moved documentation

README.md

@@ -1,3 +0,0 @@
-# cpp-templates
-
-generic actual cpp-templates

templatefsm/.gitignore

@@ -0,0 +1,74 @@
+# This file is used to ignore files which are generated
+# ----------------------------------------------------------------------------
+
+*~
+*.autosave
+*.a
+*.core
+*.moc
+*.o
+*.obj
+*.orig
+*.rej
+*.so
+*.so.*
+*_pch.h.cpp
+*_resource.rc
+*.qm
+.#*
+*.*#
+core
+!core/
+tags
+.DS_Store
+.directory
+*.debug
+Makefile*
+*.prl
+*.app
+moc_*.cpp
+ui_*.h
+qrc_*.cpp
+Thumbs.db
+*.res
+*.rc
+/.qmake.cache
+/.qmake.stash
+
+# qtcreator generated files
+*.pro.user*
+CMakeLists.txt.user*
+
+# xemacs temporary files
+*.flc
+
+# Vim temporary files
+.*.swp
+
+# Visual Studio generated files
+*.ib_pdb_index
+*.idb
+*.ilk
+*.pdb
+*.sln
+*.suo
+*.vcproj
+*vcproj.*.*.user
+*.ncb
+*.sdf
+*.opensdf
+*.vcxproj
+*vcxproj.*
+
+# MinGW generated files
+*.Debug
+*.Release
+
+# Python byte code
+*.pyc
+
+# Binaries
+# --------
+*.dll
+*.exe
+

templatefsm/fsm.h

@@ -0,0 +1,295 @@
+#pragma once
+
+#include <type_traits>
+#include <utility>
+#include <variant>
+
+/** @brief Missing transition policy. */
+enum class missing_transition_policy {
+  /** @brief Missing transition is considered required by validation. */
+  strict,
+
+  /** @brief Missing transition is allowed (event ignored). */
+  ignore
+};
+
+/** @brief Marker for undefined transition. */
+struct no_transition {};
+
+/** @brief Default guard: always allow. */
+struct always_allow {
+  template <typename TContext, typename TFrom, typename TEvent>
+  bool operator() (TContext &, const TFrom &, const TEvent &) const noexcept {
+    return true;
+  }
+};
+
+/** @brief Default action: do nothing. */
+struct do_nothing {
+  template <typename TContext, typename TFrom, typename TTo, typename TEvent>
+  void operator() (TContext &, const TFrom &, const TTo &, const TEvent &) const noexcept {
+  }
+};
+
+/**
+ * @brief Transition descriptor.
+ *
+ * @tparam TTo Destination state type.
+ * @tparam TGuard Guard functor type.
+ * @tparam TAction Action functor type.
+ */
+template <typename TTo, typename TGuard = always_allow, typename TAction = do_nothing>
+struct transition_to {
+  using to_state = TTo;
+  using guard    = TGuard;
+  using action   = TAction;
+};
+
+/**
+ * @brief Transition table mapping: specialize to define transitions.
+ * Default: no_transition.
+ */
+template <typename TFrom, typename TEvent>
+struct transition {
+  using type = no_transition;
+};
+
+/** @brief Optional mapping to names for logs. */
+template <typename T>
+struct name_of {
+  static constexpr const char *value = "?";
+};
+
+/**
+ * @brief Logger interface (default no-op).
+ *
+ * You can implement:
+ *  - ignored_transition(from, event)
+ *  - unhandled_transition(from, event)   // policy=strict but missing transition at runtime
+ *  - guard_blocked(from, event)
+ */
+struct null_logger {
+  void ignored_transition (const char *, const char *) noexcept {}
+  void unhandled_transition (const char *, const char *) noexcept {}
+  void guard_blocked (const char *, const char *) noexcept {}
+};
+
+/** @brief Hooks: state-only. */
+template <typename TState>
+struct on_exit_state {
+  template <typename TContext>
+  static void call (TContext &, const TState &) noexcept {}
+};
+
+template <typename TState>
+struct on_entry_state {
+  template <typename TContext>
+  static void call (TContext &, const TState &) noexcept {}
+};
+
+/** @brief Hooks: event-specific. */
+template <typename TState, typename TEvent>
+struct on_exit_event {
+  template <typename TContext>
+  static void call (TContext &, const TState &, const TEvent &) noexcept {}
+};
+
+template <typename TState, typename TEvent>
+struct on_entry_event {
+  template <typename TContext>
+  static void call (TContext &, const TState &, const TEvent &) noexcept {}
+};
+
+/**
+ * @brief Factory: construct destination state.
+ *
+ * IMPORTANT: Now includes TContext in template parameters to avoid templated make<TContext>().
+ *
+ * Default: To{}.
+ * Specialize state_factory<TContext, From, Event, To> as needed.
+ */
+template <typename TContext, typename TFrom, typename TEvent, typename TTo>
+struct state_factory {
+  static TTo make (TContext &, const TFrom &, const TEvent &) {
+    return TTo{};
+  }
+};
+
+/**
+ * @brief Per (State,Event) missing transition policy.
+ *
+ * Default is ignore. Mark only required pairs strict.
+ */
+template <typename TFrom, typename TEvent>
+struct missing_transition {
+  static constexpr missing_transition_policy policy = missing_transition_policy::ignore;
+};
+
+/** @brief Helper: is T one of Ts... */
+template <typename T, typename... Ts>
+struct is_one_of : std::disjunction<std::is_same<T, Ts>...> {};
+
+/** @brief Helper: transition exists? */
+template <typename TFrom, typename TEvent>
+struct has_transition
+  : std::bool_constant < !std::is_same_v<typename transition<TFrom, TEvent>::type, no_transition >> {};
+
+/** @brief Factory validation (call-form). */
+template <typename TContext, typename TFrom, typename TEvent, typename TTo, typename = void>
+struct is_factory_invocable : std::false_type {};
+
+template <typename TContext, typename TFrom, typename TEvent, typename TTo>
+struct is_factory_invocable <
+  TContext, TFrom, TEvent, TTo,
+std::void_t<decltype (state_factory<TContext, TFrom, TEvent, TTo>::make (
+                        std::declval<TContext &>(),
+                        std::declval<const TFrom &>(),
+                        std::declval<const TEvent &>())) >>
+                            : std::bool_constant<std::is_same_v<
+                            decltype (state_factory<TContext, TFrom, TEvent, TTo>::make (
+                                        std::declval<TContext &>(),
+                                        std::declval<const TFrom &>(),
+                                        std::declval<const TEvent &>())),
+                                            TTo>> {};
+
+/**
+ * @brief FSM with runtime state storage and explicit compile-time validation.
+ *
+ * dispatch():
+ *  - never static_asserts on missing transitions (avoids State×Event explosion with std::visit)
+ *  - handles missing transitions via missing_transition<State,Event>::policy (ignore/strict)
+ *
+ * validate_events<Ev...>():
+ *  - compile-time checks ONLY for pairs marked strict.
+ */
+template <typename TContext, typename TLogger, typename... TStates>
+class fsm {
+  public:
+    using state_variant = std::variant<TStates...>;
+
+    template <typename TInitial,
+              typename = std::enable_if_t<is_one_of<TInitial, TStates...>::value>>
+    explicit fsm (TContext &ctx, TInitial initial, TLogger logger = TLogger{})
+      : m_ctx (ctx)
+      , m_logger (std::move (logger))
+      , m_state (std::move (initial)) {
+      std::visit (init_entry_visitor{*this}, m_state);
+    }
+
+    template <typename TEvent>
+    bool dispatch (const TEvent &ev) {
+      dispatch_visitor<TEvent> v{*this, ev};
+      return std::visit (v, m_state);
+    }
+
+    template <typename... TEvents>
+    static constexpr void validate_events() {
+      (validate_one_event<TEvents>(), ...);
+    }
+
+    const state_variant &state() const noexcept {
+      return m_state;
+    }
+    state_variant &state() noexcept {
+      return m_state;
+    }
+
+  private:
+    template <typename TEvent>
+    struct dispatch_visitor {
+      fsm &self;
+      const TEvent &ev;
+
+      template <typename TFrom>
+      bool operator() (TFrom &from) const {
+        return self.template dispatch_from<TFrom> (from, ev);
+      }
+    };
+
+    struct init_entry_visitor {
+      fsm &self;
+      template <typename TState>
+      void operator() (TState &st) const {
+        on_entry_state<TState>::call (self.m_ctx, st);
+      }
+    };
+
+    template <typename TEvent>
+    struct entry_after_commit_visitor {
+      fsm &self;
+      const TEvent &ev;
+
+      template <typename TState>
+      void operator() (TState &st) const {
+        on_entry_state<TState>::call (self.m_ctx, st);
+        on_entry_event<TState, TEvent>::call (self.m_ctx, st, ev);
+      }
+    };
+
+    template <typename TFrom, typename TEvent>
+    bool dispatch_from (TFrom &from, const TEvent &ev) {
+      using tr = typename transition<TFrom, TEvent>::type;
+
+      if constexpr (std::is_same_v<tr, no_transition>) {
+        if constexpr (missing_transition<TFrom, TEvent>::policy == missing_transition_policy::strict)
+          m_logger.unhandled_transition (name_of<TFrom>::value, name_of<TEvent>::value);
+        else
+          m_logger.ignored_transition (name_of<TFrom>::value, name_of<TEvent>::value);
+        return false;
+      } else {
+        using to_state = typename tr::to_state;
+        using guard_t  = typename tr::guard;
+        using action_t = typename tr::action;
+
+        static_assert (is_one_of<to_state, TStates...>::value,
+                       "FSM: transition target state not in FSM state list.");
+
+        static_assert (std::is_invocable_r_v<bool, guard_t, TContext &, const TFrom &, const TEvent &>,
+                       "FSM: guard must be callable as bool(Context&, const From&, const Event&).");
+
+        static_assert (std::is_invocable_r_v<void, action_t, TContext &, const TFrom &, const to_state &, const TEvent &>,
+                       "FSM: action must be callable as void(Context&, const From&, const To&, const Event&).");
+
+        static_assert (is_factory_invocable<TContext, TFrom, TEvent, to_state>::value,
+                       "FSM: state_factory<Context,From,Event,To>::make must be callable as "
+                       "To make(Context&, const From&, const Event&).");
+
+        guard_t guard{};
+        if (!guard (m_ctx, from, ev)) {
+          m_logger.guard_blocked (name_of<TFrom>::value, name_of<TEvent>::value);
+          return false;
+        }
+
+        on_exit_event<TFrom, TEvent>::call (m_ctx, from, ev);
+        on_exit_state<TFrom>::call (m_ctx, from);
+
+        to_state to = state_factory<TContext, TFrom, TEvent, to_state>::make (m_ctx, from, ev);
+
+        action_t action{};
+        action (m_ctx, from, to, ev);
+
+        m_state = std::move (to);
+
+        std::visit (entry_after_commit_visitor<TEvent> {*this, ev}, m_state);
+        return true;
+      }
+    }
+
+    template <typename TEvent>
+    static constexpr void validate_one_event() {
+      (validate_pair<TStates, TEvent>(), ...);
+    }
+
+    template <typename TState, typename TEvent>
+    static constexpr void validate_pair() {
+      if constexpr (missing_transition<TState, TEvent>::policy == missing_transition_policy::strict) {
+        static_assert (has_transition<TState, TEvent>::value,
+                       "FSM validation: required (strict) transition is missing for (State, Event).");
+      }
+    }
+
+  private:
+    TContext     &m_ctx;
+    TLogger       m_logger;
+    state_variant m_state;
+};

templatefsm/main.cpp

@@ -0,0 +1,148 @@
+#include "fsm.h"
+#include <cstdint>
+
+/** States */
+struct Idle  { };
+struct Active {
+  std::uint32_t session_id = 0;
+};
+
+/** Events */
+struct EvStart {
+  std::uint32_t requested_session = 0;
+};
+struct EvStop  { };
+
+/** Context */
+struct Context {
+  std::uint32_t starts = 0;
+};
+
+/** Names (optional) */
+template <> struct name_of<Idle>    {
+  static constexpr const char *value = "Idle";
+};
+template <> struct name_of<Active>  {
+  static constexpr const char *value = "Active";
+};
+template <> struct name_of<EvStart> {
+  static constexpr const char *value = "EvStart";
+};
+template <> struct name_of<EvStop>  {
+  static constexpr const char *value = "EvStop";
+};
+
+/** Logger */
+struct MyLogger {
+  void ignored_transition (const char *from_state, const char *event) noexcept {
+    (void)from_state;
+    (void)event;
+    // printf("FSM ignored: %s + %s\n", from_state, event);
+  }
+
+  void unhandled_transition (const char *from_state, const char *event) noexcept {
+    (void)from_state;
+    (void)event;
+    // printf("FSM UNHANDLED: %s + %s\n", from_state, event);
+  }
+
+  void guard_blocked (const char *from_state, const char *event) noexcept {
+    (void)from_state;
+    (void)event;
+    // printf("FSM guard blocked: %s + %s\n", from_state, event);
+  }
+};
+
+/** Guard */
+struct GuardStartAllowed {
+  bool operator() (Context &ctx, const Idle &, const EvStart &) const noexcept {
+    return ctx.starts < 10U;
+  }
+};
+
+/** Action */
+struct ActionOnStart {
+  void operator() (Context &ctx, const Idle &, const Active &, const EvStart &) const noexcept {
+    ++ctx.starts;
+  }
+};
+
+/** Factory specialization (NOTE: now includes Context in template parameters) */
+template <>
+struct state_factory<Context, Idle, EvStart, Active> {
+  static Active make (Context &, const Idle &, const EvStart &ev) {
+    Active a{};
+    a.session_id = ev.requested_session;
+    return a;
+  }
+};
+
+/** Hooks (optional) */
+template <>
+struct on_entry_state<Active> {
+  static void call (Context &, const Active &) noexcept {
+    // start timers, etc.
+  }
+};
+
+template <>
+struct on_exit_state<Active> {
+  static void call (Context &, const Active &) noexcept {
+    // stop timers, etc.
+  }
+};
+
+template <>
+struct on_entry_event<Active, EvStart> {
+  static void call (Context &, const Active &, const EvStart &) noexcept {
+    // entered Active due to EvStart
+  }
+};
+
+/** Transitions */
+template <>
+struct transition<Idle, EvStart> {
+  using type = transition_to<Active, GuardStartAllowed, ActionOnStart>;
+};
+
+template <>
+struct transition<Active, EvStop> {
+  using type = transition_to<Idle>;
+};
+
+/**
+ * "Adult strictness": mark only required pairs strict.
+ * Everything else is ignore by default.
+ */
+template <>
+struct missing_transition<Idle, EvStart> {
+  static constexpr missing_transition_policy policy = missing_transition_policy::strict;
+};
+
+template <>
+struct missing_transition<Active, EvStop> {
+  static constexpr missing_transition_policy policy = missing_transition_policy::strict;
+};
+
+/** FSM type */
+using MyFsm = fsm<Context, MyLogger, Idle, Active>;
+
+static constexpr void validate_fsm_contract() {
+  MyFsm::validate_events<EvStart, EvStop>();
+}
+
+int main() {
+  validate_fsm_contract();
+
+  Context ctx{};
+  MyFsm f (ctx, Idle{}, MyLogger{});
+
+  f.dispatch (EvStart{42}); // Idle -> Active
+  f.dispatch (EvStop{});   // Active -> Idle
+
+  // Not required by strict contract => default ignore (logged via ignored_transition)
+  f.dispatch (EvStop{});   // Idle + EvStop => ignored
+  f.dispatch (EvStart{7}); // (if currently Active) Active + EvStart => ignored
+
+  return 0;
+}

templatefsm/templatefsm.pro

@@ -0,0 +1,10 @@
+TEMPLATE = app
+CONFIG += console c++17
+CONFIG -= app_bundle
+CONFIG -= qt
+
+SOURCES += \
+        main.cpp
+
+HEADERS += \
+  fsm.h

typefactory/README.md

@@ -0,0 +1,190 @@
+# TypeFactory
+
+A lightweight registry-based factory for creating objects by runtime identifier.
+
+`TypeFactory` is a small header-only C++ utility for situations where the exact object type
+must be selected dynamically at runtime using an ID.
+
+Typical use cases include:
+
+- protocol command dispatch
+- vehicle type identification
+- runtime parser or handler selection
+- plugin-like object creation
+- configuration-based object instantiation
+
+The implementation is intentionally simple and follows the KISS principle.
+
+## Features
+
+- header-only implementation
+- C++17 compatible
+- compile-time validation of registered types
+- fast lookup using `std::unordered_map`
+- optional access to creator function for advanced use
+- predictable and compact API
+- suitable for both commercial and open-source projects
+
+## Requirements
+
+- C++17 or newer
+- `ClassId` must be hashable (`std::hash<ClassId>` must be available)
+
+## Basic Idea
+
+The factory stores a mapping:
+
+- **runtime ID** -> **creator function**
+
+A derived type is registered once, then can be created later by its ID.
+
+## Example
+
+```cpp
+#include "typefactory.h"
+#include <string>
+#include <memory>
+
+struct Base {
+    virtual ~Base() = default;
+    virtual int get() = 0;
+};
+
+struct Derived1 : Base {
+    explicit Derived1(int start) : m_start(start) {}
+    int get() override {
+        return m_start + 1;
+    }
+private:
+    int m_start = 0;
+};
+
+struct Derived2 : Base {
+    explicit Derived2(int start) : m_start(start) {}
+    int get() override {
+        return m_start + 2;
+    }
+private:
+    int m_start = 0;
+};
+
+int main() {
+    TypeFactory<std::string, Base, int> factory;
+
+    factory.registerType<Derived1>("one");
+    factory.registerType<Derived2>("two");
+
+    auto d1 = factory.create("one", 10);
+    auto d2 = factory.create("two", 10);
+
+    return d1->get() + d2->get();
+}
+```
+
+## Advanced Usage
+
+The factory also provides direct access to the creator function:
+
+```cpp
+auto fn = factory.creator("one");
+auto obj = fn(10);
+```
+
+This can be useful when integrating with dispatch tables or higher-level runtime logic.
+
+## API Overview
+
+### `registerType`
+
+Registers a derived type for a given runtime ID.
+
+```cpp
+factory.registerType<Derived>("id");
+```
+
+Compile-time checks ensure that:
+
+- `Derived` inherits from `BaseClass`
+- `Derived` is constructible from `Args...`
+
+If the same ID is registered again, the previous registration is overwritten.
+This is intentional: **last registration wins**.
+
+### `creator`
+
+Returns the creator function associated with the given ID.
+
+```cpp
+auto fn = factory.creator("id");
+```
+
+Throws `std::out_of_range` if the ID is not registered.
+
+### `create`
+
+Creates an object directly by ID.
+
+```cpp
+auto obj = factory.create("id", args...);
+```
+
+Throws `std::out_of_range` if the ID is not registered.
+
+### `contains`
+
+Checks whether an ID is registered.
+
+```cpp
+if (factory.contains("id")) {
+    // safe to create
+}
+```
+
+## Design Notes
+
+- `TypeFactory` is not thread-safe during registration.
+- Types should normally be registered during initialization.
+- Lookup and creation are lightweight and predictable.
+- The class is designed to be reusable as a low-level infrastructure utility.
+- The registry is stored in a protected `std::unordered_map`, so derived factories can extend the design if needed.
+
+## Why Not Abstract Factory?
+
+This utility is not a classic *Abstract Factory* pattern.
+
+A classic Abstract Factory typically creates **families of related objects**.
+
+`TypeFactory` is closer to a:
+
+- registry-based factory
+- type factory
+- runtime creator map
+
+It focuses on selecting one concrete type by runtime ID.
+
+## Example Use Cases
+
+### Vehicle Identification
+
+A controller returns a vehicle ID.  
+The system uses that ID to create the matching parameter or settings object.
+
+### Protocol Command Handling
+
+A command ID is received over the network.  
+The system selects and creates the correct handler object for that command.
+
+### Runtime Format Selection
+
+A parser or converter is selected dynamically depending on file type, message type, or configuration.
+
+## License
+
+This project is licensed under the MIT License.
+
+For source files, it is recommended to use SPDX headers such as:
+
+```cpp
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2025 Dim Himro
+```

typefactory/main.cpp

@@ -1,8 +1,42 @@
 #include <iostream>
+#include "typefactory.h"
+#include <string>
 
 using namespace std;
 
 int main() {
-  cout << "Hello World!" << endl;
+  cout << "Type factory simple example" << endl;
+
+  struct Base {
+    virtual ~Base() = default;
+    virtual int get() = 0;
+  };
+
+  struct Derived1 : Base {
+    explicit Derived1 (int start) : m_start (start) {}
+    int get() override {
+      return m_start + 1;
+    }
+    int m_start = 0;
+  };
+
+  struct Derived2 : Base {
+    explicit Derived2 (int start) : m_start (start) {}
+    int get() override {
+      return m_start + 2;
+    }
+    int m_start = 0;
+  };
+
+  TypeFactory<std::string, Base, int> factory;
+  factory.registerType<Derived1> ("one");
+  factory.registerType<Derived2> ("two");
+
+  auto a = factory.create ("one", 10);
+  auto b = factory.creator ("two") (10); // advanced API: get creator function
+
+  std::cout << a->get() << std::endl;
+  std::cout << b->get() << std::endl;
+
   return 0;
 }

typefactory/typefactory.h

@@ -1,119 +1,118 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2026 Dim Himro
+
 #ifndef TYPEFACTORY_H
 #define TYPEFACTORY_H
-#include <unordered_map>
+
-#include <type_traits>
 #include <memory>
+#include <type_traits>
+#include <unordered_map>
+#include <utility>   // std::move
 
 /**
  * @brief Registry-based factory for creating objects by runtime identifier.
  *
- * Allows registering derived types and instantiating them
+ * Allows registering derived types and instantiating them using a ClassId key.
- * using a ClassId key.
  *
- * @param ClassId - unique class identification class. For example string, or integer id.
+ * Notes:
- * @param BaseClass - all objects should have one base class. For example vehicle or parameter
+ * - Not thread-safe. Register types during initialization phase only.
- * @param Args - constructor arguments
+ * - Re-registering the same id overwrites the previous entry ("last wins").
+ * - ClassId must be hashable (std::hash<ClassId> specialization must exist).
+ *
+ * @tparam ClassId -Unique class identifier type (e.g. std::string, int, enum).
+ * @tparam BaseClass -Base type for all created objects.
+ * @tparam Arg - Constructor arguments forwarded to registered derived types (by value).
  *
  * Usage example:
  * @code
- * class Base {
+ * #include <string>
- *   public:
- *     virtual int get() = 0;
- * }
  *
- * class Derived1 : public Base {
+ * struct Base {
- *   public:
+ *   virtual ~Base() = default;
- *     Derived1 (int start) : m_start(start){}
+ *   virtual int get() = 0;
- *     int get() override {
+ * };
- *       return m_start + 1;
- *     }
- *   private:
- *     int m_start = 0;
- * }
  *
- * class Derived2 : public Base {
+ * struct Derived1 : Base {
- *   public:
+ *   explicit Derived1(int start) : m_start(start) {}
- *     Derived2 (int start) : m_start(start){}
+ *   int get() override { return m_start + 1; }
- *     int get() override {
+ *   int m_start = 0;
- *       return m_start + 2;
+ * };
- *     }
- *   private:
- *     int m_start = 0;
- * }
- * .
- * .
- * .
- * TypeFactory <std::string, Base, int> typefactory;
- * typefactory.registerType<Derived1>("one");
- * typefactory.registerType<Derived2>("2");
  *
- * auto d1 = typefactory.create ("one")(10);
+ * struct Derived2 : Base {
- * auto d2 = typefactory.create ("2")(10);
+ *   explicit Derived2(int start) : m_start(start) {}
+ *   int get() override { return m_start + 2; }
+ *   int m_start = 0;
+ * };
  *
- * d1->get();
+ * TypeFactory<std::string, Base, int> factory;
- * d2->get();
+ * factory.registerType<Derived1>("one");
+ * factory.registerType<Derived2>("two");
+ *
+ * auto a = factory.create("one", 10);
+ * auto b = factory.creator("two")(10); // advanced API: get creator function
+ *
+ * (void)a->get();
+ * (void)b->get();
  * @endcode
  */
-template<class ClassId, class BaseClass, class ... Args>
+template <class ClassId, class BaseClass, class... Args>
 class TypeFactory {
-  public:
+public:
-    typedef std::shared_ptr<BaseClass> BaseClass_SP;
+  using BasePtr   = std::shared_ptr<BaseClass>;
-    /**
+  using CreatorFn = BasePtr (*)(Args...);
-     * @brief typefactoryFunction - typefactory function pointer type. Generally speaking it is pointer to constructor.
-     */
-    typedef BaseClass_SP (*typefactoryFunction) (Args ...);
 
-    TypeFactory() = default;
+  TypeFactory() = default;
 
-    /**
+  /**
-     * @brief registerType - template function to register class in factory
+   * @brief Registers a Derived type under the given id.
-     * @param Derived - registering type
+   *
-     * @param id - unique class identification
+   * Requirements (checked at compile-time):
-     *
+   * - Derived must inherit from BaseClass
-     * Usage example:
+   * - Derived must be constructible from Args...
-     * @code
+   *
-     * typefactory.registerType<Derived1>("one");
+   * Re-registering the same id overwrites the previous entry ("last wins").
-     * typefactory.registerType<Derived2>("2");
+   */
-     * @endcode
+  template <class Derived>
-     */
+  void registerType(const ClassId& id) {
-    template<class Derived>
+    static_assert(std::is_base_of_v<BaseClass, Derived>,
-    void registerType (const ClassId& id) {
+                  "Derived must inherit from BaseClass");
-      /// Register Derived type by storing its constructor wrapper
+    static_assert(std::is_constructible_v<Derived, Args...>,
+                  "Derived must be constructible from Args...");
 
+    classes.insert_or_assign(id, &instantiate<Derived>);
+  }
 
-      static_assert(std::is_base_of_v<BaseClass, Derived>,
+  /**
-                      "Derived must inherit from BaseClass");
+   * @brief Returns creator function for the given id.
-        static_assert(std::is_constructible_v<Derived, Args...>,
+   * @throws std::out_of_range when id is not registered.
-                      "Derived must be constructible from Args...");
+   */
-      classes[id] = &typefactory<Derived>;
+  [[nodiscard]] CreatorFn creator(const ClassId& id) const {
-    }
+    return classes.at(id);
+  }
 
-    /**
+  /**
-     * @brief create - Returns creator function for id.
+   * @brief Creates an instance for the given id using provided arguments.
-     * @param id - unique class identification
+   * @throws std::out_of_range when id is not registered.
-     * @return shared pointer to new class.
+   */
-     * @throws std::out_of_range when id not found in map
+  [[nodiscard]] BasePtr create(const ClassId& id, Args... args) const {
-     */
+    return creator(id)(std::move(args)...);
-    typefactoryFunction create (const ClassId& id) const {
+  }
-      return classes.at (id);
-    }
-  protected:
-    /**
-     * @brief classes - Not thread-safe. Register types during initialization phase only.
-     */
-    std::unordered_map<ClassId, typefactoryFunction> classes;
 
-  private:
+  /**
-    /**
+   * @brief Checks whether an id is registered.
-     * @brief typefactory - main functionality, create registered object
+   */
-     * @param Derived - class type
+  [[nodiscard]] bool contains(const ClassId& id) const {
-     * @param args - constructor arguments
+    return classes.find(id) != classes.end();
-     * @return shared pointer to register Derived class
+  }
-     */
+
-    template<class Derived>
+protected:
-    static BaseClass_SP typefactory (Args ... args) {
+  // Protected by design: derived factories may extend/inspect the registry.
-      return std::make_shared<Derived> (args ...);
+  std::unordered_map<ClassId, CreatorFn> classes;
-    }
+
+private:
+  template <class Derived>
+  static BasePtr instantiate(Args... args) {
+    return std::make_shared<Derived>(std::move(args)...);
+  }
 };
-
 #endif // TYPEFACTORY_H