>
+struct conditional<false> {
+  template <class, class T>
+  using fn = T;
+};
+template <>
+struct conditional<true> {
+  template <class T, class>
+  using fn = T;
+};
+}  // namespace detail
+template <bool B, class T, class F>
+struct conditional {
+  using type = typename detail::conditional<B>::template fn<T, F>;
+};
+template <bool B, class T, class F>
+using conditional_t = typename detail::conditional<B>::template fn<T, F>;
+template <bool B, class T = void>
+struct enable_if {};
+template <class T>
+struct enable_if<true, T> {
+  using type = T;
+};
+template <bool B, class T = void>
+using enable_if_t = typename enable_if<B, T>::type;
+template <class, class>
+struct is_same : false_type {};
+template <class T>
+struct is_same<T, T> : true_type {};
+template <class T, class U>
+#if defined(_MSC_VER) && !defined(__clang__)
+struct is_base_of : integral_constant<bool, __is_base_of(T, U)> {
+};
+#else
+using is_base_of = integral_constant<bool, __is_base_of(T, U)>;
+#endif
+template <class T, class... TArgs>
+decltype(T(declval<TArgs>()...), true_type{}) test_is_constructible(int);
+template <class, class...>
+false_type test_is_constructible(...);
+template <class T, class... TArgs>
+#if defined(_MSC_VER) && !defined(__clang__)
+struct is_constructible : decltype(test_is_constructible<T, TArgs...>(0)) {
+};
+#else
+using is_constructible = decltype(test_is_constructible<T, TArgs...>(0));
+#endif
+template <class T, class U>
+struct is_empty_base : T {
+  U _;
+};
+template <class T>
+struct is_empty : aux::integral_constant<bool, sizeof(is_empty_base<T, none_type>) == sizeof(none_type)> {};
+template <class>
+struct function_traits;
+template <class R, class... TArgs>
+struct function_traits<R (*)(TArgs...)> {
+  using args = type_list<TArgs...>;
+};
+template <class R, class... TArgs>
+struct function_traits<R(TArgs...)> {
+  using args = type_list<TArgs...>;
+};
+template <class R, class T, class... TArgs>
+struct function_traits<R (T::*)(TArgs...)> {
+  using args = type_list<TArgs...>;
+};
+template <class R, class T, class... TArgs>
+struct function_traits<R (T::*)(TArgs...) const> {
+  using args = type_list<TArgs...>;
+};
+#if defined(__cpp_noexcept_function_type)
+template <class R, class... TArgs>
+struct function_traits<R (*)(TArgs...) noexcept> {
+  using args = type_list<TArgs...>;
+};
+template <class R, class... TArgs>
+struct function_traits<R(TArgs...) noexcept> {
+  using args = type_list<TArgs...>;
+};
+template <class R, class T, class... TArgs>
+struct function_traits<R (T::*)(TArgs...) noexcept> {
+  using args = type_list<TArgs...>;
+};
+template <class R, class T, class... TArgs>
+struct function_traits<R (T::*)(TArgs...) const noexcept> {
+  using args = type_list<TArgs...>;
+};
+#endif
+template <class T>
+using function_traits_t = typename function_traits<T>::args;
+template <class T>
+struct remove_const {
+  using type = T;
+};
+template <class T>
+struct remove_const<const T> {
+  using type = T;
+};
+template <class T>
+using remove_const_t = typename remove_const<T>::type;
+template <class T>
+struct remove_reference {
+  using type = T;
+};
+template <class T>
+struct remove_reference<T &> {
+  using type = T;
+};
+template <class T>
+struct remove_reference<T &&> {
+  using type = T;
+};
+template <class T>
+using remove_reference_t = typename remove_reference<T>::type;
+template <class T>
+struct remove_pointer {
+  using type = T;
+};
+template <class T>
+struct remove_pointer<T *> {
+  using type = T;
+};
+template <class T>
+using remove_pointer_t = typename remove_pointer<T>::type;
+}  // namespace aux
+namespace aux {
+using swallow = int[];
+template <int...>
+struct index_sequence {
+  using type = index_sequence;
+};
+#if __has_builtin(__make_integer_seq)
+template <class T, T...>
+struct integer_sequence;
+template <int... Ns>
+struct integer_sequence<int, Ns...> {
+  using type = index_sequence<Ns...>;
+};
+template <int N>
+struct make_index_sequence_impl {
+  using type = typename __make_integer_seq<integer_sequence, int, N>::type;
+};
+#else
+template <class, class>
+struct concat;
+template <int... I1, int... I2>
+struct concat<index_sequence<I1...>, index_sequence<I2...>> : index_sequence<I1..., (sizeof...(I1) + I2)...> {};
+template <int N>
+struct make_index_sequence_impl
+    : concat<typename make_index_sequence_impl<N / 2>::type, typename make_index_sequence_impl<N - N / 2>::type>::type {};
+template <>
+struct make_index_sequence_impl<0> : index_sequence<> {};
+template <>
+struct make_index_sequence_impl<1> : index_sequence<0> {};
+#endif
+template <int N>
+using make_index_sequence = typename make_index_sequence_impl<N>::type;
+template <class...>
+struct join {
+  using type = type_list<>;
+};
+template <class T>
+struct join<T> {
+  using type = T;
+};
+template <class... Ts>
+struct join<type_list<Ts...>> : type_list<Ts...> {};
+template <class... T1s, class... T2s>
+struct join<type_list<T1s...>, type_list<T2s...>> : type_list<T1s..., T2s...> {};
+template <class... T1s, class... T2s, class... T3s>
+struct join<type_list<T1s...>, type_list<T2s...>, type_list<T3s...>> : type_list<T1s..., T2s..., T3s...> {};
+template <class... T1s, class... T2s, class... Ts>
+struct join<type_list<T1s...>, type_list<T2s...>, Ts...> : join<type_list<T1s..., T2s...>, Ts...> {};
+template <class... Ts, class... T1s, class... T2s, class... T3s, class... T4s, class... T5s, class... T6s, class... T7s,
+          class... T8s, class... T9s, class... T10s, class... T11s, class... T12s, class... T13s, class... T14s, class... T15s,
+          class... T16s, class... Us>
+struct join<type_list<Ts...>, type_list<T1s...>, type_list<T2s...>, type_list<T3s...>, type_list<T4s...>, type_list<T5s...>,
+            type_list<T6s...>, type_list<T7s...>, type_list<T8s...>, type_list<T9s...>, type_list<T10s...>, type_list<T11s...>,
+            type_list<T12s...>, type_list<T13s...>, type_list<T14s...>, type_list<T15s...>, type_list<T16s...>, Us...>
+    : join<type_list<Ts..., T1s..., T2s..., T3s..., T4s..., T5s..., T6s..., T7s..., T8s..., T9s..., T10s..., T11s..., T12s...,
+                     T13s..., T14s..., T15s..., T16s...>,
+           Us...> {};
+template <class... TArgs>
+using join_t = typename join<TArgs...>::type;
+template <class, class...>
+struct unique_impl;
+template <class T, class... Rs, class... Ts>
+struct unique_impl<type<Rs...>, T, Ts...> : conditional_t<is_base_of<type<T>, inherit<type<Rs>...>>::value,
+                                                          unique_impl<type<Rs...>, Ts...>, unique_impl<type<Rs..., T>, Ts...>> {
+};
+template <class... Rs>
+struct unique_impl<type<Rs...>> : type_list<Rs...> {};
+template <class... Ts>
+struct unique : unique_impl<type<>, Ts...> {};
+template <class T>
+struct unique<T> : type_list<T> {};
+template <class... Ts>
+using unique_t = typename unique<Ts...>::type;
+template <class...>
+struct is_unique;
+template <class T>
+struct is_unique<T> : true_type {};
+template <class T, class... Rs, class... Ts>
+struct is_unique<type<Rs...>, T, Ts...>
+    : conditional_t<is_base_of<type<T>, inherit<type<Rs>...>>::value, false_type, is_unique<type<Rs..., T>, Ts...>> {};
+template <class... Ts>
+using is_unique_t = is_unique<type<>, Ts...>;
+template <template <class...> class, class>
+struct apply;
+template <template <class...> class T, template <class...> class U, class... Ts>
+struct apply<T, U<Ts...>> {
+  using type = T<Ts...>;
+};
+template <template <class...> class T, class D>
+using apply_t = typename apply<T, D>::type;
+template <int, class T>
+struct tuple_type {
+  constexpr explicit tuple_type(const T &object) : value(object) {}
+  T value;
+};
+template <class, class...>
+struct tuple_impl;
+template <int... Ns, class... Ts>
+struct tuple_impl<index_sequence<Ns...>, Ts...> : tuple_type<Ns, Ts>... {
+  constexpr explicit tuple_impl(Ts... ts) : tuple_type<Ns, Ts>(ts)... {}
+};
+template <>
+struct tuple_impl<index_sequence<0>> {
+  __BOOST_SML_ZERO_SIZE_ARRAY(byte);
+};
+template <class... Ts>
+using tuple = tuple_impl<make_index_sequence<sizeof...(Ts)>, Ts...>;
+template <int N, class T>
+constexpr T &get_by_id(tuple_type<N, T> *object) {
+  return static_cast<tuple_type<N, T> &>(*object).value;
+}
+struct init {};
+struct pool_type_base {
+  __BOOST_SML_ZERO_SIZE_ARRAY(byte);
+};
+template <class T, class = void>
+struct pool_type_impl : pool_type_base {
+  constexpr explicit pool_type_impl(T object) : value{object} {}
+  template <class TObject>
+  constexpr pool_type_impl(init i, TObject object) : value{i, object} {}
+  T value{};
+};
+#if defined(BOOST_SML_CREATE_DEFAULT_CONSTRUCTIBLE_DEPS)
+template <class T>
+struct pool_type_impl<T &, aux::enable_if_t<aux::is_constructible<T>::value && aux::is_constructible<T, const T &>::value>>
+    : pool_type_base {
+  constexpr explicit pool_type_impl(T &value) : value{value} {}
+  template <class TObject>
+  constexpr explicit pool_type_impl(TObject value) : value_{value}, value{value_} {}
+  template <class TObject>
+  constexpr pool_type_impl(const init &i, const TObject &object) : value(i, object) {}
+  T value_{};
+  T &value;
+};
+#endif
+template <class T>
+struct pool_type : pool_type_impl<T> {
+  using pool_type_impl<T>::pool_type_impl;
+};
+template <class T>
+struct missing_ctor_parameter {
+  static constexpr auto value = false;
+  constexpr auto operator()() const { return T{}(); }
+  template <class U, __BOOST_SML_REQUIRES(!aux::is_base_of<pool_type_base, U>::value && aux::is_constructible<U>::value)>
+  constexpr operator U() {
+    return {};
+  }
+#if !(defined(_MSC_VER) && !defined(__clang__))
+  template <class TMissing, __BOOST_SML_REQUIRES(!aux::is_base_of<pool_type_base, TMissing>::value)>
+  constexpr operator TMissing &() const {
+    static_assert(missing_ctor_parameter<TMissing>::value,
+                  "State Machine is missing a constructor parameter! Check out the `missing_ctor_parameter` error to see the "
+                  "missing type.");
+  }
+#endif
+};
+template <class T>
+constexpr missing_ctor_parameter<T> try_get(...) {
+  return {};
+}
+template <class T>
+constexpr T try_get(const pool_type<T> *object) {
+  return object->value;
+}
+template <class T>
+constexpr const T &try_get(const pool_type<const T &> *object) {
+  return object->value;
+}
+template <class T>
+constexpr T &try_get(const pool_type<T &> *object) {
+  return object->value;
+}
+template <class T>
+constexpr const T *try_get(const pool_type<const T *> *object) {
+  return object->value;
+}
+template <class T>
+constexpr T *try_get(const pool_type<T *> *object) {
+  return object->value;
+}
+template <class T, class TPool>
+constexpr bool would_instantiate_missing_ctor_parameter() {
+  return is_same<missing_ctor_parameter<T>, decltype(try_get<T>(aux::declval<TPool>()))>::value;
+}
+template <class T, class TPool>
+constexpr T &get(TPool &p) {
+  return static_cast<pool_type<T> &>(p).value;
+}
+template <class T, class TPool>
+constexpr const T &cget(const TPool &p) {
+  return static_cast<const pool_type<T> &>(p).value;
+}
+template <class T, class TPool>
+T *get(TPool *p) {
+  return static_cast<pool_type<T> &>(p).value;
+}
+template <class T, class TPool>
+const T *cget(const TPool *p) {
+  return static_cast<const pool_type<T> &>(p).value;
+}
+template <class... Ts>
+struct pool : pool_type<Ts>... {
+  using boost_di_inject__ = type_list<Ts...>;
+  constexpr pool() = default;
+  constexpr explicit pool(Ts... ts) : pool_type<Ts>(ts)... {}
+  template <class... TArgs>
+  constexpr pool(init, const pool<TArgs...> &p)
+      : pool_type<Ts>(try_get<aux::remove_const_t<aux::remove_reference_t<aux::remove_pointer_t<Ts>>>>(&p))... {}
+  template <class... TArgs>
+  constexpr pool(const pool<TArgs...> &p) : pool_type<Ts>(init{}, p)... {}
+};
+template <>
+struct pool<> {
+  using boost_di_inject__ = type_list<>;
+  pool() = default;
+  template <class... Ts>
+  constexpr explicit pool(Ts &&...) {}
+  __BOOST_SML_ZERO_SIZE_ARRAY(byte);
+};
+template <int, class>
+struct type_id_type {};
+template <class, class...>
+struct type_id_impl;
+template <int... Ns, class... Ts>
+struct type_id_impl<index_sequence<Ns...>, Ts...> : type_id_type<Ns, Ts>... {};
+template <class... Ts>
+struct type_id : type_id_impl<make_index_sequence<sizeof...(Ts)>, Ts...> {};
+template <class R, class T, int N>
+constexpr R get_id(type_id_type<N, T> *) {
+  return static_cast<R>(N);
+}
+template <template <class...> class, class T>
+struct is : false_type {};
+template <template <class...> class T, class... Ts>
+struct is<T, T<Ts...>> : true_type {};
+template <class>
+struct size;
+template <template <class...> class T, class... Ts>
+struct size<T<Ts...>> {
+  static constexpr auto value = sizeof...(Ts);
+};
+template <int... Ts>
+constexpr int max_element() {
+  int max = 0;
+  (void)swallow{0, (Ts > max ? max = Ts : max)...};
+  return max;
+}
+template <class TExpr, class = void>
+struct zero_wrapper : TExpr {
+  using type = TExpr;
+  constexpr explicit zero_wrapper(const TExpr &expr) : TExpr(expr) {}
+  constexpr const TExpr &get() const { return *this; }
+};
+template <class R, class TBase, class... TArgs, class T>
+struct zero_wrapper<R (TBase::*)(TArgs...), T> {
+  using type = R (TBase::*)(TArgs...);
+  constexpr explicit zero_wrapper(type ptr) : ptr{ptr} {}
+  constexpr auto operator()(TBase &self, TArgs... args) { return (self.*ptr)(args...); }
+  constexpr type get() const { return ptr; }
+
+ private:
+  type ptr{};
+};
+template <class R, class TBase, class... TArgs, class T>
+struct zero_wrapper<R (TBase::*)(TArgs...) const, T> {
+  using type = R (TBase::*)(TArgs...) const;
+  constexpr explicit zero_wrapper(type ptr) : ptr{ptr} {}
+  constexpr auto operator()(TBase &self, TArgs... args) { return (self.*ptr)(args...); }
+  constexpr type get() const { return ptr; }
+
+ private:
+  type ptr{};
+};
+template <class R, class... TArgs, class T>
+struct zero_wrapper<R (*)(TArgs...), T> {
+  using type = R (*)(TArgs...);
+  explicit zero_wrapper(type ptr) : ptr{ptr} {}
+  constexpr auto operator()(TArgs... args) { return (*ptr)(args...); }
+  constexpr type get() const { return ptr; }
+
+ private:
+  type ptr{};
+};
+#if defined(__cpp_noexcept_function_type)
+template <class R, class TBase, class... TArgs, class T>
+struct zero_wrapper<R (TBase::*)(TArgs...) noexcept, T> {
+  using type = R (TBase::*)(TArgs...) noexcept;
+  constexpr explicit zero_wrapper(type ptr) : ptr{ptr} {}
+  constexpr auto operator()(TBase &self, TArgs... args) { return (self.*ptr)(args...); }
+  constexpr type get() const { return ptr; }
+
+ private:
+  type ptr {};
+};
+template <class R, class TBase, class... TArgs, class T>
+struct zero_wrapper<R (TBase::*)(TArgs...) const noexcept, T> {
+  using type = R (TBase::*)(TArgs...) const noexcept;
+  constexpr explicit zero_wrapper(type ptr) : ptr{ptr} {}
+  constexpr auto operator()(TBase &self, TArgs... args) { return (self.*ptr)(args...); }
+  constexpr type get() const { return ptr; }
+
+ private:
+  type ptr {};
+};
+template <class R, class... TArgs, class T>
+struct zero_wrapper<R (*)(TArgs...) noexcept, T> {
+  using type = R (*)(TArgs...) noexcept;
+  explicit zero_wrapper(type ptr) : ptr{ptr} {}
+  constexpr auto operator()(TArgs... args) { return (*ptr)(args...); }
+  constexpr type get() const { return ptr; }
+
+ private:
+  type ptr {};
+};
+#endif
+template <class, class>
+struct zero_wrapper_impl;
+template <class TExpr, class... TArgs>
+struct zero_wrapper_impl<TExpr, type_list<TArgs...>> {
+  constexpr auto operator()(TArgs... args) const { return reinterpret_cast<const TExpr &>(*this)(args...); }
+  __BOOST_SML_ZERO_SIZE_ARRAY(byte);
+};
+template <class TExpr>
+struct zero_wrapper<TExpr, void_t<decltype(+declval<TExpr>())>>
+    : zero_wrapper_impl<TExpr, function_traits_t<decltype(&TExpr::operator())>> {
+  using type = TExpr;
+  template <class... Ts>
+  constexpr zero_wrapper(Ts &&...) {}
+  const TExpr &get() const { return reinterpret_cast<const TExpr &>(*this); }
+};
+namespace detail {
+template <class, int N, int... Ns>
+auto get_type_name(const char *ptr, index_sequence<Ns...>) {
+  static const char str[] = {ptr[N + Ns]..., 0};
+  return str;
+}
+}  // namespace detail
+template <class T>
+const char *get_type_name() {
+#if defined(_MSC_VER) && !defined(__clang__)
+  return detail::get_type_name<T, 65>(__FUNCSIG__, make_index_sequence<sizeof(__FUNCSIG__) - 65 - 8>{});
+#elif defined(__clang__) && (__clang_major__ >= 12)
+  return detail::get_type_name<T, 50>(__PRETTY_FUNCTION__, make_index_sequence<sizeof(__PRETTY_FUNCTION__) - 50 - 2>{});
+#elif defined(__clang__)
+  return detail::get_type_name<T, 63>(__PRETTY_FUNCTION__, make_index_sequence<sizeof(__PRETTY_FUNCTION__) - 63 - 2>{});
+#elif defined(__GNUC__)
+  return detail::get_type_name<T, 69>(__PRETTY_FUNCTION__, make_index_sequence<sizeof(__PRETTY_FUNCTION__) - 69 - 2>{});
+#elif defined(__ICCARM__)
+  return detail::get_type_name<T, 72>(__PRETTY_FUNCTION__, make_index_sequence<sizeof(__PRETTY_FUNCTION__) - 72 -2>{});
+#endif
+}
+#if defined(__cpp_nontype_template_parameter_class) || \
+    defined(__cpp_nontype_template_args) && __cpp_nontype_template_args >= 201911L
+template <auto N>
+struct fixed_string {
+  static constexpr auto size = N;
+  char data[N + 1]{};
+  constexpr fixed_string(char const *str) {
+    for (decltype(N) i = 0; i < N; ++i) {
+      data[i] = str[i];
+    }
+  }
+};
+template <auto N>
+fixed_string(char const (&)[N]) -> fixed_string<N - 1>;
+#endif
+template <class T, T...>
+struct string;
+template <char... Chrs>
+struct string<char, Chrs...> {
+  using type = string;
+  static auto c_str() {
+    static constexpr char str[] = {Chrs..., 0};
+    return str;
+  }
+};
+template <class T>
+struct string<T> {
+  using type = T;
+  constexpr static auto c_str() { return c_str_impl((T *)0); }
+  template <class U>
+  constexpr static decltype(U::c_str()) c_str_impl(U *) {
+    return U::c_str();
+  }
+  constexpr static auto c_str_impl(...) { return get_type_name<T>(); }
+};
+}  // namespace aux
+template <class T>
+constexpr auto wrap(T callback) {
+  return aux::zero_wrapper<T, T>{callback};
+}
+namespace back {
+namespace policies {
+struct defer_queue_policy__ {};
+template <template <class...> class T>
+struct defer_queue : aux::pair<back::policies::defer_queue_policy__, defer_queue<T>> {
+  template <class U>
+  using rebind = T<U>;
+  using flag = bool;
+};
+}  // namespace policies
+}  // namespace back
+namespace back {
+template <class... Ts>
+class queue_event {
+  using ids_t = aux::type_id<Ts...>;
+  static constexpr auto alignment = aux::max_element<alignof(Ts)...>();
+  static constexpr auto size = aux::max_element<sizeof(Ts)...>();
+  template <class T>
+  constexpr static void dtor_impl(aux::byte *data) {
+    (void)data;
+    reinterpret_cast<T *>(data)->~T();
+  }
+  template <class T>
+  constexpr static void move_impl(aux::byte (&data)[size], queue_event &&other) {
+    new (&data) T(static_cast<T &&>(*reinterpret_cast<T *>(other.data)));
+  }
+
+ public:
+  constexpr queue_event() : dtor(nullptr) {}
+  constexpr queue_event(queue_event &&other) : id(other.id), dtor(other.dtor), move(other.move) {
+    move(data, static_cast<queue_event &&>(other));
+  }
+  constexpr queue_event &operator=(queue_event &&other) {
+    if (dtor != nullptr) {
+      dtor(data);
+    }
+    id = other.id;
+    dtor = other.dtor;
+    move = other.move;
+    move(data, static_cast<queue_event &&>(other));
+    return *this;
+  }
+  constexpr queue_event(const queue_event &) = delete;
+  constexpr queue_event &operator=(const queue_event &) = delete;
+  template <class T>
+  constexpr queue_event(T object) {
+    id = aux::get_id<int, T>((ids_t *)0);
+    dtor = &dtor_impl<T>;
+    move = &move_impl<T>;
+    new (&data) T(static_cast<T &&>(object));
+  }
+  ~queue_event() {
+    if (dtor) {
+      dtor(data);
+    }
+  }
+  alignas(alignment) aux::byte data[size];
+  int id = -1;
+
+ private:
+  void (*dtor)(aux::byte *);
+  void (*move)(aux::byte (&)[size], queue_event &&);
+};
+template <class TEvent>
+class queue_event_call {
+  using call_t = void (*)(void *, const TEvent &);
+
+ public:
+  constexpr queue_event_call() = default;
+  constexpr explicit queue_event_call(const call_t &call) : call{call} {}
+  call_t call{};
+};
+template <class... TEvents>
+struct queue_handler : queue_event_call<TEvents>... {
+  constexpr queue_handler() = default;
+  template <class TQueue, class = typename TQueue::container_type>
+  constexpr explicit queue_handler(TQueue &queue)
+      : queue_event_call<TEvents>(queue_handler::push_impl<TQueue, TEvents>)..., queue_{&queue} {}
+  template <class TEvent>
+  constexpr void operator()(const TEvent &event) {
+    static_cast<queue_event_call<TEvent> *>(this)->call(queue_, event);
+  }
+
+ private:
+  template <class TQueue, class TEvent>
+  constexpr static auto push_impl(void *queue, const TEvent &event) {
+    static_cast<TQueue *>(queue)->push(event);
+  }
+  void *queue_{};
+};
+template <class... TEvents>
+struct deque_handler : queue_event_call<TEvents>... {
+  constexpr deque_handler() = default;
+  template <class TDeque, class = typename TDeque::allocator_type>
+  constexpr explicit deque_handler(TDeque &deque)
+      : queue_event_call<TEvents>(deque_handler::push_impl<TDeque, TEvents>)..., deque_{&deque} {}
+  template <class TEvent>
+  constexpr void operator()(const TEvent &event) {
+    static_cast<queue_event_call<TEvent> *>(this)->call(deque_, event);
+  }
+
+ private:
+  template <class TDeque, class TEvent>
+  constexpr static auto push_impl(void *deque, const TEvent &event) {
+    static_cast<TDeque *>(deque)->push_back(event);
+  }
+  void *deque_{};
+};
+}  // namespace back
+namespace back {
+struct _ {};
+struct initial {};
+struct unexpected {};
+struct entry_exit {};
+struct terminate_state {
+  constexpr static auto c_str() { return "terminate"; }
+};
+struct internal_event {
+  constexpr static auto c_str() { return "internal_event"; }
+};
+struct anonymous : internal_event {
+  constexpr static auto c_str() { return "anonymous"; }
+};
+template <class T, class TEvent = T>
+struct on_entry : internal_event, entry_exit {
+  constexpr static auto c_str() { return "on_entry"; }
+  constexpr explicit on_entry(const TEvent &event = {}) : event_(event) {}
+  const TEvent &event_;
+};
+template <class T, class TEvent = T>
+struct on_exit : internal_event, entry_exit {
+  constexpr static auto c_str() { return "on_exit"; }
+  constexpr explicit on_exit(const TEvent &event = {}) : event_(event) {}
+  const TEvent &event_;
+};
+template <class T, class TException = T>
+struct exception : internal_event {
+  using type = TException;
+  constexpr explicit exception(const TException &exception = {}) : exception_(exception) {}
+  const TException &exception_;
+};
+template <class T, class TEvent = T>
+struct unexpected_event : internal_event, unexpected {
+  constexpr explicit unexpected_event(const TEvent &event = {}) : event_(event) {}
+  const TEvent &event_;
+};
+template <class TEvent>
+struct event_type {
+  using event_t = TEvent;
+  using generic_t = TEvent;
+  using mapped_t = void;
+};
+template <class TEvent>
+struct event_type<exception<TEvent>> {
+  using event_t = TEvent;
+  using generic_t = exception<TEvent>;
+  using mapped_t = void;
+};
+template <class TEvent, class T>
+struct event_type<unexpected_event<T, TEvent>> {
+  using event_t = TEvent;
+  using generic_t = unexpected_event<T>;
+  using mapped_t = void;
+};
+template <class TEvent, class T>
+struct event_type<on_entry<T, TEvent>> {
+  using event_t = TEvent;
+  using generic_t = on_entry<T>;
+  using mapped_t = on_entry<T, TEvent>;
+};
+template <class TEvent, class T>
+struct event_type<on_exit<T, TEvent>> {
+  using event_t = TEvent;
+  using generic_t = on_exit<T>;
+  using mapped_t = on_exit<T, TEvent>;
+};
+template <class TEvent>
+using get_event_t = typename event_type<TEvent>::event_t;
+template <class TEvent>
+using get_generic_t = typename event_type<TEvent>::generic_t;
+template <class TEvent>
+using get_mapped_t = typename event_type<TEvent>::mapped_t;
+template <class... TEvents>
+struct process : queue_handler<TEvents...> {
+  using queue_handler<TEvents...>::queue_handler;
+};
+template <class... TEvents>
+struct defer : deque_handler<TEvents...> {
+  using deque_handler<TEvents...>::deque_handler;
+};
+}  // namespace back
+namespace back {
+template <class>
+class sm;
+template <class>
+struct sm_impl;
+template <class, class...>
+struct sm_policy;
+template <class TEvent>
+using get_event = aux::conditional_t<aux::is_base_of<internal_event, TEvent>::value, aux::type_list<>, aux::type_list<TEvent>>;
+template <class, class, class TEvent>
+struct get_all_events_impl {
+  using type = get_event<TEvent>;
+};
+template <class TSrc, class TDst, class TEvent>
+struct get_all_events_impl<TSrc, TDst, unexpected_event<TEvent>> {
+  using type = aux::type_list<TEvent>;
+};
+template <class TSrc, class TDst, class TEvent>
+struct get_all_events_impl<sm<TSrc>, TDst, TEvent> {
+  using type = aux::join_t<get_event<TEvent>, typename sm<TSrc>::events>;
+};
+template <class TSrc, class TDst, class TEvent>
+struct get_all_events_impl<TSrc, sm<TDst>, TEvent> {
+  using type = aux::join_t<get_event<TEvent>, typename sm<TDst>::events>;
+};
+template <class TSrc, class TDst, class TEvent>
+struct get_all_events_impl<sm<TSrc>, sm<TDst>, TEvent> {
+  using type = aux::join_t<get_event<TEvent>, typename sm<TSrc>::events, typename sm<TDst>::events>;
+};
+template <class, class TEvent>
+struct get_sub_internal_events_impl {
+  using type = aux::conditional_t<aux::is_base_of<internal_event, TEvent>::value, aux::type_list<TEvent>, aux::type_list<>>;
+};
+template <class T, class TEvent>
+struct get_sub_internal_events_impl<sm<T>, TEvent> {
+  using type = aux::join_t<aux::type_list<TEvent>, typename sm_impl<T>::sub_internal_events_t>;
+};
+template <class... Ts>
+using get_all_events =
+    aux::join_t<typename get_all_events_impl<typename Ts::src_state, typename Ts::dst_state, typename Ts::event>::type...>;
+template <class... Ts>
+using get_sub_internal_events =
+    aux::join_t<typename get_sub_internal_events_impl<typename Ts::src_state, typename Ts::event>::type...,
+                typename get_sub_internal_events_impl<typename Ts::dst_state, typename Ts::event>::type...>;
+template <class... Ts>
+using get_events = aux::type_list<typename Ts::event...>;
+template <class T>
+struct get_exception : aux::type_list<> {};
+template <class T>
+struct get_exception<exception<T>> : aux::type_list<exception<T>> {};
+template <class... Ts>
+using get_exceptions = aux::join_t<typename get_exception<Ts>::type...>;
+template <class... Ts>
+using get_states = aux::join_t<aux::type_list<typename Ts::src_state, typename Ts::dst_state>...>;
+template <class... Ts>
+using get_initial_states =
+    aux::join_t<typename aux::conditional<Ts::initial, aux::type_list<typename Ts::src_state>, aux::type_list<>>::type...>;
+template <class... Ts>
+using get_history_states = aux::join_t<
+    typename aux::conditional<!Ts::history && Ts::initial, aux::type_list<typename Ts::src_state>, aux::type_list<>>::type...>;
+template <class>
+struct get_sub_sm : aux::type_list<> {};
+template <class T>
+struct get_sub_sm<sm<T>> : aux::join_t<aux::type_list<T>, typename sm<T>::state_machines> {};
+template <class... Ts>
+using get_sub_sms = aux::join_t<typename get_sub_sm<Ts>::type...>;
+template <class... Ts>
+using get_sm_t = aux::type_list<typename Ts::sm...>;
+template <class... Ts>
+using get_non_empty_t =
+    aux::join_t<typename aux::conditional<aux::is_empty<Ts>::value, aux::type_list<>, aux::type_list<Ts>>::type...>;
+template <class... Ts>
+using merge_deps = aux::join_t<typename Ts::deps...>;
+template <class>
+struct sub_sm;
+template <class T>
+struct sub_sm<sm_impl<sm_policy<T>>> {
+  template <class U, class... TPolicies>
+  constexpr static sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>> &get(
+      aux::pool_type<sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>>> *object) {
+    return static_cast<aux::pool_type<sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>>> &>(*object).value;
+  }
+  template <class... TPolicies>
+  constexpr static sm_impl<sm_policy<T, TPolicies...>> &get(aux::pool_type<sm_impl<sm_policy<T, TPolicies...>>> *object) {
+    return static_cast<aux::pool_type<sm_impl<sm_policy<T, TPolicies...>>> &>(*object).value;
+  }
+  template <class... TPolicies>
+  constexpr static const sm_impl<sm_policy<T, TPolicies...>> &cget(const aux::pool_type<sm_impl<sm_policy<T, TPolicies...>>> *object) {
+    return static_cast<const aux::pool_type<sm_impl<sm_policy<T, TPolicies...>>> &>(*object).value;
+  }
+};
+template <class T, class U>
+struct sub_sm<sm_impl<sm_policy<T, aux::identity<U>>>> {
+  template <class... TPolicies>
+  constexpr static sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>> &get(
+      aux::pool_type<sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>>> *object) {
+    return static_cast<aux::pool_type<sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>>> &>(*object).value;
+  }
+  template <class... TPolicies>
+  constexpr static const sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>> &cget(
+      const aux::pool_type<sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>>> *object) {
+    return static_cast<const aux::pool_type<sm_impl<sm_policy<T, aux::identity<U>, TPolicies...>>> &>(*object).value;
+  }
+};
+template <class T, class... TPolicies>
+struct rebind_impl {
+  using type = sm_policy<T, TPolicies...>;
+};
+template <class T, class... TDetails, class... TPolicies>
+struct rebind_impl<sm_policy<T, TDetails...>, TPolicies...> {
+  using type = sm_policy<T, TDetails..., TPolicies...>;
+};
+template <class T, class... TDetails, class... TPolicies>
+struct rebind_impl<sm<sm_policy<T, TDetails...>>, TPolicies...> {
+  using type = sm_policy<T, TDetails..., TPolicies...>;
+};
+template <class, class>
+struct convert_to_sm;
+template <class T, class... Ts>
+struct convert_to_sm<T, aux::type_list<Ts...>> {
+  using type = aux::type_list<sm_impl<T>, sm_impl<typename T::template rebind<Ts>>...>;
+};
+}  // namespace back
+namespace back {
+template <class>
+class sm;
+template <class>
+struct sm_impl;
+template <class...>
+struct transitions;
+template <class...>
+struct transitions_sub;
+template <class T, class... Ts>
+struct transitions<T, Ts...> {
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state) {
+    if (aux::get<T>(sm.transitions_).execute(event, sm, deps, subs, current_state, typename SM::has_entry_exits{})) {
+      return true;
+    }
+    return transitions<Ts...>::execute(event, sm, deps, subs, current_state);
+  }
+};
+template <class T>
+struct transitions<T> {
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state) {
+    return aux::get<T>(sm.transitions_).execute(event, sm, deps, subs, current_state, typename SM::has_entry_exits{});
+  }
+};
+template <>
+struct transitions<aux::true_type> {
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  static bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state) {
+    sm.process_internal_event(unexpected_event<TEvent>{event}, deps, subs, current_state);
+    return false;
+  }
+};
+template <>
+struct transitions<aux::false_type> {
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute(const TEvent &, SM &, TDeps &, TSubs &, typename SM::state_t &) {
+    return false;
+  }
+};
+template <class Tsm, class T, class... Ts>
+struct transitions_sub<sm<Tsm>, T, Ts...> {
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state) {
+    return execute_impl(event, sm, deps, subs, current_state);
+  }
+  template <class, class SM, class TDeps, class TSubs>
+  constexpr static bool execute(const anonymous &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state) {
+    if (sub_sm<sm_impl<Tsm>>::cget(&subs).is_terminated()) {
+      const auto handled = sub_sm<sm_impl<Tsm>>::get(&subs).process_event(event, deps, subs);
+      return handled ? handled : transitions<T, Ts...>::execute(event, sm, deps, subs, current_state);
+    }
+    return false;
+  }
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute_impl(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state) {
+    const auto handled = sub_sm<sm_impl<Tsm>>::get(&subs).process_event(event, deps, subs);
+    return handled ? handled : transitions<T, Ts...>::execute(event, sm, deps, subs, current_state);
+  }
+  template <class _, class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute_impl(const back::on_entry<_, TEvent> &event, SM &sm, TDeps &deps, TSubs &subs,
+                           typename SM::state_t &current_state) {
+    transitions<T, Ts...>::execute(event, sm, deps, subs, current_state);
+    sub_sm<sm_impl<Tsm>>::get(&subs).process_event(event, deps, subs);
+    return true;
+  }
+  template <class _, class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute_impl(const back::on_exit<_, TEvent> &event, SM &sm, TDeps &deps, TSubs &subs,
+                           typename SM::state_t &current_state) {
+    sub_sm<sm_impl<Tsm>>::get(&subs).process_event(event, deps, subs);
+    transitions<T, Ts...>::execute(event, sm, deps, subs, current_state);
+    return true;
+  }
+};
+template <class Tsm>
+struct transitions_sub<sm<Tsm>> {
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr static bool execute(const TEvent &event, SM &, TDeps &deps, TSubs &subs, typename SM::state_t &) {
+    return sub_sm<sm_impl<Tsm>>::get(&subs).process_event(event, deps, subs);
+  }
+  template <class, class SM, class TDeps, class TSubs>
+  constexpr static bool execute(const anonymous &, SM &, TDeps &, TSubs &, typename SM::state_t &) {
+    return false;
+  }
+};
+}  // namespace back
+namespace back {
+template <class>
+class sm;
+template <class>
+struct state;
+template <class>
+struct event;
+template <class...>
+struct transitions;
+template <class...>
+struct transitions_sub;
+template <class, class>
+struct state_mappings;
+template <class S, class... Ts>
+struct state_mappings<S, aux::type_list<Ts...>> {
+  using element_type = state<S>;
+  using types = aux::type_list<Ts...>;
+};
+template <class, class>
+struct event_mappings;
+template <class E, class... Ts>
+struct event_mappings<E, aux::inherit<Ts...>> {
+  using element_type = event<E>;
+  using types = aux::type_list<Ts...>;
+};
+template <class...>
+struct unique_mappings;
+template <class, class...>
+struct unique_mappings_impl;
+template <class... Ts>
+using unique_mappings_t = typename unique_mappings<Ts...>::type;
+template <class, class, class, class R>
+struct get_mapping : aux::type_list<R> {};
+template <class E, class T, class R>
+struct get_mapping<event<E>, event<E>, T, R>
+    : aux::type_list<event_mappings<E, aux::apply_t<unique_mappings_t, aux::join_t<typename R::types, typename T::types>>>> {};
+template <class S, class T, class R>
+struct get_mapping<state<S>, state<S>, T, R>
+    : aux::type_list<state_mappings<S, aux::join_t<typename R::types, typename T::types>>> {};
+template <class T, class... Ts>
+struct extend_mapping : aux::join_t<typename get_mapping<typename T::element_type, typename Ts::element_type, T, Ts>::type...> {
+};
+template <class T, class... Ts>
+using extend_mapping_t = aux::apply_t<aux::inherit, typename extend_mapping<T, Ts...>::type>;
+template <bool, class, class...>
+struct conditional_mapping;
+template <class T1, class T2, class... Rs, class... Ts>
+struct conditional_mapping<true, aux::type<T1, aux::inherit<Rs...>>, T2, Ts...> {
+  using type = unique_mappings_impl<aux::type<aux::inherit<T1>, extend_mapping_t<T2, Rs...>>, Ts...>;
+};
+template <class T1, class T2, class... Rs, class... Ts>
+struct conditional_mapping<false, aux::type<T1, aux::inherit<Rs...>>, T2, Ts...> {
+  using type =
+      unique_mappings_impl<aux::type<aux::inherit<T1, aux::type<typename T2::element_type>>, aux::inherit<T2, Rs...>>, Ts...>;
+};
+template <class T1, class T2, class... Rs, class... Ts>
+struct unique_mappings_impl<aux::type<T1, aux::inherit<Rs...>>, T2, Ts...>
+    : conditional_mapping<aux::is_base_of<aux::type<typename T2::element_type>, T1>::value, aux::type<T1, aux::inherit<Rs...>>,
+                          T2, Ts...>::type {};
+template <class T1, class Rs>
+struct unique_mappings_impl<aux::type<T1, Rs>> : aux::apply_t<aux::inherit, Rs> {};
+template <class... Ts>
+struct unique_mappings : unique_mappings_impl<aux::type<aux::none_type, aux::inherit<>>, Ts...> {};
+template <class T>
+struct unique_mappings<T> : aux::inherit<T> {};
+template <class, class...>
+struct mappings;
+template <class... Ts>
+struct mappings<aux::pool<Ts...>>
+    : unique_mappings_t<
+          event_mappings<typename Ts::event, aux::inherit<state_mappings<typename Ts::src_state, aux::type_list<Ts>>>>...> {};
+template <class T>
+using mappings_t = typename mappings<T>::type;
+template <class, class TUnexpected>
+transitions<TUnexpected> get_state_mapping_impl(...);
+template <class T, class, class... Ts>
+transitions<Ts...> get_state_mapping_impl(state_mappings<T, aux::type_list<Ts...>> *);
+template <class T, class TMappings, class TUnexpected>
+struct get_state_mapping {
+  using type = aux::conditional_t<aux::is_same<decltype(get_state_mapping_impl<T, TUnexpected>((TMappings *)0)), transitions<TUnexpected>>::value,
+      decltype(get_state_mapping_impl<_, TUnexpected>((TMappings *)0)),
+      decltype(get_state_mapping_impl<T, TUnexpected>((TMappings *)0))>;
+};
+template <class S>
+transitions_sub<S> get_sub_state_mapping_impl(...);
+template <class T, class... Ts>
+transitions_sub<T, Ts...> get_sub_state_mapping_impl(state_mappings<T, aux::type_list<Ts...>> *);
+template <class T, class TMappings, class TUnexpected>
+struct get_state_mapping<sm<T>, TMappings, TUnexpected> {
+  using type = decltype(get_sub_state_mapping_impl<sm<T>>((TMappings *)0));
+};
+template <class T, class TMappings, class TUnexpected>
+using get_state_mapping_t = typename get_state_mapping<T, TMappings, TUnexpected>::type;
+template <class>
+transitions<aux::true_type> get_event_mapping_impl(...);
+template <class T, class TMappings>
+TMappings get_event_mapping_impl(event_mappings<T, TMappings> *);
+template <class T, class... T1Mappings, class... T2Mappings>
+unique_mappings_t<T1Mappings..., T2Mappings...> get_event_mapping_impl(event_mappings<T, aux::inherit<T1Mappings...>> *,
+                                                                       event_mappings<_, aux::inherit<T2Mappings...>> *);
+template <class T, class TMappings>
+struct get_event_mapping_impl_helper
+    : aux::conditional<aux::is_same<transitions<aux::true_type>, decltype(get_event_mapping_impl<_>((TMappings *)0))>::value,
+                       decltype(get_event_mapping_impl<T>((TMappings *)0)),
+                       decltype(get_event_mapping_impl<T>((TMappings *)0, (TMappings *)0))>::type {};
+template <class T, class TMappings>
+struct get_event_mapping_impl_helper<exception<T>, TMappings> : decltype(get_event_mapping_impl<exception<T>>((TMappings *)0)) {
+};
+template <class T1, class T2, class TMappings>
+struct get_event_mapping_impl_helper<unexpected_event<T1, T2>, TMappings>
+    : decltype(get_event_mapping_impl<unexpected_event<T1, T2>>((TMappings *)0)) {};
+template <class T1, class T2, class TMappings>
+struct get_event_mapping_impl_helper<on_entry<T1, T2>, TMappings>
+    : decltype(get_event_mapping_impl<on_entry<T1, T2>>((TMappings *)0)) {};
+template <class T1, class T2, class TMappings>
+struct get_event_mapping_impl_helper<on_exit<T1, T2>, TMappings>
+    : decltype(get_event_mapping_impl<on_exit<T1, T2>>((TMappings *)0)) {};
+template <class T, class TMappings>
+using get_event_mapping_t = get_event_mapping_impl_helper<T, TMappings>;
+}  // namespace back
+namespace back {
+namespace policies {
+struct dispatch_policy__ {};
+template <class T>
+struct dispatch : aux::pair<dispatch_policy__, T> {
+  using type = T;
+};
+struct jump_table {
+  template <int, class TMappings, class sm_impl, class State, class TEvent, class TDeps, class TSubs>
+  constexpr static bool dispatch(sm_impl &, State &, const TEvent &, TDeps &, TSubs &, const aux::type_list<> &) {
+    return false;
+  }
+  template <int, class TMappings, class sm_impl, class State, class TEvent, class TDeps, class TSubs, class... TStates>
+  static bool dispatch(sm_impl &self, State &current_state, const TEvent &event, TDeps &deps, TSubs &subs,
+                       const aux::type_list<TStates...> &) {
+    using dispatch_table_t = bool (*)(const TEvent &, sm_impl &, TDeps &, TSubs &, State &);
+    constexpr static dispatch_table_t dispatch_table[__BOOST_SML_ZERO_SIZE_ARRAY_CREATE(sizeof...(TStates))] = {
+        &get_state_mapping_t<TStates, TMappings, typename sm_impl::has_unexpected_events>::template execute<TEvent, sm_impl,
+                                                                                                            TDeps, TSubs>...};
+    return dispatch_table[current_state](event, self, deps, subs, current_state);
+  }
+};
+struct branch_stm {
+  template <int, class TMappings, class sm_impl, class State, class TEvent, class TDeps, class TSubs>
+  constexpr static bool dispatch(sm_impl &, State &, const TEvent &, TDeps &, TSubs &, const aux::type_list<> &) {
+    return false;
+  }
+  template <int N, class TMappings, class sm_impl, class State, class TEvent, class TDeps, class TSubs, class TState,
+            class... TStates>
+  constexpr static bool dispatch(sm_impl &self, State &current_state, const TEvent &event, TDeps &deps, TSubs &subs,
+                       const aux::type_list<TState, TStates...> &) {
+    return current_state == N
+               ? get_state_mapping_t<TState, TMappings, typename sm_impl::has_unexpected_events>::template execute<
+                     TEvent, sm_impl, TDeps, TSubs>(event, self, deps, subs, current_state)
+               : dispatch<N + 1, TMappings>(self, current_state, event, deps, subs, aux::type_list<TStates...>{});
+  }
+};
+struct switch_stm {
+  template <int, class TMappings, class sm_impl, class State, class TEvent, class TDeps, class TSubs>
+  constexpr static bool dispatch(sm_impl &, State &, const TEvent &, TDeps &, TSubs &, const aux::type_list<> &) {
+    return false;
+  }
+  template <int N, class TMappings, class sm_impl, class State, class TEvent, class TDeps, class TSubs, class TState,
+            class... TStates>
+  constexpr static bool dispatch(sm_impl &self, State &current_state, const TEvent &event, TDeps &deps, TSubs &subs,
+                       const aux::type_list<TState, TStates...> &) {
+    switch (current_state) {
+      case N:
+        return get_state_mapping_t<TState, TMappings, typename sm_impl::has_unexpected_events>::template execute<
+            TEvent, sm_impl, TDeps, TSubs>(event, self, deps, subs, current_state);
+      default:
+        return dispatch<N + 1, TMappings>(self, current_state, event, deps, subs, aux::type_list<TStates...>{});
+    }
+  }
+};
+#if defined(__cpp_fold_expressions)
+struct fold_expr {
+  template <class TMappings, int... Ns, class sm_impl, class State, class TEvent, class TDeps, class TSubs, class... TStates>
+  constexpr static bool dispatch_impl(sm_impl &self, State &current_state, aux::index_sequence<Ns...>, const TEvent &event, TDeps &deps,
+                            TSubs &subs, const aux::type_list<TStates...> &) {
+    return ((current_state == Ns
+                 ? get_state_mapping_t<TStates, TMappings, typename sm_impl::has_unexpected_events>::template execute<
+                       TEvent, sm_impl, TDeps, TSubs>(event, self, deps, subs, current_state)
+                 : false) ||
+            ...);
+  }
+  template <int N, class TMappings, class sm_impl, class State, class TEvent, class TDeps, class TSubs, class... TStates>
+  constexpr static bool dispatch(sm_impl &self, State &current_state, const TEvent &event, TDeps &deps, TSubs &subs,
+                       const aux::type_list<TStates...> &states) {
+    return dispatch_impl<TMappings>(self, current_state, aux::make_index_sequence<sizeof...(TStates)>{}, event, deps, subs,
+                                    states);
+  }
+};
+#endif
+}  // namespace policies
+}  // namespace back
+namespace back {
+template <class>
+class sm;
+template <class, class...>
+struct sm_policy;
+struct no_policy;
+namespace policies {
+struct logger_policy__ {};
+template <class T>
+struct logger : aux::pair<logger_policy__, logger<T>> {
+  using type = T;
+};
+template <class>
+struct get_state_name;
+template <class T>
+struct get_state_name<aux::string<T>> {
+  using type = aux::string<T>;
+};
+template <class T, class... Ts>
+struct get_state_name<aux::string<sm<sm_policy<T, Ts...>>>> {
+  using type = typename get_state_name<aux::string<sm_policy<T, Ts...>>>::type;
+};
+template <class T>
+struct get_state_name<aux::string<sm_policy<T>>> {
+  using type = aux::string<T>;
+};
+template <class T, class TName>
+struct get_state_name<aux::string<sm_policy<T, TName>>> {
+  using type = aux::string<T(typename TName::type)>;
+};
+template <class T>
+using get_state_name_t = typename get_state_name<T>::type;
+template <class, class TDeps, class TEvent>
+constexpr void log_process_event(const aux::type<no_policy> &, TDeps &, const TEvent &) {}
+template <class SM, class TLogger, class TDeps, class TEvent>
+constexpr void log_process_event(const aux::type<TLogger> &, TDeps &deps, const TEvent &event) {
+  return static_cast<aux::pool_type<TLogger &> &>(deps).value.template log_process_event<SM>(event);
+}
+template <class, class TDeps, class TSrcState, class TDstState>
+constexpr void log_state_change(const aux::type<no_policy> &, TDeps &, const TSrcState &, const TDstState &) {}
+template <class SM, class TLogger, class TDeps, class TSrcState, class TDstState>
+constexpr void log_state_change(const aux::type<TLogger> &, TDeps &deps, const TSrcState &, const TDstState &) {
+  return static_cast<aux::pool_type<TLogger &> &>(deps).value.template log_state_change<SM>(get_state_name_t<TSrcState>{},
+                                                                                            get_state_name_t<TDstState>{});
+}
+template <class, class TDeps, class TAction, class TEvent>
+constexpr void log_action(const aux::type<no_policy> &, TDeps &, const TAction &, const TEvent &) {}
+template <class SM, class TLogger, class TDeps, class TAction, class TEvent>
+constexpr void log_action(const aux::type<TLogger> &, TDeps &deps, const TAction &action, const TEvent &event) {
+  return static_cast<aux::pool_type<TLogger &> &>(deps).value.template log_action<SM>(action, event);
+}
+template <class SM, class TLogger, class TDeps, class TAction, class TEvent>
+constexpr void log_action(const aux::type<TLogger> &, TDeps &deps, const aux::zero_wrapper<TAction> &action, const TEvent &event) {
+  return static_cast<aux::pool_type<TLogger &> &>(deps).value.template log_action<SM>(action.get(), event);
+}
+template <class, class TDeps, class TGuard, class TEvent>
+constexpr void log_guard(const aux::type<no_policy> &, TDeps &, const TGuard &, const TEvent &, bool) {}
+template <class SM, class TLogger, class TDeps, class TGuard, class TEvent>
+constexpr void log_guard(const aux::type<TLogger> &, TDeps &deps, const TGuard &guard, const TEvent &event, bool result) {
+  return static_cast<aux::pool_type<TLogger &> &>(deps).value.template log_guard<SM>(guard, event, result);
+}
+template <class SM, class TLogger, class TDeps, class TGuard, class TEvent>
+constexpr void log_guard(const aux::type<TLogger> &, TDeps &deps, const aux::zero_wrapper<TGuard> &guard, const TEvent &event,
+               bool result) {
+  return static_cast<aux::pool_type<TLogger &> &>(deps).value.template log_guard<SM>(guard.get(), event, result);
+}
+}  // namespace policies
+}  // namespace back
+namespace back {
+namespace policies {
+struct process_queue_policy__ {};
+template <template <class...> class T>
+struct process_queue : aux::pair<back::policies::process_queue_policy__, process_queue<T>> {
+  template <class U>
+  using rebind = T<U>;
+};
+}  // namespace policies
+}  // namespace back
+namespace back {
+namespace policies {
+struct dont_instantiate_statemachine_class_policy__ {};
+struct dont_instantiate_statemachine_class
+    : aux::pair<dont_instantiate_statemachine_class_policy__, dont_instantiate_statemachine_class> {};
+}  // namespace policies
+}  // namespace back
+
+namespace aux {
+template <class Tsm>
+struct should_not_instantiate_statemachine_class
+    : integral_constant<bool, is_same<typename Tsm::dont_instantiate_statemachine_class_policy,
+                                                back::policies::dont_instantiate_statemachine_class>::value> {};
+
+template <class Tsm>
+struct should_not_subclass_statemachine_class
+    : integral_constant<bool, is_empty<typename Tsm::sm>::value || should_not_instantiate_statemachine_class<Tsm>::value> {};
+} // namespace aux
+
+namespace back {
+namespace policies {
+struct testing_policy__ {};
+struct testing : aux::pair<testing_policy__, testing> {};
+}  // namespace policies
+}  // namespace back
+namespace back {
+namespace policies {
+struct thread_safety_policy__ {
+  constexpr auto create_lock() { return *this; }
+  __BOOST_SML_ZERO_SIZE_ARRAY(aux::byte);
+};
+template <class TLock>
+struct thread_safe : aux::pair<thread_safety_policy__, thread_safe<TLock>> {
+  using type = thread_safe;
+  constexpr auto create_lock() {
+    struct lock_guard {
+      constexpr explicit lock_guard(TLock &lock) : lock_{lock} { lock_.lock(); }
+      ~lock_guard() { lock_.unlock(); }
+      TLock &lock_;
+    };
+    return lock_guard{lock};
+  }
+  TLock lock{};
+};
+}  // namespace policies
+}  // namespace back
+namespace back {
+struct no_policy : policies::thread_safety_policy__ {
+  using type = no_policy;
+  template <class>
+  using rebind = no_policy;
+  template <class...>
+  using defer = no_policy;
+  using const_iterator = no_policy;
+  using flag = no_policy;
+  __BOOST_SML_ZERO_SIZE_ARRAY(aux::byte);
+};
+template <class TDefault, class>
+TDefault get_policy(...);
+template <class, class T, class TPolicy>
+TPolicy get_policy(aux::pair<T, TPolicy> *);
+template <class SM, class... TPolicies>
+struct sm_policy {
+  static_assert(aux::is_same<aux::remove_reference_t<SM>, SM>::value, "SM type can't have qualifiers");
+  using sm = SM;
+  using thread_safety_policy =
+      decltype(get_policy<no_policy, policies::thread_safety_policy__>((aux::inherit<TPolicies...> *)0));
+  using defer_queue_policy = decltype(get_policy<no_policy, policies::defer_queue_policy__>((aux::inherit<TPolicies...> *)0));
+  using process_queue_policy =
+      decltype(get_policy<no_policy, policies::process_queue_policy__>((aux::inherit<TPolicies...> *)0));
+  using logger_policy = decltype(get_policy<no_policy, policies::logger_policy__>((aux::inherit<TPolicies...> *)0));
+  using testing_policy = decltype(get_policy<no_policy, policies::testing_policy__>((aux::inherit<TPolicies...> *)0));
+  using dont_instantiate_statemachine_class_policy = decltype(get_policy<no_policy, policies::dont_instantiate_statemachine_class_policy__>((aux::inherit<TPolicies...> *)0));
+  using default_dispatch_policy = policies::switch_stm;
+  using dispatch_policy =
+      decltype(get_policy<default_dispatch_policy, policies::dispatch_policy__>((aux::inherit<TPolicies...> *)0));
+  template <class T>
+  using rebind = typename rebind_impl<T, TPolicies...>::type;
+};
+}  // namespace back
+namespace concepts {
+struct callable_fallback {
+  void operator()();
+};
+template <class T>
+aux::false_type test_callable(aux::non_type<void (callable_fallback::*)(), &T::operator()> *);
+template <class>
+aux::true_type test_callable(...);
+template <class, class T>
+struct callable
+    : decltype(test_callable<aux::inherit<aux::conditional_t<__is_class(T), T, aux::none_type>, callable_fallback>>(0)) {};
+template <class T, class R, class TBase, class... TArgs>
+struct callable<T, R (TBase::*)(TArgs...)> : aux::true_type {};
+template <class T, class R, class TBase, class... TArgs>
+struct callable<T, R (TBase::*)(TArgs...) const> : aux::true_type {};
+#if defined(__cpp_noexcept_function_type)
+template <class T, class R, class TBase, class... TArgs>
+struct callable<T, R (TBase::*)(TArgs...) noexcept> : aux::true_type {};
+template <class T, class R, class TBase, class... TArgs>
+struct callable<T, R (TBase::*)(TArgs...) const noexcept> : aux::true_type {};
+#endif
+}  // namespace concepts
+namespace concepts {
+template <class T>
+decltype(aux::declval<T>().operator()()) composable_impl(int);
+template <class>
+void composable_impl(...);
+template <class T>
+struct composable : aux::is<aux::pool, decltype(composable_impl<T>(0))> {};
+}  // namespace concepts
+#if !defined(BOOST_SML_DISABLE_EXCEPTIONS)
+#if !(defined(__cpp_exceptions) || defined(__EXCEPTIONS) || defined(_CPPUNWIND))
+#define BOOST_SML_DISABLE_EXCEPTIONS true
+#else
+#define BOOST_SML_DISABLE_EXCEPTIONS false
+#endif
+#endif
+namespace back {
+template <class Tsm>
+struct sm_impl : aux::conditional_t<aux::should_not_subclass_statemachine_class<Tsm>::value, aux::none_type, typename Tsm::sm> {
+  using sm_t = typename Tsm::sm;
+  using thread_safety_t = typename Tsm::thread_safety_policy::type;
+  template <class T>
+  using defer_queue_t = typename Tsm::defer_queue_policy::template rebind<T>;
+  using defer_flag_t = typename Tsm::defer_queue_policy::flag;
+  template <class T>
+  using process_queue_t = typename Tsm::process_queue_policy::template rebind<T>;
+  using logger_t = typename Tsm::logger_policy::type;
+  using dispatch_t = typename Tsm::dispatch_policy;
+  using transitions_t = decltype(aux::declval<sm_t>().operator()());
+  using states_t = aux::apply_t<aux::unique_t, aux::apply_t<get_states, transitions_t>>;
+  using states_ids_t = aux::apply_t<aux::type_id, states_t>;
+  using initial_states_t = aux::apply_t<aux::unique_t, aux::apply_t<get_initial_states, transitions_t>>;
+  using initial_states_ids_t = aux::apply_t<aux::type_id, initial_states_t>;
+  using history_states_t = aux::apply_t<get_history_states, transitions_t>;
+  using has_history_states =
+      aux::integral_constant<bool, aux::size<initial_states_t>::value != aux::size<history_states_t>::value>;
+  using sub_internal_events_t = aux::apply_t<aux::unique_t, aux::apply_t<get_sub_internal_events, transitions_t>>;
+  using events_t = aux::apply_t<aux::unique_t, aux::join_t<sub_internal_events_t, aux::apply_t<get_all_events, transitions_t>>>;
+  using events_ids_t = aux::apply_t<aux::inherit, events_t>;
+  using has_unexpected_events = typename aux::is_base_of<unexpected, aux::apply_t<aux::inherit, events_t>>::type;
+  using has_entry_exits = typename aux::is_base_of<entry_exit, aux::apply_t<aux::inherit, events_t>>::type;
+  using should_not_instantiate_statemachine_class_t = aux::should_not_instantiate_statemachine_class<Tsm>;
+  using defer_t = defer_queue_t<aux::apply_t<queue_event, events_t>>;
+  using process_t = process_queue_t<aux::apply_t<queue_event, events_t>>;
+  using deps = aux::apply_t<merge_deps, transitions_t>;
+  using state_t = aux::conditional_t<(aux::size<states_t>::value > 0xFF), unsigned short, aux::byte>;
+  static constexpr auto regions = aux::size<initial_states_t>::value;
+  static_assert(regions > 0, "At least one initial state is required");
+#if !BOOST_SML_DISABLE_EXCEPTIONS
+  using exceptions = aux::apply_t<aux::unique_t, aux::apply_t<get_exceptions, events_t>>;
+  using has_exceptions = aux::integral_constant<bool, (aux::size<exceptions>::value > 0)>;
+#endif
+  struct mappings : mappings_t<transitions_t> {};
+  template <class TPool>
+  constexpr sm_impl(aux::init, const TPool &p) : sm_impl{p, aux::should_not_subclass_statemachine_class<Tsm>{}} {}
+  template <class TPool>
+  constexpr sm_impl(const TPool &p, aux::false_type) : sm_t{aux::try_get<sm_t>(&p)}, transitions_{(*this)()} {
+    initialize(typename sm_impl<Tsm>::initial_states_t{});
+  }
+
+  template <class T, class TPool>
+  constexpr decltype(auto) try_get_without_instantiating(const TPool &p) const {
+    static_assert(!(should_not_instantiate_statemachine_class_t::value &&
+              aux::would_instantiate_missing_ctor_parameter<sm_t, decltype(&p)>()),
+            "When policy sml::dont_instantiate_statemachine_class is used, you have to provide a reference to an "
+            "instance of the transition table type (boost::sml::sm< your_transition_table_type >) "
+            "as well as a reference to instances of all sub-statemachine types as constructor parameters like this: \n"
+            "boost::sml::sm< your_transition_table_type , sml::dont_instantiate_statemachine_class >{\n"
+            "    your_transition_table_instance\n"
+            "}"
+  );
+
+    return aux::try_get<T>(&p)();
+  }
+
+  template <class TPool>
+  constexpr sm_impl(const TPool &p, aux::true_type) : transitions_{ try_get_without_instantiating<sm_t>(p) } {
+    initialize(typename sm_impl<Tsm>::initial_states_t{});
+  }
+  template <class TEvent, class TDeps, class TSubs>
+  constexpr bool process_event(const TEvent &event, TDeps &deps, TSubs &subs) {
+    const auto lock = thread_safety_.create_lock();
+    (void)lock;
+    bool changed = false;
+    state_t old = current_state_[0];
+    bool handled = process_internal_events(event, deps, subs);
+    bool queued_handled = true;
+    do {
+      do {
+        while (process_internal_events(anonymous{}, deps, subs)) {
+        }
+        changed = (old != current_state_[0]);
+        old = current_state_[0];
+      } while (process_defer_events(deps, subs, changed, aux::type<defer_queue_t<TEvent>>{}, events_t{}));
+    } while (process_queued_events(deps, subs, queued_handled, aux::type<process_queue_t<TEvent>>{}, events_t{}));
+    return handled && queued_handled;
+  }
+  constexpr void initialize(const aux::type_list<> &) {}
+  template <class TState>
+  constexpr void initialize(const aux::type_list<TState> &) {
+    current_state_[0] = aux::get_id<state_t, TState>((states_ids_t *)0);
+  }
+  template <class... TStates>
+  constexpr void initialize(const aux::type_list<TStates...> &) {
+    auto region = 0;
+#if defined(__cpp_fold_expressions)
+    ((current_state_[region++] = aux::get_id<state_t, TStates>((states_ids_t *)0)), ...);
+#else
+    (void)aux::swallow{0, (current_state_[region++] = aux::get_id<state_t, TStates>((states_ids_t *)0), 0)...};
+#endif
+  }
+  template <class TDeps, class TSubs>
+  constexpr void start(TDeps &deps, TSubs &subs) {
+    process_event(on_entry<_, initial>{}, deps, subs);
+  }
+  template <class TEvent, class TDeps, class TSubs, class... Ts,
+            __BOOST_SML_REQUIRES(!aux::is_base_of<get_generic_t<TEvent>, events_ids_t>::value &&
+                                 !aux::is_base_of<get_mapped_t<TEvent>, events_ids_t>::value &&
+                                 !aux::is_same<get_event_t<TEvent>, initial>::value)>
+  constexpr bool process_internal_events(const TEvent &, TDeps &, TSubs &, Ts &&...) {
+    return false;
+  }
+  template <class TEvent, class TDeps, class TSubs, class... Ts,
+            __BOOST_SML_REQUIRES(!aux::is_base_of<get_generic_t<TEvent>, events_ids_t>::value &&
+                                 !aux::is_base_of<get_mapped_t<TEvent>, events_ids_t>::value &&
+                                 aux::is_same<get_event_t<TEvent>, initial>::value)>
+  constexpr bool process_internal_events(const TEvent &event, TDeps &deps, TSubs &subs) {
+    policies::log_process_event<sm_t>(aux::type<logger_t>{}, deps, event);
+#if BOOST_SML_DISABLE_EXCEPTIONS
+    return process_event_impl<get_event_mapping_t<get_generic_t<TEvent>, mappings>>(event, deps, subs, states_t{},
+                                                                                    aux::make_index_sequence<regions>{});
+#else
+    return process_event_except_impl<get_event_mapping_t<get_generic_t<TEvent>, mappings>>(event, deps, subs, has_exceptions{});
+#endif
+  }
+  template <class TEvent, class TDeps, class TSubs,
+            __BOOST_SML_REQUIRES(aux::is_base_of<get_generic_t<TEvent>, events_ids_t>::value &&
+                                 !aux::is_base_of<get_mapped_t<TEvent>, events_ids_t>::value)>
+  constexpr bool process_internal_events(const TEvent &event, TDeps &deps, TSubs &subs) {
+    policies::log_process_event<sm_t>(aux::type<logger_t>{}, deps, event);
+#if BOOST_SML_DISABLE_EXCEPTIONS
+    return process_event_impl<get_event_mapping_t<get_generic_t<TEvent>, mappings>>(event, deps, subs, states_t{},
+                                                                                    aux::make_index_sequence<regions>{});
+#else
+    return process_event_except_impl<get_event_mapping_t<get_generic_t<TEvent>, mappings>>(event, deps, subs, has_exceptions{});
+#endif
+  }
+  template <class TEvent, class TDeps, class TSubs,
+            __BOOST_SML_REQUIRES(aux::is_base_of<get_mapped_t<TEvent>, events_ids_t>::value)>
+  constexpr bool process_internal_events(const TEvent &event, TDeps &deps, TSubs &subs) {
+    policies::log_process_event<sm_t>(aux::type<logger_t>{}, deps, event);
+#if BOOST_SML_DISABLE_EXCEPTIONS
+    return process_event_impl<get_event_mapping_t<get_mapped_t<TEvent>, mappings>>(event, deps, subs, states_t{},
+                                                                                   aux::make_index_sequence<regions>{});
+#else
+    return process_event_except_impl<get_event_mapping_t<get_mapped_t<TEvent>, mappings>>(event, deps, subs, has_exceptions{});
+#endif
+  }
+  template <class TEvent, class TDeps, class TSubs, class... Ts,
+            __BOOST_SML_REQUIRES(!aux::is_base_of<get_generic_t<TEvent>, events_ids_t>::value &&
+                                 !aux::is_base_of<get_mapped_t<TEvent>, events_ids_t>::value)>
+  constexpr bool process_internal_event(const TEvent &, TDeps &, TSubs &, Ts &&...) {
+    return false;
+  }
+  template <class TEvent, class TDeps, class TSubs,
+            __BOOST_SML_REQUIRES(!aux::is_base_of<get_generic_t<TEvent>, events_ids_t>::value)>
+  constexpr bool process_internal_generic_event(const TEvent &, TDeps &, TSubs &, state_t &) {
+    return false;
+  }
+  template <class TEvent, class TDeps, class TSubs,
+            __BOOST_SML_REQUIRES(aux::is_base_of<get_generic_t<TEvent>, events_ids_t>::value)>
+  constexpr bool process_internal_generic_event(const TEvent &event, TDeps &deps, TSubs &subs, state_t &current_state) {
+    policies::log_process_event<sm_t>(aux::type<logger_t>{}, deps, event);
+#if BOOST_SML_DISABLE_EXCEPTIONS
+    return process_event_impl<get_event_mapping_t<get_generic_t<TEvent>, mappings>>(event, deps, subs, states_t{},
+                                                                                    current_state);
+#else
+    return process_event_except_impl<get_event_mapping_t<get_generic_t<TEvent>, mappings>>(event, deps, subs, current_state,
+                                                                                          has_exceptions{});
+#endif
+  }
+  template <class TEvent, class TDeps, class TSubs,
+            __BOOST_SML_REQUIRES(aux::is_base_of<get_generic_t<TEvent>, events_ids_t>::value &&
+                                 !aux::is_base_of<get_mapped_t<TEvent>, events_ids_t>::value)>
+  constexpr bool process_internal_event(const TEvent &event, TDeps &deps, TSubs &subs, state_t &current_state) {
+    return process_internal_generic_event(event, deps, subs, current_state);
+  }
+  template <class TEvent, class TDeps, class TSubs,
+            __BOOST_SML_REQUIRES(aux::is_base_of<get_mapped_t<TEvent>, events_ids_t>::value)>
+  constexpr bool process_internal_event(const TEvent &event, TDeps &deps, TSubs &subs, state_t &current_state) {
+    policies::log_process_event<sm_t>(aux::type<logger_t>{}, deps, event);
+#if BOOST_SML_DISABLE_EXCEPTIONS
+    return process_event_impl<get_event_mapping_t<get_mapped_t<TEvent>, mappings>>(event, deps, subs, states_t{}, current_state)
+#else
+    return process_event_except_impl<get_event_mapping_t<get_mapped_t<TEvent>, mappings>>(event, deps, subs, current_state,
+                                                                                         has_exceptions{})
+#endif
+           || process_internal_generic_event(event, deps, subs, current_state);
+  }
+  template <class TMappings, class TEvent, class TDeps, class TSubs, class... TStates>
+  constexpr bool process_event_impl(const TEvent &event, TDeps &deps, TSubs &subs, const aux::type_list<TStates...> &states,
+                          aux::index_sequence<0>) {
+    return dispatch_t::template dispatch<0, TMappings>(*this, current_state_[0], event, deps, subs, states);
+  }
+  template <class TMappings, class TEvent, class TDeps, class TSubs, class... TStates, int... Ns>
+  constexpr bool process_event_impl(const TEvent &event, TDeps &deps, TSubs &subs, const aux::type_list<TStates...> &states,
+                          aux::index_sequence<Ns...>) {
+    auto handled = false;
+#if defined(__cpp_fold_expressions)
+    ((handled |= dispatch_t::template dispatch<0, TMappings>(*this, current_state_[Ns], event, deps, subs, states)), ...);
+#else
+    (void)aux::swallow{
+        0,
+        (handled |= dispatch_t::template dispatch<0, TMappings>(*this, current_state_[Ns], event, deps, subs, states), 0)...};
+#endif
+    return handled;
+  }
+  template <class TMappings, class TEvent, class TDeps, class TSubs, class... TStates>
+  constexpr bool process_event_impl(const TEvent &event, TDeps &deps, TSubs &subs, const aux::type_list<TStates...> &states,
+                          state_t &current_state) {
+    return dispatch_t::template dispatch<0, TMappings>(*this, current_state, event, deps, subs, states);
+  }
+#if !BOOST_SML_DISABLE_EXCEPTIONS
+  template <class TMappings, class TEvent, class TDeps, class TSubs>
+  constexpr bool process_event_except_impl(const TEvent &event, TDeps &deps, TSubs &subs, aux::false_type) {
+    return process_event_impl<TMappings>(event, deps, subs, states_t{}, aux::make_index_sequence<regions>{});
+  }
+  template <class TMappings, class TEvent, class TDeps, class TSubs>
+  constexpr bool process_event_except_impl(const TEvent &event, TDeps &deps, TSubs &subs, state_t &current_state, aux::false_type) {
+    return process_event_impl<TMappings>(event, deps, subs, states_t{}, current_state);
+  }
+  template <class TMappings, class TEvent, class TDeps, class TSubs>
+  bool process_event_except_impl(const TEvent &event, TDeps &deps, TSubs &subs, state_t &current_state,
+                                aux::true_type) noexcept {
+    try {
+      return process_event_impl<TMappings>(event, deps, subs, states_t{}, current_state);
+    } catch (...) {
+      return process_exception(deps, subs, exceptions{});
+    }
+  }
+  template <class TMappings, class TEvent, class TDeps, class TSubs>
+  bool process_event_except_impl(const TEvent &event, TDeps &deps, TSubs &subs, aux::true_type) {
+    try {
+      return process_event_impl<TMappings>(event, deps, subs, states_t{}, aux::make_index_sequence<regions>{});
+    } catch (...) {
+      return process_exception(deps, subs, exceptions{});
+    }
+  }
+  template <class TDeps, class TSubs>
+  constexpr bool process_exception(TDeps &deps, TSubs &subs, const aux::type_list<> &) {
+    return process_internal_events(exception<_>{}, deps, subs);
+  }
+  template <class TDeps, class TSubs, class E, class... Es>
+  bool process_exception(TDeps &deps, TSubs &subs, const aux::type_list<E, Es...> &) {
+    try {
+      throw;
+    } catch (const typename E::type &e) {
+      return process_internal_events(E{e}, deps, subs);
+    } catch (...) {
+      return process_exception(deps, subs, aux::type_list<Es...>{});
+    }
+  }
+#endif
+  template <class TDeps, class TSubs, class... TEvents>
+  constexpr bool process_defer_events(TDeps &, TSubs &, const bool, const aux::type<no_policy> &, const aux::type_list<TEvents...> &) {
+    return false;
+  }
+  template <class TDeps, class TSubs, class TEvent>
+  constexpr bool process_event_no_defer(TDeps &deps, TSubs &subs, const void *data) {
+    const auto &event = *static_cast<const TEvent *>(data);
+    bool handled = process_internal_events(event, deps, subs);
+    if (handled && defer_again_) {
+      ++defer_it_;
+    } else {
+      defer_it_ = defer_.erase(defer_it_);
+      defer_end_ = defer_.end();
+    }
+    return handled;
+  }
+  template <class TDeps, class TSubs, class TDeferQueue, class... TEvents>
+  bool process_defer_events(TDeps &deps, TSubs &subs, const bool handled, const aux::type<TDeferQueue> &,
+                            const aux::type_list<TEvents...> &) {
+    bool processed_events = false;
+    if (handled) {
+      using dispatch_table_t = bool (sm_impl::*)(TDeps &, TSubs &, const void *);
+      const static dispatch_table_t dispatch_table[__BOOST_SML_ZERO_SIZE_ARRAY_CREATE(sizeof...(TEvents))] = {
+          &sm_impl::process_event_no_defer<TDeps, TSubs, TEvents>...};
+      defer_processing_ = true;
+      defer_again_ = false;
+      defer_it_ = defer_.begin();
+      defer_end_ = defer_.end();
+      state_t old = current_state_[0];
+      while (defer_it_ != defer_end_) {
+        processed_events |= (this->*dispatch_table[defer_it_->id])(deps, subs, defer_it_->data);
+        defer_again_ = false;
+        if (old != current_state_[0]) {
+          defer_it_ = defer_.begin();
+          old = current_state_[0];
+        }
+      }
+      defer_processing_ = false;
+    }
+    return processed_events;
+  }
+  template <class TDeps, class TSubs, class... TEvents>
+  constexpr bool process_queued_events(TDeps &, TSubs &,  bool &, const aux::type<no_policy> &, const aux::type_list<TEvents...> &) {
+    return false;
+  }
+  template <class TDeps, class TSubs, class TEvent>
+  constexpr bool process_event_no_queue(TDeps &deps, TSubs &subs, const void *data) {
+    const auto &event = *static_cast<const TEvent *>(data);
+    policies::log_process_event<sm_t>(aux::type<logger_t>{}, deps, event);
+#if BOOST_SML_DISABLE_EXCEPTIONS
+    return process_event_impl<get_event_mapping_t<TEvent, mappings>>(event, deps, subs, states_t{},
+                                                                     aux::make_index_sequence<regions>{});
+#else
+    return process_event_except_impl<get_event_mapping_t<TEvent, mappings>>(event, deps, subs, has_exceptions{});
+#endif
+  }
+  template <class TDeps, class TSubs, class TDeferQueue, class... TEvents>
+  bool process_queued_events(TDeps &deps, TSubs &subs, bool &queued_handled, const aux::type<TDeferQueue> &, const aux::type_list<TEvents...> &) {
+    using dispatch_table_t = bool (sm_impl::*)(TDeps &, TSubs &, const void *);
+    const static dispatch_table_t dispatch_table[__BOOST_SML_ZERO_SIZE_ARRAY_CREATE(sizeof...(TEvents))] = {
+        &sm_impl::process_event_no_queue<TDeps, TSubs, TEvents>...};
+    bool wasnt_empty = !process_.empty();
+    while (!process_.empty()) {
+      queued_handled &= (this->*dispatch_table[process_.front().id])(deps, subs, process_.front().data);
+      process_.pop();
+    }
+    return wasnt_empty;
+  }
+  template <class TVisitor, class... TStates>
+  constexpr void visit_current_states(const TVisitor &visitor, const aux::type_list<TStates...> &, aux::index_sequence<0>) const {
+    using dispatch_table_t = void (*)(const TVisitor &);
+    const dispatch_table_t dispatch_table[__BOOST_SML_ZERO_SIZE_ARRAY_CREATE(sizeof...(TStates))] = {
+        &sm_impl::visit_state<TVisitor, TStates>...};
+    dispatch_table[current_state_[0]](visitor);
+  }
+  template <class TVisitor, class... TStates, int... Ns>
+  constexpr void visit_current_states(const TVisitor &visitor, const aux::type_list<TStates...> &, aux::index_sequence<Ns...>) const {
+    using dispatch_table_t = void (*)(const TVisitor &);
+    const dispatch_table_t dispatch_table[__BOOST_SML_ZERO_SIZE_ARRAY_CREATE(sizeof...(TStates))] = {
+        &sm_impl::visit_state<TVisitor, TStates>...};
+#if defined(__cpp_fold_expressions)
+    (dispatch_table[current_state_[Ns]](visitor), ...);
+#else
+    (void)aux::swallow{0, (dispatch_table[current_state_[Ns]](visitor), 0)...};
+#endif
+  }
+  template <class TVisitor, class TState>
+  constexpr static void visit_state(const TVisitor &visitor) {
+    visitor(aux::string<TState>{});
+  }
+  constexpr bool is_terminated() const { return is_terminated_impl(aux::make_index_sequence<regions>{}); }
+  constexpr bool is_terminated_impl(aux::index_sequence<0>) const {
+    return current_state_[0] == aux::get_id<state_t, terminate_state>((states_ids_t *)0);
+  }
+  template <int... Ns>
+  constexpr bool is_terminated_impl(aux::index_sequence<Ns...>) const {
+#if defined(__cpp_fold_expressions)
+    return ((current_state_[Ns] == aux::get_id<state_t, terminate_state>((states_ids_t *)0)) && ...);
+#else
+    auto result = true;
+    (void)aux::swallow{0, (result &= current_state_[Ns] == aux::get_id<state_t, terminate_state>((states_ids_t *)0))...};
+    return result;
+#endif
+  }
+  transitions_t transitions_{};
+  state_t current_state_[regions]{};
+  thread_safety_t thread_safety_{};
+  defer_t defer_{};
+  process_t process_{};
+  defer_flag_t defer_processing_ = defer_flag_t{};
+  defer_flag_t defer_again_ = defer_flag_t{};
+  typename defer_t::const_iterator defer_it_{};
+  typename defer_t::const_iterator defer_end_{};
+};
+template <class Tsm>
+class sm {
+  using sm_t = typename Tsm::sm;
+  using logger_t = typename Tsm::logger_policy::type;
+  using logger_dep_t =
+      aux::conditional_t<aux::is_same<no_policy, logger_t>::value, aux::type_list<>, aux::type_list<logger_t &>>;
+  using transitions_t = decltype(aux::declval<sm_t>().operator()());
+  static_assert(concepts::composable<sm_t>::value, "Composable constraint is not satisfied!");
+
+ public:
+  using states = aux::apply_t<aux::unique_t, aux::apply_t<get_states, transitions_t>>;
+  using state_machines = aux::apply_t<get_sub_sms, states>;
+  using events = aux::apply_t<aux::unique_t, aux::apply_t<get_all_events, transitions_t>>;
+  using transitions = aux::apply_t<aux::type_list, transitions_t>;
+
+ private:
+  using sm_all_t = aux::apply_t<get_non_empty_t, aux::join_t<
+      aux::conditional_t<
+            aux::is_same<no_policy, typename Tsm::dont_instantiate_statemachine_class_policy>::value,
+            aux::type_list<sm_t>,
+            aux::none_type>,
+      aux::apply_t<get_sm_t, state_machines>>>;
+
+  using sub_sms_t =
+      aux::apply_t<aux::pool,
+                   typename convert_to_sm<Tsm, aux::apply_t<aux::unique_t, aux::apply_t<get_sub_sms, states>>>::type>;
+  using deps = aux::apply_t<merge_deps, transitions_t>;
+  using deps_t =
+      aux::apply_t<aux::pool,
+                   aux::apply_t<aux::unique_t, aux::join_t<deps, sm_all_t, logger_dep_t, aux::apply_t<merge_deps, sub_sms_t>>>>;
+  struct events_ids : aux::apply_t<aux::inherit, events> {};
+
+ public:
+  constexpr sm() : deps_{aux::init{}, aux::pool<>{}}, sub_sms_{aux::pool<>{}} { aux::get<sm_impl<Tsm>>(sub_sms_).start(deps_, sub_sms_); }
+  template <class TDeps, __BOOST_SML_REQUIRES(!aux::is_same<aux::remove_reference_t<TDeps>, sm>::value)>
+  constexpr explicit sm(TDeps &&deps) : deps_{aux::init{}, aux::pool<TDeps>{deps}}, sub_sms_{aux::pool<TDeps>{deps}} {
+    aux::get<sm_impl<Tsm>>(sub_sms_).start(deps_, sub_sms_);
+  }
+  template <class... TDeps, __BOOST_SML_REQUIRES((sizeof...(TDeps) > 1) && aux::is_unique_t<TDeps...>::value)>
+  constexpr explicit sm(TDeps &&... deps) : deps_{aux::init{}, aux::pool<TDeps...>{deps...}}, sub_sms_{aux::pool<TDeps...>{deps...}} {
+    aux::get<sm_impl<Tsm>>(sub_sms_).start(deps_, sub_sms_);
+  }
+  constexpr sm(aux::init, deps_t &deps) : deps_{deps}, sub_sms_{deps} { aux::get<sm_impl<Tsm>>(sub_sms_).start(deps_, sub_sms_); }
+  constexpr sm(const sm &) = default;
+  constexpr sm(sm &&) = default;
+  constexpr sm &operator=(const sm &) = default;
+  constexpr sm &operator=(sm &&) = default;
+  template <class TEvent, __BOOST_SML_REQUIRES(aux::is_base_of<TEvent, events_ids>::value)>
+  constexpr bool process_event(const TEvent &event) {
+    return aux::get<sm_impl<Tsm>>(sub_sms_).process_event(event, deps_, sub_sms_);
+  }
+  template <class TEvent, __BOOST_SML_REQUIRES(!aux::is_base_of<TEvent, events_ids>::value)>
+  constexpr bool process_event(const TEvent &event) {
+    return aux::get<sm_impl<Tsm>>(sub_sms_).process_event(unexpected_event<_, TEvent>{event}, deps_, sub_sms_);
+  }
+  template <class T = aux::identity<sm_t>, class TVisitor, __BOOST_SML_REQUIRES(concepts::callable<void, TVisitor>::value)>
+  constexpr void visit_current_states(const TVisitor &visitor) const {
+    using type = typename T::type;
+    using sm_impl_t = sm_impl<typename Tsm::template rebind<type>>;
+    using states_t = typename sm_impl_t::states_t;
+    constexpr auto regions = sm_impl_t::regions;
+    aux::cget<sm_impl_t>(sub_sms_).visit_current_states(visitor, states_t{}, aux::make_index_sequence<regions>{});
+  }
+  template <class T = aux::identity<sm_t>, class TState,
+            __BOOST_SML_REQUIRES(sm_impl<typename Tsm::template rebind<typename T::type>>::regions == 1)>
+  constexpr bool is(const TState &) const {
+    using type = typename T::type;
+    using sm_impl_t = sm_impl<typename Tsm::template rebind<type>>;
+    using state_t = typename sm_impl_t::state_t;
+    using states_ids_t = typename sm_impl_t::states_ids_t;
+    return aux::get_id<state_t, typename TState::type>((states_ids_t *)0) == aux::cget<sm_impl_t>(sub_sms_).current_state_[0];
+  }
+  template <class T = aux::identity<sm_t>, class TState,
+            __BOOST_SML_REQUIRES(sm_impl<typename Tsm::template rebind<typename T::type>>::regions != 1)>
+  constexpr bool is(const TState &) const {
+    using type = typename T::type;
+    using sm_impl_t = sm_impl<typename Tsm::template rebind<type>>;
+    using state_t = typename sm_impl_t::state_t;
+    using states_ids_t = typename sm_impl_t::states_ids_t;
+    auto result = false;
+    visit_current_states<T>([&](auto state) {
+      (void)state;
+      result |= (aux::get_id<state_t, typename TState::type>((states_ids_t *)0) ==
+                 aux::get_id<state_t, typename decltype(state)::type>((states_ids_t *)0));
+    });
+    return result;
+  }
+  template <class T = aux::identity<sm_t>, template <class...> class TState>
+  constexpr bool is(const TState<terminate_state> &) const {
+    using type = typename T::type;
+    using sm_impl_t = sm_impl<typename Tsm::template rebind<type>>;
+    using state_t = typename sm_impl_t::state_t;
+    using states_ids_t = typename sm_impl_t::states_ids_t;
+    auto result = false;
+    visit_current_states<T>([&](auto state) {
+      (void)state;
+      result |= (aux::get_id<state_t, terminate_state>((states_ids_t *)0) ==
+                 aux::get_id<state_t, typename decltype(state)::type>((states_ids_t *)0));
+    });
+    return result;
+  }
+  template <class T = aux::identity<sm_t>, class... TStates,
+            __BOOST_SML_REQUIRES(sizeof...(TStates) == sm_impl<typename Tsm::template rebind<typename T::type>>::regions)>
+  constexpr bool is(const TStates &...) const {
+    using type = typename T::type;
+    using sm_impl_t = sm_impl<typename Tsm::template rebind<type>>;
+    using states_ids_t = typename sm_impl_t::states_ids_t;
+    using state_t = typename sm_impl_t::state_t;
+    auto result = true;
+    auto i = 0;
+    state_t state_ids[] = {aux::get_id<state_t, typename TStates::type>((states_ids_t *)0)...};
+    visit_current_states<T>([&](auto state) {
+      (void)state;
+      result &= (aux::get_id<state_t, typename decltype(state)::type>((states_ids_t *)0) == state_ids[i++]);
+    });
+    return result;
+  }
+  template <class T = aux::identity<sm_t>, class... TStates,
+            __BOOST_SML_REQUIRES(!aux::is_same<no_policy, typename Tsm::testing_policy>::value && aux::always<T>::value)>
+  constexpr void set_current_states(const TStates &...) {
+    using type = typename T::type;
+    using sm_impl_t = sm_impl<typename Tsm::template rebind<type>>;
+    using states_ids_t = typename sm_impl_t::states_ids_t;
+    using state_t = typename sm_impl_t::state_t;
+    auto &sm = aux::get<sm_impl_t>(sub_sms_);
+    auto region = 0;
+#if defined(__cpp_fold_expressions)
+    ((sm.current_state_[region++] = aux::get_id<state_t, typename TStates::type>((states_ids_t *)0)), ...);
+#else
+    (void)aux::swallow{0,
+                       (sm.current_state_[region++] = aux::get_id<state_t, typename TStates::type>((states_ids_t *)0), 0)...};
+#endif
+  }
+  template <class T>
+  constexpr operator T &() {
+    return aux::get<sm_impl<typename Tsm::template rebind<T>>>(sub_sms_);
+  }
+  template <class T>
+  constexpr operator const T &() {
+    return aux::cget<sm_impl<typename Tsm::template rebind<T>>>(sub_sms_);
+  }
+
+ private:
+  deps_t deps_;
+  sub_sms_t sub_sms_;
+};
+}  // namespace back
+namespace front {
+struct operator_base {};
+struct action_base {};
+template <class TRootSM, class... TSubSMs>
+TRootSM get_root_sm_impl(aux::pool<TRootSM, TSubSMs...> *);
+template <class TSubs>
+using get_root_sm_t = decltype(get_root_sm_impl((TSubs *)0));
+template <class, class>
+aux::type_list<action_base> args1__(...);
+template <class T, class E>
+auto args1__(int) -> aux::function_traits_t<decltype(&T::operator())>;
+template <class T, class E>
+auto args__(int) -> aux::function_traits_t<decltype(&T::__BOOST_SML_TEMPLATE_KEYWORD operator()<back::get_event_t<E>>)>;
+template <class T, class E>
+auto args__(...) -> decltype(args1__<T, E>(0));
+template <class T, class E>
+using args_t = decltype(args__<T, E>(0));
+template <class T, class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<T> &, const TEvent &, Tsm &, TDeps &deps) {
+  return aux::get<T>(deps);
+}
+template <class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<TEvent> &, const TEvent &event, Tsm &, TDeps &) {
+  return event;
+}
+template <class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<const TEvent &> &, const TEvent &event, Tsm &, TDeps &) {
+  return event;
+}
+template <class T, class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<const TEvent &> &, const back::unexpected_event<T, TEvent> &event, Tsm &, TDeps &) {
+  return event.event_;
+}
+template <class T, class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<const TEvent &> &, const back::on_entry<T, TEvent> &event, Tsm &, TDeps &) {
+  return event.event_;
+}
+template <class T, class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<const TEvent &> &, const back::on_exit<T, TEvent> &event, Tsm &, TDeps &) {
+  return event.event_;
+}
+template <class T, class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<const TEvent &> &, const back::exception<T, TEvent> &event, Tsm &, TDeps &) {
+  return event.exception_;
+}
+template <class... TEvents, class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<back::defer<TEvents...>> &, const TEvent, Tsm &sm, TDeps &) {
+  return back::defer<TEvents...>{sm.defer_};
+}
+template <class... TEvents, class TEvent, class Tsm, class TDeps>
+constexpr decltype(auto) get_arg(const aux::type<back::process<TEvents...>> &, const TEvent, Tsm &sm, TDeps &) {
+  return back::process<TEvents...>{sm.process_};
+}
+template <class, class, class>
+struct call;
+template <class TEvent>
+struct call<TEvent, aux::type_list<>, back::no_policy> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  constexpr static auto execute(T object, const TEvent &, Tsm &, TDeps &, TSubs &) {
+    return object();
+  }
+};
+template <class TEvent, class TLogger>
+struct call<TEvent, aux::type_list<>, TLogger> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  constexpr static auto execute(T object, const TEvent &event, Tsm &, TDeps &deps, TSubs &) {
+    using result_type = decltype(object());
+    return execute_impl<typename Tsm::sm_t>(aux::type<result_type>{}, object, event, deps);
+  }
+  template <class Tsm, class T, class TDeps>
+  constexpr static auto execute_impl(const aux::type<bool> &, T object, const TEvent &event, TDeps &deps) {
+    const auto result = object();
+    back::policies::log_guard<Tsm>(aux::type<TLogger>{}, deps, object, event, result);
+    return result;
+  }
+  template <class Tsm, class T, class TDeps>
+  constexpr static auto execute_impl(const aux::type<void> &, T object, const TEvent &event, TDeps &deps) {
+    back::policies::log_action<Tsm>(aux::type<TLogger>{}, deps, object, event);
+    object();
+  }
+};
+template <class TEvent>
+struct call<TEvent, aux::type_list<TEvent>, back::no_policy> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  constexpr static auto execute(T object, const TEvent &event, Tsm &, TDeps &, TSubs &) {
+    return object(event);
+  }
+};
+template <class TEvent, class TLogger>
+struct call<TEvent, aux::type_list<TEvent>, TLogger> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  constexpr static auto execute(T object, const TEvent &event, Tsm &, TDeps &deps, TSubs &) {
+    using result_type = decltype(object(event));
+    return execute_impl<typename Tsm::sm_t>(aux::type<result_type>{}, object, event, deps);
+  }
+  template <class Tsm, class T, class TDeps>
+  constexpr static auto execute_impl(const aux::type<bool> &, T object, const TEvent &event, TDeps &deps) {
+    const auto result = object(event);
+    back::policies::log_guard<Tsm>(aux::type<TLogger>{}, deps, object, event, result);
+    return result;
+  }
+  template <class Tsm, class T, class TDeps>
+  constexpr static auto execute_impl(const aux::type<void> &, T object, const TEvent &event, TDeps &deps) {
+    back::policies::log_action<Tsm>(aux::type<TLogger>{}, deps, object, event);
+    object(event);
+  }
+};
+template <class TEvent>
+struct call<TEvent, aux::type_list<action_base>, back::no_policy> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  static auto execute(T object, const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+    return object(event, sm, deps, subs);
+  }
+};
+template <class TEvent, class TLogger>
+struct call<TEvent, aux::type_list<action_base>, TLogger> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  constexpr static auto execute(T object, const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+    return object(event, sm, deps, subs);
+  }
+};
+template <class TEvent, class... Ts>
+struct call<TEvent, aux::type_list<Ts...>, back::no_policy> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  constexpr static auto execute(T object, const TEvent &event, Tsm &sm, TDeps &deps, TSubs &) {
+    return object(get_arg(aux::type<Ts>{}, event, sm, deps)...);
+  }
+};
+template <class TEvent, class... Ts, class TLogger>
+struct call<TEvent, aux::type_list<Ts...>, TLogger> {
+  template <class T, class Tsm, class TDeps, class TSubs>
+  constexpr static auto execute(T object, const TEvent &event, Tsm &sm, TDeps &deps, TSubs &) {
+    using result_type = decltype(object(get_arg(aux::type<Ts>{}, event, sm, deps)...));
+    return execute_impl<typename Tsm::sm_t>(aux::type<result_type>{}, object, event, sm, deps);
+  }
+  template <class Tsm, class T, class SM, class TDeps>
+  constexpr static auto execute_impl(const aux::type<bool> &, T object, const TEvent &event, SM &sm, TDeps &deps) {
+    const auto result = object(get_arg(aux::type<Ts>{}, event, sm, deps)...);
+    back::policies::log_guard<Tsm>(aux::type<TLogger>{}, deps, object, event, result);
+    return result;
+  }
+  template <class Tsm, class T, class SM, class TDeps>
+  constexpr static auto execute_impl(const aux::type<void> &, T object, const TEvent &event, SM &sm, TDeps &deps) {
+    back::policies::log_action<Tsm>(aux::type<TLogger>{}, deps, object, event);
+    object(get_arg(aux::type<Ts>{}, event, sm, deps)...);
+  }
+};
+template <class... Ts>
+class seq_ : operator_base {
+ public:
+  constexpr explicit seq_(Ts... ts) : a(ts...) {}
+  template <class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr void operator()(const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+    for_all(aux::make_index_sequence<sizeof...(Ts)>{}, event, sm, deps, subs);
+  }
+
+ private:
+  template <int... Ns, class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr void for_all(const aux::index_sequence<Ns...> &, const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+#if defined(__cpp_fold_expressions)
+    (call<TEvent, args_t<Ts, TEvent>, typename Tsm::logger_t>::execute(aux::get_by_id<Ns>(&a), event, sm, deps, subs), ...);
+#else
+    (void)aux::swallow{
+        0, (call<TEvent, args_t<Ts, TEvent>, typename Tsm::logger_t>::execute(aux::get_by_id<Ns>(&a), event, sm, deps, subs),
+            0)...};
+#endif
+  }
+  aux::tuple<Ts...> a;
+};
+template <class... Ts>
+class and_ : operator_base {
+ public:
+  constexpr explicit and_(Ts... ts) : g(ts...) {}
+  template <class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr auto operator()(const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+    return for_all(aux::make_index_sequence<sizeof...(Ts)>{}, event, sm, deps, subs);
+  }
+
+ private:
+  template <int... Ns, class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr auto for_all(const aux::index_sequence<Ns...> &, const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+#if defined(__cpp_fold_expressions)
+    return (call<TEvent, args_t<Ts, TEvent>, typename Tsm::logger_t>::execute(aux::get_by_id<Ns>(&g), event, sm, deps, subs) &&
+            ...);
+#else
+    auto result = true;
+    (void)aux::swallow{0, (result = result && call<TEvent, args_t<Ts, TEvent>, typename Tsm::logger_t>::execute(
+                                                  aux::get_by_id<Ns>(&g), event, sm, deps, subs),
+                           0)...};
+    return result;
+#endif
+  }
+  aux::tuple<Ts...> g;
+};
+template <class... Ts>
+class or_ : operator_base {
+ public:
+  constexpr explicit or_(Ts... ts) : g(ts...) {}
+  template <class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr auto operator()(const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+    return for_all(aux::make_index_sequence<sizeof...(Ts)>{}, event, sm, deps, subs);
+  }
+
+ private:
+  template <int... Ns, class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr auto for_all(const aux::index_sequence<Ns...> &, const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+#if defined(__cpp_fold_expressions)
+    return (call<TEvent, args_t<Ts, TEvent>, typename Tsm::logger_t>::execute(aux::get_by_id<Ns>(&g), event, sm, deps, subs) ||
+            ...);
+#else
+    auto result = false;
+    (void)aux::swallow{0, (result = result || call<TEvent, args_t<Ts, TEvent>, typename Tsm::logger_t>::execute(
+                                                  aux::get_by_id<Ns>(&g), event, sm, deps, subs),
+                           0)...};
+    return result;
+#endif
+  }
+  aux::tuple<Ts...> g;
+};
+template <class T>
+class not_ : operator_base {
+ public:
+  constexpr explicit not_(T t) : g(t) {}
+  template <class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr auto operator()(const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) {
+    return !call<TEvent, args_t<T, TEvent>, typename Tsm::logger_t>::execute(g, event, sm, deps, subs);
+  }
+
+ private:
+  T g;
+};
+}  // namespace front
+template <class T, __BOOST_SML_REQUIRES(concepts::callable<bool, T>::value)>
+constexpr auto operator!(const T &t) {
+  return front::not_<aux::zero_wrapper<T>>(aux::zero_wrapper<T>{t});
+}
+template <class T1, class T2, __BOOST_SML_REQUIRES(concepts::callable<bool, T1>::value &&concepts::callable<bool, T2>::value)>
+constexpr auto operator&&(const T1 &t1, const T2 &t2) {
+  return front::and_<aux::zero_wrapper<T1>, aux::zero_wrapper<T2>>(aux::zero_wrapper<T1>{t1}, aux::zero_wrapper<T2>{t2});
+}
+template <class T1, class T2, __BOOST_SML_REQUIRES(concepts::callable<bool, T1>::value &&concepts::callable<bool, T2>::value)>
+constexpr auto operator||(const T1 &t1, const T2 &t2) {
+  return front::or_<aux::zero_wrapper<T1>, aux::zero_wrapper<T2>>(aux::zero_wrapper<T1>{t1}, aux::zero_wrapper<T2>{t2});
+}
+template <class T1, class T2, __BOOST_SML_REQUIRES(concepts::callable<void, T1>::value &&concepts::callable<void, T2>::value)>
+constexpr auto operator,(const T1 &t1, const T2 &t2) {
+  return front::seq_<aux::zero_wrapper<T1>, aux::zero_wrapper<T2>>(aux::zero_wrapper<T1>{t1}, aux::zero_wrapper<T2>{t2});
+}
+namespace front {
+namespace actions {
+struct defer : action_base {
+  template <class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr void operator()(const TEvent &event, Tsm &sm, TDeps &, TSubs &) {
+    if (sm.defer_processing_) {
+      sm.defer_again_ = true;
+    } else {
+      sm.defer_.push_back(event);
+    }
+  }
+};
+}  // namespace actions
+}  // namespace front
+using testing = back::policies::testing;
+template <class T>
+using logger = back::policies::logger<T>;
+template <class T>
+using thread_safe = back::policies::thread_safe<T>;
+template <class T>
+using dispatch = back::policies::dispatch<T>;
+template <template <class...> class T>
+using defer_queue = back::policies::defer_queue<T>;
+template <template <class...> class T>
+using process_queue = back::policies::process_queue<T>;
+using dont_instantiate_statemachine_class = back::policies::dont_instantiate_statemachine_class;
+#if defined(_MSC_VER) && !defined(__clang__)
+template <class T, class... TPolicies, class T__ = aux::remove_reference_t<decltype(aux::declval<T>())>>
+using sm = back::sm<back::sm_policy<T__, TPolicies...>>;
+#else
+template <class T, class... TPolicies>
+using sm = back::sm<back::sm_policy<T, TPolicies...>>;
+#endif
+#if defined(__cpp_deduction_guides)
+namespace front {
+template <class T, class... TPolicies>
+struct sm : back::sm<back::sm_policy<T, TPolicies...>> {
+  constexpr sm(T t) : back::sm<back::sm_policy<T, TPolicies...>>::sm{t} {}
+  using back::sm<back::sm_policy<T, TPolicies...>>::sm;
+};
+}  // namespace front
+#endif
+namespace concepts {
+aux::false_type transitional_impl(...);
+template <class T>
+auto transitional_impl(T &&t) -> aux::always<typename T::dst_state, typename T::src_state, typename T::event, typename T::deps,
+                                             decltype(T::initial), decltype(T::history)>;
+template <class T>
+struct transitional : decltype(transitional_impl(aux::declval<T>())) {};
+}  // namespace concepts
+namespace front {
+namespace actions {
+struct process {
+  template <class TEvent>
+  class process_impl : public action_base {
+   public:
+    constexpr explicit process_impl(const TEvent &event) : event(event) {}
+    template <class T, class Tsm, class TDeps, class TSubs>
+    constexpr void operator()(const T &, Tsm &, TDeps &, TSubs &subs) {
+      aux::get<get_root_sm_t<TSubs>>(subs).process_.push(event);
+    }
+
+   private:
+    TEvent event{};
+  };
+  template <class TEvent>
+  constexpr auto operator()(const TEvent &event) {
+    return process_impl<TEvent>{event};
+  }
+};
+}  // namespace actions
+}  // namespace front
+namespace front {
+template <class, class>
+struct transition_eg;
+template <class, class>
+struct transition_ea;
+template <class TEvent>
+struct event {
+  template <class T, __BOOST_SML_REQUIRES(concepts::callable<bool, T>::value)>
+  constexpr auto operator[](const T &t) const {
+    return transition_eg<event, aux::zero_wrapper<T>>{*this, aux::zero_wrapper<T>{t}};
+  }
+  template <class T, __BOOST_SML_REQUIRES(concepts::callable<void, T>::value)>
+  constexpr auto operator/(const T &t) const {
+    return transition_ea<event, aux::zero_wrapper<T>>{*this, aux::zero_wrapper<T>{t}};
+  }
+  constexpr auto operator()() const { return TEvent{}; }
+};
+}  // namespace front
+namespace front {
+struct initial_state {};
+struct history_state {};
+template <class...>
+struct transition;
+template <class, class>
+struct transition_sa;
+template <class, class>
+struct transition_sg;
+template <class, class>
+struct transition_eg;
+template <class>
+struct state;
+template <class TState>
+struct state_impl {
+  template <class T>
+  constexpr auto operator<=(const T &t) const {
+    return transition<TState, T>{static_cast<const TState &>(*this), t};
+  }
+  template <class T>
+  constexpr auto operator+(const T &t) const {
+    return transition<TState, T>{static_cast<const TState &>(*this), t};
+  }
+  template <class T, __BOOST_SML_REQUIRES(concepts::callable<bool, T>::value)>
+  constexpr auto operator[](const T &t) const {
+    return transition_sg<TState, aux::zero_wrapper<T>>{static_cast<const TState &>(*this), aux::zero_wrapper<T>{t}};
+  }
+  template <class T, __BOOST_SML_REQUIRES(concepts::callable<void, T>::value)>
+  constexpr auto operator/(const T &t) const {
+    return transition_sa<TState, aux::zero_wrapper<T>>{static_cast<const TState &>(*this), aux::zero_wrapper<T>{t}};
+  }
+};
+template <class TState>
+struct state : state_impl<state<TState>> {
+  using type = TState;
+  static constexpr auto initial = false;
+  static constexpr auto history = false;
+  constexpr auto operator*() const { return state<TState(initial_state)>{}; }
+  constexpr auto operator()(const initial_state &) const { return state<TState(initial_state)>{}; }
+  constexpr auto operator()(const history_state &) const { return state<TState(history_state)>{}; }
+  template <class... Ts>
+  constexpr auto operator()(const state<Ts> &...) const {
+    return state<TState(Ts...)>{};
+  }
+  template <class T>
+  constexpr auto operator=(const T &t) const {
+    return transition<T, state>{t, *this};
+  }
+  template <class T>
+  constexpr auto sm() const {
+    return state<back::sm<back::sm_policy<T, aux::identity<TState>>>>{};
+  }
+};
+template <class TState>
+struct state<TState(initial_state)> : state_impl<state<TState(initial_state)>> {
+  using type = TState;
+  static constexpr auto initial = true;
+  static constexpr auto history = false;
+  template <class T>
+  constexpr auto operator=(const T &t) const {
+    return transition<T, state>{t, *this};
+  }
+};
+template <class TState>
+struct state<TState(history_state)> : state_impl<state<TState(history_state)>> {
+  using type = TState;
+  static constexpr auto initial = true;
+  static constexpr auto history = true;
+  template <class T>
+  constexpr auto operator=(const T &t) const {
+    return transition<T, state>{t, *this};
+  }
+};
+#if defined(_MSC_VER) && !defined(__clang__)
+template <class T, class T__ = aux::remove_reference_t<decltype(aux::declval<T>())>, class = void>
+struct state_sm {
+  using type = state<T>;
+};
+template <class T, class T__>
+struct state_sm<T, T__, aux::enable_if_t<concepts::composable<T__>::value>> {
+  using type = state<back::sm<back::sm_policy<T__>>>;
+};
+#else
+template <class T, class = void>
+struct state_sm {
+  using type = state<T>;
+};
+template <class T>
+struct state_sm<T, aux::enable_if_t<concepts::composable<T>::value>> {
+  using type = state<back::sm<back::sm_policy<T>>>;
+};
+#endif
+}  // namespace front
+namespace front {
+struct internal {};
+template <class, class>
+struct ignore;
+template <class E, class... Ts>
+struct ignore<E, aux::type_list<Ts...>> {
+  template <class T>
+  struct non_events {
+    using type =
+        aux::conditional_t<aux::is_same<back::get_event_t<E>, aux::remove_const_t<aux::remove_reference_t<T>>>::value ||
+                               aux::is_same<T, action_base>::value,
+                           aux::type_list<>, aux::type_list<T>>;
+  };
+  using type = aux::join_t<typename non_events<Ts>::type...>;
+};
+template <class T, class E, class = void>
+struct get_deps {
+  using type = typename ignore<E, args_t<T, E>>::type;
+};
+template <class T, class E>
+using get_deps_t = typename get_deps<T, E>::type;
+template <template <class...> class T, class... Ts, class E>
+struct get_deps<T<Ts...>, E, aux::enable_if_t<aux::is_base_of<operator_base, T<Ts...>>::value>> {
+  using type = aux::join_t<get_deps_t<Ts, E>...>;
+};
+struct always {
+  using type = always;
+  constexpr bool operator()() const { return true; }
+  __BOOST_SML_ZERO_SIZE_ARRAY(aux::byte);
+};
+struct none {
+  using type = none;
+  constexpr void operator()() {}
+  __BOOST_SML_ZERO_SIZE_ARRAY(aux::byte);
+};
+template <class...>
+struct transition;
+template <class E, class G>
+struct transition<front::event<E>, G> {
+  template <class T>
+  constexpr auto operator/(const T &t) const {
+    return transition<front::event<E>, G, aux::zero_wrapper<T>>{e, g, aux::zero_wrapper<T>{t}};
+  }
+  front::event<E> e;
+  G g;
+};
+template <class E, class G, class A>
+struct transition<front::event<E>, G, A> {
+  front::event<E> e;
+  G g;
+  A a;
+};
+template <class S2, class G, class A>
+struct transition<state<S2>, G, A> : transition<state<internal>, state<S2>, front::event<back::anonymous>, G, A> {
+  using transition<state<internal>, state<S2>, front::event<back::anonymous>, G, A>::g;
+  using transition<state<internal>, state<S2>, front::event<back::anonymous>, G, A>::a;
+  constexpr transition(const G &g, const A &a) : transition<state<internal>, state<S2>, front::event<back::anonymous>, G, A>{g, a} {}
+  template <class T>
+  constexpr auto operator=(const T &) const {
+    return transition<T, state<S2>, front::event<back::anonymous>, G, A>{g, a};
+  }
+  const auto &operator()() const { return *this; }
+  template <class TEvent, class Tsm, class TDeps, class TSubs>
+  constexpr auto operator()(const TEvent &event, Tsm &sm, TDeps &deps, TSubs &subs) -> void {
+    typename Tsm::state_t s{};
+    this->execute(event, sm, deps, subs, s);
+  }
+};
+template <class S1, class S2>
+struct transition<state<S1>, state<S2>> : transition<state<S1>, state<S2>, front::event<back::anonymous>, always, none> {
+  constexpr transition(const state<S1> &, const state<S2> &)
+      : transition<state<S1>, state<S2>, front::event<back::anonymous>, always, none>{always{}, none{}} {}
+};
+template <class S2, class G>
+struct transition_sg<state<S2>, G> : transition<state<internal>, state<S2>, front::event<back::anonymous>, G, none> {
+  using transition<state<internal>, state<S2>, front::event<back::anonymous>, G, none>::g;
+  transition_sg(const state<S2> &, const G &g)
+      : transition<state<internal>, state<S2>, front::event<back::anonymous>, G, none>{g, none{}} {}
+  template <class T>
+  constexpr auto operator/(const T &t) const {
+    return transition<state<S2>, G, aux::zero_wrapper<T>>{g, aux::zero_wrapper<T>{t}};
+  }
+  template <class T>
+  constexpr auto operator=(const T &) const {
+    return transition<T, state<S2>, front::event<back::anonymous>, G, none>{g, none{}};
+  }
+};
+template <class S2, class A>
+struct transition_sa<state<S2>, A> : transition<state<internal>, state<S2>, front::event<back::anonymous>, always, A> {
+  using transition<state<internal>, state<S2>, front::event<back::anonymous>, always, A>::a;
+  transition_sa(const state<S2> &, const A &a)
+      : transition<state<internal>, state<S2>, front::event<back::anonymous>, always, A>{always{}, a} {}
+  template <class T>
+  constexpr auto operator=(const T &) const {
+    return transition<T, state<S2>, front::event<back::anonymous>, always, A>{always{}, a};
+  }
+};
+template <class S2, class E>
+struct transition<state<S2>, front::event<E>> {
+  template <class T>
+  constexpr auto operator=(const T &) const {
+    return transition<T, state<S2>, front::event<E>, always, none>{always{}, none{}};
+  }
+  const state<S2> &s2;
+  front::event<E> e;
+};
+template <class E, class G>
+struct transition_eg<front::event<E>, G> {
+  template <class T>
+  constexpr auto operator/(const T &t) const {
+    return transition<front::event<E>, G, aux::zero_wrapper<T>>{e, g, aux::zero_wrapper<T>{t}};
+  }
+  front::event<E> e;
+  G g;
+};
+template <class E, class A>
+struct transition_ea<front::event<E>, A> {
+  front::event<E> e;
+  A a;
+};
+template <class S1, class S2, class G, class A>
+struct transition<state<S1>, transition<state<S2>, G, A>>
+    : transition<state<S1>, state<S2>, front::event<back::anonymous>, G, A> {
+  constexpr transition(const state<S1> &, const transition<state<S2>, G, A> &t)
+      : transition<state<S1>, state<S2>, front::event<back::anonymous>, G, A>{t.g, t.a} {}
+};
+template <class S1, class E, class G, class A>
+struct transition<state<S1>, transition<front::event<E>, G, A>>
+    : transition<state<internal>, state<S1>, front::event<E>, G, A> {
+  using transition<state<internal>, state<S1>, front::event<E>, G, A>::g;
+  using transition<state<internal>, state<S1>, front::event<E>, G, A>::a;
+  constexpr transition(const state<S1> &, const transition<front::event<E>, G, A> &t)
+      : transition<state<internal>, state<S1>, front::event<E>, G, A>{t.g, t.a} {}
+  template <class T>
+  constexpr auto operator=(const T &) const {
+    return transition<T, state<S1>, front::event<E>, G, A>{g, a};
+  }
+};
+template <class S1, class S2, class E>
+struct transition<state<S1>, transition<state<S2>, front::event<E>>>
+    : transition<state<S1>, state<S2>, front::event<E>, always, none> {
+  constexpr transition(const state<S1> &, const transition<state<S2>, front::event<E>> &)
+      : transition<state<S1>, state<S2>, front::event<E>, always, none>{always{}, none{}} {}
+};
+template <class S1, class S2, class G>
+struct transition<state<S1>, transition_sg<state<S2>, G>>
+    : transition<state<S1>, state<S2>, front::event<back::anonymous>, G, none> {
+  constexpr transition(const state<S1> &, const transition_sg<state<S2>, G> &t)
+      : transition<state<S1>, state<S2>, front::event<back::anonymous>, G, none>{t.g, none{}} {}
+};
+template <class S1, class S2, class A>
+struct transition<state<S1>, transition_sa<state<S2>, A>>
+    : transition<state<S1>, state<S2>, front::event<back::anonymous>, always, A> {
+  constexpr transition(const state<S1> &, const transition_sa<state<S2>, A> &t)
+      : transition<state<S1>, state<S2>, front::event<back::anonymous>, always, A>{always{}, t.a} {}
+};
+template <class S2, class E, class G>
+struct transition<state<S2>, transition_eg<front::event<E>, G>>
+    : transition<state<internal>, state<S2>, front::event<E>, G, none> {
+  using transition<state<internal>, state<S2>, front::event<E>, G, none>::g;
+  constexpr transition(const state<S2> &, const transition_eg<front::event<E>, G> &t)
+      : transition<state<internal>, state<S2>, front::event<E>, G, none>{t.g, none{}} {}
+  template <class T>
+  constexpr auto operator=(const T &) const {
+    return transition<T, state<S2>, front::event<E>, G, none>{g, none{}};
+  }
+};
+template <class S1, class S2, class E, class G>
+struct transition<state<S1>, transition<state<S2>, transition_eg<front::event<E>, G>>>
+    : transition<state<S1>, state<S2>, front::event<E>, G, none> {
+  constexpr transition(const state<S1> &, const transition<state<S2>, transition_eg<front::event<E>, G>> &t)
+      : transition<state<S1>, state<S2>, front::event<E>, G, none>{t.g, none{}} {}
+};
+template <class S2, class E, class A>
+struct transition<state<S2>, transition_ea<front::event<E>, A>>
+    : transition<state<internal>, state<S2>, front::event<E>, always, A> {
+  using transition<state<internal>, state<S2>, front::event<E>, always, A>::a;
+  constexpr transition(const state<S2> &, const transition_ea<front::event<E>, A> &t)
+      : transition<state<internal>, state<S2>, front::event<E>, always, A>{always{}, t.a} {}
+  template <class T>
+  constexpr auto operator=(const T &) const {
+    return transition<T, state<S2>, front::event<E>, always, A>{always{}, a};
+  }
+};
+template <class S1, class S2, class E, class A>
+struct transition<state<S1>, transition<state<S2>, transition_ea<front::event<E>, A>>>
+    : transition<state<S1>, state<S2>, front::event<E>, always, A> {
+  constexpr transition(const state<S1> &, const transition<state<S2>, transition_ea<front::event<E>, A>> &t)
+      : transition<state<S1>, state<S2>, front::event<E>, always, A>{always{}, t.a} {}
+};
+template <class S1, class S2, class E, class G, class A>
+struct transition<state<S1>, transition<state<S2>, transition<front::event<E>, G, A>>>
+    : transition<state<S1>, state<S2>, front::event<E>, G, A> {
+  constexpr transition(const state<S1> &, const transition<state<S2>, transition<front::event<E>, G, A>> &t)
+      : transition<state<S1>, state<S2>, front::event<E>, G, A>{t.g, t.a} {}
+};
+template <class T, class TSubs, class... Ts, class... THs>
+constexpr void update_composite_states(TSubs &subs, aux::true_type, const aux::type_list<THs...> &) {
+  using state_t = typename T::state_t;
+  auto &sm = back::sub_sm<T>::get(&subs);
+  (void)sm;
+#if defined(__cpp_fold_expressions)
+  ((sm.current_state_[aux::get_id<state_t, THs>((typename T::initial_states_ids_t *)0)] =
+        aux::get_id<state_t, THs>((typename T::states_ids_t *)0)),
+   ...);
+#else
+  (void)aux::swallow{0, (sm.current_state_[aux::get_id<state_t, THs>((typename T::initial_states_ids_t *)0)] =
+                             aux::get_id<state_t, THs>((typename T::states_ids_t *)0),
+                         0)...};
+#endif
+}
+template <class T, class TSubs, class... Ts>
+constexpr void update_composite_states(TSubs &subs, aux::false_type, Ts &&...) {
+  back::sub_sm<T>::get(&subs).initialize(typename T::initial_states_t{});
+}
+template <class SM, class TDeps, class TSubs, class TSrcState, class TDstState>
+constexpr void update_current_state(SM &, TDeps &deps, TSubs &, typename SM::state_t &current_state,
+                          const typename SM::state_t &new_state, const TSrcState &, const TDstState &) {
+  back::policies::log_state_change<typename SM::sm_t>(aux::type<typename SM::logger_t>{}, deps,
+                                                      aux::string<typename TSrcState::type>{},
+                                                      aux::string<typename TDstState::type>{});
+  current_state = new_state;
+}
+template <class SM, class TDeps, class TSubs, class TSrcState, class T>
+constexpr void update_current_state(SM &, TDeps &deps, TSubs &subs, typename SM::state_t &current_state,
+                          const typename SM::state_t &new_state, const TSrcState &, const state<back::sm<T>> &) {
+  back::policies::log_state_change<typename SM::sm_t>(aux::type<typename SM::logger_t>{}, deps,
+                                                      aux::string<typename TSrcState::type>{}, aux::string<T>{});
+  current_state = new_state;
+  update_composite_states<back::sm_impl<T>>(subs, typename back::sm_impl<T>::has_history_states{},
+                                            typename back::sm_impl<T>::history_states_t{});
+}
+template <class S1, class S2, class E, class G, class A>
+struct transition<state<S1>, state<S2>, front::event<E>, G, A> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = typename state<S1>::type;
+  using event = E;
+  using guard = G;
+  using action = A;
+  using deps = aux::apply_t<aux::unique_t, aux::join_t<get_deps_t<G, E>, get_deps_t<A, E>>>;
+  constexpr transition(const G &g, const A &a) : g(g), a(a) {}
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::true_type) {
+    if (call<TEvent, args_t<G, TEvent>, typename SM::logger_t>::execute(g, event, sm, deps, subs)) {
+      sm.process_internal_event(back::on_exit<back::_, TEvent>{event}, deps, subs, current_state);
+      update_current_state(sm, deps, subs, current_state,
+                           aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                           state<dst_state>{});
+      call<TEvent, args_t<A, TEvent>, typename SM::logger_t>::execute(a, event, sm, deps, subs);
+      sm.process_internal_event(back::on_entry<back::_, TEvent>{event}, deps, subs, current_state);
+      return true;
+    }
+    return false;
+  }
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::false_type) {
+    if (call<TEvent, args_t<G, TEvent>, typename SM::logger_t>::execute(g, event, sm, deps, subs)) {
+      update_current_state(sm, deps, subs, current_state,
+                           aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                           state<dst_state>{});
+      call<TEvent, args_t<A, TEvent>, typename SM::logger_t>::execute(a, event, sm, deps, subs);
+      return true;
+    }
+    return false;
+  }
+  G g;
+  A a;
+};
+template <class S2, class E, class G, class A>
+struct transition<state<internal>, state<S2>, front::event<E>, G, A> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = internal;
+  using event = E;
+  using guard = G;
+  using action = A;
+  using deps = aux::apply_t<aux::unique_t, aux::join_t<get_deps_t<G, E>, get_deps_t<A, E>>>;
+  constexpr transition(const G &g, const A &a) : g(g), a(a) {}
+  template <class TEvent, class SM, class TDeps, class TSubs, class... Ts>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &, Ts &&...) {
+    if (call<TEvent, args_t<G, TEvent>, typename SM::logger_t>::execute(g, event, sm, deps, subs)) {
+      call<TEvent, args_t<A, TEvent>, typename SM::logger_t>::execute(a, event, sm, deps, subs);
+      return true;
+    }
+    return false;
+  }
+  G g;
+  A a;
+};
+template <class S1, class S2, class E, class A>
+struct transition<state<S1>, state<S2>, front::event<E>, always, A> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = typename state<S1>::type;
+  using event = E;
+  using guard = always;
+  using action = A;
+  using deps = aux::apply_t<aux::unique_t, get_deps_t<A, E>>;
+  constexpr transition(const always &, const A &a) : a(a) {}
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::true_type) {
+    sm.process_internal_event(back::on_exit<back::_, TEvent>{event}, deps, subs, current_state);
+    update_current_state(sm, deps, subs, current_state,
+                         aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                         state<dst_state>{});
+    call<TEvent, args_t<A, TEvent>, typename SM::logger_t>::execute(a, event, sm, deps, subs);
+    sm.process_internal_event(back::on_entry<back::_, TEvent>{event}, deps, subs, current_state);
+    return true;
+  }
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::false_type) {
+    update_current_state(sm, deps, subs, current_state,
+                         aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                         state<dst_state>{});
+    call<TEvent, args_t<A, TEvent>, typename SM::logger_t>::execute(a, event, sm, deps, subs);
+    return true;
+  }
+  A a;
+};
+template <class S2, class E, class A>
+struct transition<state<internal>, state<S2>, front::event<E>, always, A> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = internal;
+  using event = E;
+  using guard = always;
+  using action = A;
+  using deps = aux::apply_t<aux::unique_t, get_deps_t<A, E>>;
+  constexpr transition(const always &, const A &a) : a(a) {}
+  template <class TEvent, class SM, class TDeps, class TSubs, class... Ts>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &, Ts &&...) {
+    call<TEvent, args_t<A, TEvent>, typename SM::logger_t>::execute(a, event, sm, deps, subs);
+    return true;
+  }
+  A a;
+};
+template <class S1, class S2, class E, class G>
+struct transition<state<S1>, state<S2>, front::event<E>, G, none> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = typename state<S1>::type;
+  using event = E;
+  using guard = G;
+  using action = none;
+  using deps = aux::apply_t<aux::unique_t, get_deps_t<G, E>>;
+  constexpr transition(const G &g, const none &) : g(g) {}
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::true_type) {
+    if (call<TEvent, args_t<G, TEvent>, typename SM::logger_t>::execute(g, event, sm, deps, subs)) {
+      sm.process_internal_event(back::on_exit<back::_, TEvent>{event}, deps, subs, current_state);
+      update_current_state(sm, deps, subs, current_state,
+                           aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                           state<dst_state>{});
+      sm.process_internal_event(back::on_entry<back::_, TEvent>{event}, deps, subs, current_state);
+      return true;
+    }
+    return false;
+  }
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::false_type) {
+    if (call<TEvent, args_t<G, TEvent>, typename SM::logger_t>::execute(g, event, sm, deps, subs)) {
+      update_current_state(sm, deps, subs, current_state,
+                           aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                           state<dst_state>{});
+      return true;
+    }
+    return false;
+  }
+  G g;
+};
+template <class S2, class E, class G>
+struct transition<state<internal>, state<S2>, front::event<E>, G, none> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = internal;
+  using event = E;
+  using guard = G;
+  using action = none;
+  using deps = aux::apply_t<aux::unique_t, get_deps_t<G, E>>;
+  constexpr transition(const G &g, const none &) : g(g) {}
+  template <class TEvent, class SM, class TDeps, class TSubs, class... Ts>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &, Ts &&...) {
+    return call<TEvent, args_t<G, TEvent>, typename SM::logger_t>::execute(g, event, sm, deps, subs);
+  }
+  G g;
+};
+template <class S1, class S2, class E>
+struct transition<state<S1>, state<S2>, front::event<E>, always, none> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = typename state<S1>::type;
+  using event = E;
+  using guard = always;
+  using action = none;
+  using deps = aux::type_list<>;
+  constexpr transition(const always &, const none &) {}
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &event, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::true_type) {
+    sm.process_internal_event(back::on_exit<back::_, TEvent>{event}, deps, subs, current_state);
+    update_current_state(sm, deps, subs, current_state,
+                         aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                         state<dst_state>{});
+    sm.process_internal_event(back::on_entry<back::_, TEvent>{event}, deps, subs, current_state);
+    return true;
+  }
+  template <class TEvent, class SM, class TDeps, class TSubs>
+  constexpr bool execute(const TEvent &, SM &sm, TDeps &deps, TSubs &subs, typename SM::state_t &current_state, aux::false_type) {
+    update_current_state(sm, deps, subs, current_state,
+                         aux::get_id<typename SM::state_t, dst_state>((typename SM::states_ids_t *)0), state<src_state>{},
+                         state<dst_state>{});
+    return true;
+  }
+  __BOOST_SML_ZERO_SIZE_ARRAY(aux::byte);
+};
+template <class S2, class E>
+struct transition<state<internal>, state<S2>, front::event<E>, always, none> {
+  static constexpr auto initial = state<S2>::initial;
+  static constexpr auto history = state<S2>::history;
+  using src_state = typename state<S2>::type;
+  using dst_state = internal;
+  using event = E;
+  using guard = always;
+  using action = none;
+  using deps = aux::type_list<>;
+  constexpr transition(const always &, const none &) {}
+  template <class TEvent, class SM, class TDeps, class TSubs, class... Ts>
+  constexpr bool execute(const TEvent &, SM &, TDeps &, TSubs &, typename SM::state_t &, Ts &&...) {
+    return true;
+  }
+  __BOOST_SML_ZERO_SIZE_ARRAY(aux::byte);
+};
+}  // namespace front
+using _ = back::_;
+#if !(defined(_MSC_VER) && !defined(__clang__))
+template <class TEvent>
+constexpr front::event<TEvent> event{};
+#else
+template <class TEvent>
+front::event<TEvent> event __BOOST_SML_VT_INIT;
+#endif
+template <class TEvent>
+__BOOST_SML_UNUSED front::event<back::on_entry<_, TEvent>> on_entry __BOOST_SML_VT_INIT;
+template <class TEvent>
+__BOOST_SML_UNUSED front::event<back::on_exit<_, TEvent>> on_exit __BOOST_SML_VT_INIT;
+template <class TEvent>
+front::event<back::unexpected_event<TEvent>> unexpected_event __BOOST_SML_VT_INIT;
+template <class T>
+front::event<back::exception<T>> exception __BOOST_SML_VT_INIT;
+using anonymous = back::anonymous;
+using initial = back::initial;
+#if !(defined(_MSC_VER) && !defined(__clang__))
+template <class T>
+constexpr typename front::state_sm<T>::type state{};
+#else
+template <class T>
+typename front::state_sm<T>::type state __BOOST_SML_VT_INIT;
+#endif
+#if !(defined(__ICCARM__))
+inline namespace literals {
+#if defined(__cpp_nontype_template_parameter_class) || \
+    defined(__cpp_nontype_template_args) && __cpp_nontype_template_args >= 201911L
+template <aux::fixed_string Str>
+constexpr auto operator""_s() {
+  return []<auto... Ns>(aux::index_sequence<Ns...>) { return front::state<aux::string<char, Str.data[Ns]...>>{}; }
+  (aux::make_index_sequence<Str.size>{});
+}
+template <aux::fixed_string Str>
+constexpr auto operator""_e() {
+  return []<auto... Ns>(aux::index_sequence<Ns...>) { return event<aux::string<char, Str.data[Ns]...>>; }
+  (aux::make_index_sequence<Str.size>{});
+}
+#elif !(defined(_MSC_VER) && !defined(__clang__))
+template <class T, T... Chrs>
+constexpr auto operator""_s() {
+  return front::state<aux::string<T, Chrs...>>{};
+}
+template <class T, T... Chrs>
+constexpr auto operator""_e() {
+  return event<aux::string<T, Chrs...>>;
+}
+#endif
+}  // namespace literals
+#endif
+__BOOST_SML_UNUSED static front::state<back::terminate_state> X;
+__BOOST_SML_UNUSED static front::history_state H;
+__BOOST_SML_UNUSED static front::actions::defer defer;
+__BOOST_SML_UNUSED static front::actions::process process;
+__BOOST_SML_UNUSED static front::state<class SML_EVAL> eval;
+template <class... Ts, __BOOST_SML_REQUIRES(aux::is_same<aux::bool_list<aux::always<Ts>::value...>,
+                                                         aux::bool_list<concepts::transitional<Ts>::value...>>::value)>
+constexpr auto make_transition_table(Ts... ts) {
+  return aux::pool<Ts...>{ts...};
+}
+BOOST_SML_NAMESPACE_END
+#undef __BOOST_SML_UNUSED
+#undef __BOOST_SML_VT_INIT
+#undef __BOOST_SML_ZERO_SIZE_ARRAY
+#undef __BOOST_SML_ZERO_SIZE_ARRAY_CREATE
+#undef __BOOST_SML_TEMPLATE_KEYWORD
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#elif defined(__GNUC__)
+#if defined(__BOOST_SML_DEFINED_HAS_BUILTIN)
+#undef __has_builtin
+#endif
+#pragma GCC diagnostic pop
+#elif defined(_MSC_VER) && !defined(__clang__) && defined(__BOOST_SML_DEFINED_HAS_BUILTIN)
+#undef __has_builtin
+#undef __has_builtin__make_integer_seq
+#endif
+#endif
+#endif