enum_definition.h

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/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2022-2025 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */
 
#pragma once
 
#include "python_common.h"
#include "pyobject_ptr.h"
#include "py_tuple.h"
#include "../num/num_traits.h"
#include "../stde/vector_map.h"
 
#include <unordered_map>
#include <optional>
 
namespace lass
{
    namespace python
    {
        /** @defgroup EnumDefinition Enum Definitions
         *  @brief Defining first-class enum types in Python from C++ enums.
         *
         *  This module provides helper macros and classes to define Python enum types that derive
         *  from `enum.Enum`, `enum.IntEnum`, `enum.StrEnum` or `enum.IntFlag`.
         * 
         *
         *  ### Python Enum Types
         * 
         *  The following Python enum types can be created:
         * 
         *  - `enum.IntEnum`: Values are integers, allows direct int conversion and comparison (recommended for most C++ enums)
         *  - `enum.StrEnum`: Values are strings, allows direct string operations 
         *  - `enum.IntFlag`: Integer flags supporting bitwise operations (`|`, `&`, `^`, `~`)
         *  - `enum.Enum`: Generic enums with custom value types (advanced use)
         *
         *
         *  ### Usage Overview
         * 
         *  To export a C++ enum to Python, you need **3 macros**:
         *  
         *  1. One `PY_SHADOW_*` macro in the header file to specialize `PyExportTraits`
         *  2. One `PY_DECLARE_*` macro in the source file to define the enum mapping
         *  3. One PY_MODULE_ENUM() or PY_CLASS_ENUM() macro to add the enum to a module or class
         * 
         *  Once defined, the enum can be used as parameters or return types in function signatures,
         *  as class members, etc. The header defining `PY_SHADOW_*` must be included in source
         *  files that export these functions to Python, or add the enum to a module or class.
         * 
         *  #### For `enum.IntEnum` (most common case):
         *  ```cpp
         *  // In header:
         *  PY_SHADOW_INT_ENUM(LASS_DLL_EXPORT, MyEnum);
         * 
         *  // In source:
         *  PY_DECLARE_INT_ENUM_EX(MyEnum)("MyEnum", "MyEnum documentation", {
         *      { "VALUE1", MyEnum::Value1 },
         *      { "VALUE2", MyEnum::Value2 },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, MyEnum);   // or PY_CLASS_ENUM(MyClass, MyEnum);
         *  ```
         * 
         *  #### For `enum.StrEnum` (string-based enums):
         *  ```cpp
         *  // In header:
         *  PY_SHADOW_STR_ENUM(LASS_DLL_EXPORT, Shape);
         * 
         *  // In source:
         *  PY_DECLARE_STR_ENUM_EX(Shape)("Shape", "Shape documentation", {
         *      { "CIRCLE", Shape::Circle, "circle" },
         *      { "SQUARE", Shape::Square, "square" },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, Shape);   // or PY_CLASS_ENUM(MyClass, Shape);
         *  ```
         * 
         *  #### For `enum.IntFlag` (bitfield enums):
         *  ```cpp
         *  // In header:
         *  PY_SHADOW_INT_FLAG(LASS_DLL_EXPORT, Breakfast);
         * 
         *  // In source:
         *  PY_DECLARE_INT_FLAG_EX(Breakfast)("Breakfast", "Breakfast documentation", FlagBoundary::Keep, {
         *      { "EGG", Breakfast::Egg },
         *      { "BACON", Breakfast::Bacon },
         *      { "ALL", Breakfast::All },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, Breakfast);   // or PY_CLASS_ENUM(MyClass, Breakfast);
         *  ```
         * 
         *  #### For `enum.Enum` (generic enums):
         *  ```cpp
         *  // In header:
         *  using WeekdayPair = std::pair<int, std::string>;
         *  PY_SHADOW_ENUM(LASS_DLL_EXPORT, Weekday, WeekdayPair)
         * 
         *  // In source:
         *  PY_DECLARE_ENUM_EX(Weekday, WeekdayPair)("Weekday", "Weekday documentation", {
         *      { "MONDAY", Weekday::Monday, std::make_pair(Weekday::Monday, "Monday") },
         *      { "TUESDAY", Weekday::Tuesday, std::make_pair(Weekday::Tuesday, "Tuesday") },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, Weekday);   // or PY_CLASS_ENUM(MyClass, Weekday);
         *  ```
         *  @ingroup Python
         */
 
        /** Defines the boundary behavior for `enum.IntFlag`-derived enums.
         *
         *  Controls how Python handles flag values that are outside the defined enumerators
         * 
         *  @note This feature requires Python 3.11 or later. On earlier versions, only `Keep` is supported.
         *
         *  @sa IntFlagDefinition
         *  @sa PY_DECLARE_INT_FLAG_EX
         *  @ingroup EnumDefinition
         */
        enum class FlagBoundary
        {
            Keep,   ///< Allow any integer value (most permissive)
            Strict, ///< Only allow exact flag combinations
            Conform, ///< Mask to defined bits only
        };
 
        namespace impl
        {
            /** Creates a basic `enum.Enum` type.
             *  @param name Python class name for the enum
             *  @param enumerators Tuple of (name, value) pairs
             *  @param kwargs Additional keyword arguments for enum constructor
             *  @return New enum type object
             *  @ingroup EnumDefinition
             */
            LASS_PYTHON_DLL TPyObjPtr makeEnumType(const char* name, TPyObjPtr&& enumerators, TPyObjPtr&& kwargs);
 
            /** Creates an `enum.IntEnum` type.
             *  @param name Python class name for the enum
             *  @param enumerators Tuple of (name, value) pairs  
             *  @param kwargs Additional keyword arguments for enum constructor
             *  @return New `enum.IntEnum` type object
             *  @ingroup EnumDefinition
             */
            LASS_PYTHON_DLL TPyObjPtr makeIntEnumType(const char* name, TPyObjPtr&& enumerators, TPyObjPtr&& kwargs);
 
            /** Creates an `enum.IntFlag` type.
             *  @param name Python class name for the flag enum
             *  @param enumerators Tuple of (name, value) pairs
             *  @param kwargs Additional keyword arguments for enum constructor  
             *  @param boundary Boundary behavior for invalid flag combinations
             *  @return New `enum.IntFlag` type object
             *  @ingroup EnumDefinition
             */
            LASS_PYTHON_DLL TPyObjPtr makeIntFlagType(const char* name, TPyObjPtr&& enumerators, TPyObjPtr&& kwargs, FlagBoundary boundary=FlagBoundary::Keep);
 
            /** Creates an `enum.StrEnum` type (or equivalent for Python < 3.11).
             *  @param name Python class name for the string enum
             *  @param enumerators Tuple of (name, value) pairs where values are strings
             *  @param kwargs Additional keyword arguments for enum constructor
             *  @return New `enum.StrEnum` type object  
             *  @ingroup EnumDefinition
             */
            LASS_PYTHON_DLL TPyObjPtr makeStrEnumType(const char* name, TPyObjPtr&& enumerators, TPyObjPtr&& kwargs);
        }
 
        /** Base class of all enum definitions.
         *
         *  If you define your own custom enum definition, you must derive from this class so that
         *  you can add your enum to a module or class with `PY_MODULE_ENUM()` or `PY_CLASS_ENUM()`.
         *
         *  This class is typically not used directly by user code. Use the provided
         *  IntEnumDefinition, StrEnumDefinition, IntFlagDefinition, or EnumDefinition
         *  template classes instead.
         *
         *  @ingroup EnumDefinition
         */
        class LASS_PYTHON_DLL EnumDefinitionBase
        {
        public:
            virtual ~EnumDefinitionBase();
 
            const char* name() const; ///< The name of the Python enum type
            const char* doc() const; ///< Optional docstring for the Python enum type
            PyObject* type() const; ///< The Python enum type object, after freezeDefinition() has been called
 
            /** Freeze the enum definition and create the Python enum type.
             *
             *  @note This method should _not_ be called directly. Instead, use `PY_MODULE_ENUM()` or 
             *        `PY_CLASS_ENUM()` to add the enum to a module or class, which will call this method
             *        at the appropriate time.
             */
            PyObject* freezeDefinition(const char* moduleName, const char* scopeName);
 
        protected:
            /** Construct enum definition with name only.
             *  @param name Python class name for the enum type (must have static storage duration)
             */
            EnumDefinitionBase(const char* name);
            
            /** Construct enum definition with name and documentation.
             *  @param name Python class name for the enum type (must have static storage duration)
             *  @param doc Optional docstring for the Python enum type (must have static storage duration, or nullptr)
             */
            EnumDefinitionBase(const char* name, const char* doc);
 
            /** Returns the value of an enum instances as a Python object
             * 
             *  If the object is not an instance of this enum type, a Python exception will be set
             *  and a null pointer will be returned.
             */
            TPyObjPtr valueObject(PyObject* obj) const;
 
        private:
            /** Creates the actual Python enum type object.
             *  Derived classes implement this to create the appropriate enum type (IntEnum, StrEnum, etc.).
             */
            virtual TPyObjPtr doFreezeDefinition(TPyObjPtr&& kwargs) = 0;
            
            /** Extracts the value from a Python object for type conversion.
             *  Derived classes can override this to customize value extraction logic.
             */
            virtual TPyObjPtr doValueObject(PyObject* obj) const;
 
            TPyObjPtr type_;
            const char* name_;
            const char* doc_;
        };
 
        /** Definition of an `enum.IntEnum`-derived enum type in Python.
         * 
         *  C++ enums exported using IntEnumDefinition will generate a new
         *  enum type derived from `enum.IntEnum`. The values of the Python enum
         *  will map directly on the C++ enum values, but then names need to
         *  be defined at export.
         *
         *  As `enum.IntEnum` is used, the Python enum instances will also be
         *  valid int instances, and int instances are accepted when converting
         *  from Python to C++.
         *
         *  Because this defines a new type, it must be added to a module or
         *  other class.
         *
         *  This class is typically not used directly. Use PY_SHADOW_INT_ENUM
         *  and PY_DECLARE_INT_ENUM_* macros instead.
         *
         *  @par Usage Example:
         *  ```cpp
         *  // In header:
         *  PY_SHADOW_INT_ENUM(LASS_DLL_EXPORT, MyEnum);
         * 
         *  // In source:
         *  PY_DECLARE_INT_ENUM_EX(MyEnum)("MyEnum", "MyEnum documentation", {
         *      { "VALUE1", MyEnum::Value1 },
         *      { "VALUE2", MyEnum::Value2 },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, MyEnum);   // or PY_CLASS_ENUM(MyClass, MyEnum);
         *  ```
         *
         *  @sa PY_SHADOW_INT_ENUM
         *  @sa PY_DECLARE_INT_ENUM_NAME
         *  @sa PY_DECLARE_INT_ENUM_NAME_DOC
         *  @sa PY_DECLARE_INT_ENUM_EX
         *  @sa PY_MODULE_ENUM
         *  @sa PY_CLASS_ENUM
         *  @ingroup EnumDefinition
         */
        template <typename EnumType>
        class IntEnumDefinition : public EnumDefinitionBase
        {
        public:
            using TEnum = EnumType;
            using TBase = typename std::underlying_type<EnumType>::type;
 
            /** Represents a single enumerator member with name and C++ enum value. */
            struct Enumerator
            {
                std::string name;  ///< Python name for the member
                TEnum enumerator;  ///< Corresponding C++ enum value
            };
 
            /** Construct with enum name only.
             *  @param name Python class name for the enum type (must have static storage duration)
             */
            IntEnumDefinition(const char* name) :
                EnumDefinitionBase(name)
            {
            }
            
            /** Construct with name and documentation.
             *  @param name Python class name for the enum type (must have static storage duration)
             *  @param doc Optional docstring for the Python enum type (must have static storage duration, or nullptr)
             */
            IntEnumDefinition(const char* name, const char* doc) :
                EnumDefinitionBase(name, doc)
            {
            }
            
            /** Construct with name and enumerators list.
             *  @param name Python class name for the enum type (must have static storage duration)
             *  @param enumerators List of name-value pairs defining the enum members
             */
            IntEnumDefinition(const char* name, std::initializer_list<Enumerator> enumerators) :
                EnumDefinitionBase(name),
                enumerators_(enumerators)
            {
            }
            
            /** Construct with name, documentation, and enumerators list.
             *  @param name Python class name for the enum type (must have static storage duration)
             *  @param doc Optional docstring for the Python enum type (must have static storage duration, or nullptr)
             *  @param enumerators List of name-value pairs defining the enum members
             */
            IntEnumDefinition(const char* name, const char* doc, std::initializer_list<Enumerator> enumerators) :
                EnumDefinitionBase(name, doc),
                enumerators_(enumerators)
            {
            }
 
            /** Add an enumerator member to the definition.
             *  @param name Python name for the enumerator member
             *  @param value C++ enum value
             */
            void addEnumerator(std::string name, TEnum value)
            {
                enumerators_.emplace_back(std::move(name), value);
            }
 
            /** Creates a Python enum instance from a C++ enum value.
             *  Converts the C++ enum to its corresponding Python enum instance.
             */
            PyObject* build(TEnum value) const
            {
                LockGIL LASS_UNUSED(lock);
                TPyObjPtr args = makeTuple(static_cast<TBase>(value));
                return PyObject_Call(type(), args.get(), nullptr);
            }
 
            /** Extracts a C++ enum value from a Python object.
             *  Accepts both enum instances and raw integers. Returns 0 on success, 1 on failure.
             */
            int get(PyObject* obj, TEnum& value) const
            {
                LockGIL LASS_UNUSED(lock);
                const TPyObjPtr o = valueObject(obj);
                if (!o)
                {
                    return 1;
                }
                TBase v;
                if (PyExportTraits<TBase>::get(o.get(), v) != 0)
                {
                    // this can only happen for IntFlag with FlagBoundary::KEEP
                    return 1;
                }
                value = static_cast<TEnum>(v);
                return 0;
            }
 
        protected:
            /** Creates an `enum.IntEnum`-derived type.
             *  Converts enumerators to Python tuple format and creates the integer enum type.
             */
            TPyObjPtr doFreezeDefinition(TPyObjPtr&& kwargs) override
            {
                const Py_ssize_t n = static_cast<Py_ssize_t>(enumerators_.size());
                TPyObjPtr pyEnumerators(PyTuple_New(n));
                if (!pyEnumerators)
                {
                    return TPyObjPtr();
                }
                for (Py_ssize_t i = 0; i < n; ++i)
                {
                    const Enumerator& enumerator = enumerators_[static_cast<size_t>(i)];
                    TPyObjPtr pyEnumerator(makeTuple(enumerator.name, static_cast<TBase>(enumerator.enumerator)));
                    if (!pyEnumerator || PyTuple_SetItem(pyEnumerators.get(), i, fromSharedPtrToNakedCast(pyEnumerator)) != 0)
                    {
                        return TPyObjPtr();
                    }
                }
 
                return this->doMakeEnumType(std::move(pyEnumerators), std::move(kwargs));
            }
 
            /** Extracts integer values from enum instances or integer objects.
             *  Handles both integer enum instances and raw Python integers.
             */
            TPyObjPtr doValueObject(PyObject* obj) const override
            {
                PyObject* type = this->type();
                if (PyObject_TypeCheck(obj, (PyTypeObject*) type))
                {
                    return TPyObjPtr(PyObject_GetAttrString(obj, "value"));
                }
 
                // try to convert it to an enum first ...
                if (!PyLong_Check(obj))
                {
                    PyErr_Format(PyExc_TypeError, "Expected %S or int, got %S", type, obj);
                    return TPyObjPtr();
                }
                TPyObjPtr o(PyObject_CallFunctionObjArgs(type, obj, nullptr));
                if (!o)
                {
                    return TPyObjPtr();
                }
                return TPyObjPtr(PyObject_GetAttrString(o.get(), "value"));
            }
 
            /** Creates the actual `enum.IntEnum` type object.
             *  Can be overridden by derived classes to create different enum types (e.g., IntFlag).
             */
            virtual TPyObjPtr doMakeEnumType(TPyObjPtr&& enumerators, TPyObjPtr&& kwargs)
            {
                return impl::makeIntEnumType(this->name(), std::move(enumerators), std::move(kwargs));
            }
 
        private:
            std::vector<Enumerator> enumerators_;
        };
 
        /** Definition of an `enum.IntFlag`-derived enum type in Python.
         * 
         *  C++ enums exported using IntFlagDefinition will generate a new
         *  enum type derived from `enum.IntFlag`. The values of the Python enum
         *  will map directly on the C++ enum values, but then names need to
         *  be defined at export.
         * 
         *  As `enum.IntFlag` is used, the Python enum instances will also be
         *  valid int instances, and int instances are accepted when converting
         *  from Python to C++. Additionally, bitwise operations are supported.
         * 
         *  Because this defines a new type, it must be added to a module or
         *  other class.
         * 
         *  This class is typically not used directly. Use PY_SHADOW_INT_FLAG
         *  and PY_DECLARE_INT_FLAG_* macros instead.
         * 
         *  @par Usage Example:
         *  ```cpp
         *  // In header:
         *  PY_SHADOW_INT_FLAG(LASS_DLL_EXPORT, Breakfast);
         * 
         *  // In source:
         *  PY_DECLARE_INT_FLAG_EX(Breakfast)("Breakfast", "Breakfast documentation", FlagBoundary::Keep, {
         *      { "EGG", Breakfast::Egg },
         *      { "BACON", Breakfast::Bacon },
         *      { "ALL", Breakfast::All },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, Breakfast);   // or PY_CLASS_ENUM(MyClass, Breakfast);
         *  ```
         * 
         *  @sa PY_SHADOW_INT_FLAG
         *  @sa PY_DECLARE_INT_FLAG_NAME
         *  @sa PY_DECLARE_INT_FLAG_NAME_DOC
         *  @sa PY_DECLARE_INT_FLAG_EX
         *  @sa PY_MODULE_ENUM
         *  @sa PY_CLASS_ENUM
         *  @sa FlagBoundary
         *  @ingroup EnumDefinition
         */
        template <typename EnumType>
        class IntFlagDefinition : public IntEnumDefinition<EnumType>
        {
        public:
            using TEnum = typename IntFlagDefinition<EnumType>::TEnum;
            using TBase = typename IntFlagDefinition<EnumType>::TBase;
            using Enumerator = typename IntEnumDefinition<EnumType>::Enumerator;
 
            /// Inherits all constructors from IntEnumDefinition
            using IntEnumDefinition<EnumType>::IntEnumDefinition;
 
            /** Construct with name, documentation, boundary behavior, and enumerators.
             *  @param name Python class name for the flag enum type (must have static storage duration)
             *  @param doc Optional docstring for the Python enum type (must have static storage duration, or nullptr)
             *  @param boundary Flag boundary behavior controlling how invalid flag combinations are handled
             *  @param enumerators List of name-value pairs defining the flag members
             *  
             *  @note The boundary parameter requires Python 3.11 or later. On earlier versions, only `Keep` is supported
             *        (which is the default if this constructor is not used).
             */
            IntFlagDefinition(const char* name, const char* doc, FlagBoundary boundary, std::initializer_list<Enumerator> enumerators) :
                IntEnumDefinition<EnumType>(name, doc, enumerators),
                boundary_(boundary)
            {
            }
 
        protected:
            /** Creates an `enum.IntFlag`-derived type with boundary behavior.
             *  Overrides the base class to create a flag enum with bitwise operations support.
             */
            TPyObjPtr doMakeEnumType(TPyObjPtr&& enumerators, TPyObjPtr&& kwargs) override
            {
                return impl::makeIntFlagType(this->name(), std::move(enumerators), std::move(kwargs), boundary_);
            }
 
        private:
            FlagBoundary boundary_ = FlagBoundary::Keep;
        };
 
        /** Definition of a general `enum.Enum`-derived enum type in Python.
         * 
         *  This creates enums with custom value types (not just integers or strings).
         *  This is the base class for StrEnumDefinition and can be used directly
         *  for advanced enum types with custom value types.
         * 
         *  This class is typically not used directly. Use PY_SHADOW_ENUM
         *  and PY_DECLARE_ENUM_* macros instead.
         * 
         *  @par Usage Example:
         *  ```cpp
         *  // In header:
         *  PY_SHADOW_ENUM(LASS_DLL_EXPORT, MyEnum, std::string);
         * 
         *  // In source:
         *  PY_DECLARE_ENUM_EX(MyEnum, std::string)("MyEnum", "MyEnum documentation", {
         *      { "VALUE1", MyEnum::Value1, "custom_value_1" },
         *      { "VALUE2", MyEnum::Value2, "custom_value_2" },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, MyEnum);   // or PY_CLASS_ENUM(MyClass, MyEnum);
         *  ```
         * 
         *  @sa PY_SHADOW_ENUM
         *  @sa PY_DECLARE_ENUM_NAME
         *  @sa PY_DECLARE_ENUM_NAME_DOC
         *  @sa PY_DECLARE_ENUM_EX
         *  @sa PY_MODULE_ENUM
         *  @sa PY_CLASS_ENUM
         *  @ingroup EnumDefinition
         */
        template <typename EnumType, typename ValueType>
        class EnumDefinition : public EnumDefinitionBase
        {
        public:
            using TEnum = EnumType;
            using TValue = ValueType;
 
            /** Represents a single enumerator with name, C++ enum value, and Python value. */
            struct Enumerator
            {
                std::string name;  ///< Python name for the enumerator
                TEnum enumerator;  ///< Corresponding C++ enum value
                TValue value;      ///< Python value for the enumerator
            };
 
            /** Construct with enum name only.
             *  @param name Python class name for the enum type (must have static storage duration)
             */
            EnumDefinition(const char* name) :
                EnumDefinitionBase(name)
            {
            }
            
            /** Construct with name and documentation.
             *  @param name Python class name for the enum type (must have static storage duration)
             *  @param doc Optional docstring for the Python enum type (must have static storage duration, or nullptr)
             */
            EnumDefinition(const char* name, const char* doc) :
                EnumDefinitionBase(name, doc)
            {
            }
            
            /** Construct with name and enumerators list.
             *  @param name Python class name for the enum type (must have static storage duration)
             *  @param enumerators List of name-enum-value triples defining the enum members
             */
            EnumDefinition(const char* name, std::initializer_list<Enumerator> enumerators) :
                EnumDefinitionBase(name),
                enumerators_(enumerators)
            {
            }
            
            /** Construct with name, documentation, and enumerators list.
             *  @param name Python class name for the enum type (must have static storage duration)
             *  @param doc Optional docstring for the Python enum type (must have static storage duration, or nullptr)
             *  @param enumerators List of name-enum-value triples defining the enum members
             */
            EnumDefinition(const char* name, const char* doc, std::initializer_list<Enumerator> enumerators) :
                EnumDefinitionBase(name, doc),
                enumerators_(enumerators)
            {
            }
 
            /** Add an enumerator to the definition.
             *  @param name Python name for the enumerator
             *  @param enumerator C++ enum value
             *  @param value Python value for the enumerator
             */
            void addEnumerator(std::string name, TEnum enumerator, TValue value)
            {
                enumerators_.emplace_back(std::move(name), enumerator, std::move(value));
            }
 
            /** Creates a Python enum instance from a C++ enum value.
             *  Looks up the Python value corresponding to the C++ enum and creates an enum instance.
             */
            PyObject* build(TEnum value) const
            {
                LockGIL LASS_UNUSED(lock);
                auto val = this->getValue(value);
                if (!val)
                {
                    PyErr_Format(PyExc_ValueError, "%lld is not a valid C++ value for %S", 
                        static_cast<PY_LONG_LONG>(value), type());
                    return nullptr;
                }
                TPyObjPtr args = makeTuple(*val);
                return PyObject_Call(type(), args.get(), nullptr);
            }
 
            /** Extracts a C++ enum value from a Python object.
             *  Accepts enum instances and compatible value types. Returns 0 on success, 1 on failure.
             */
            int get(PyObject* obj, TEnum& value) const
            {
                LockGIL LASS_UNUSED(lock);
                const TPyObjPtr o = valueObject(obj);
                if (!o)
                {
                    return 1;
                }
                TValue v;
                if (PyExportTraits<TValue>::get(o.get(), v) != 0)
                {
                    // by construction this should never happen
                    // o should always be the right type ...
                    return 1;
                }
                auto val = getEnum(v);
                if (!val)
                {
                    // this should never happen, by construction o _must_ be a valid enumerator
                    PyErr_Format(PyExc_ValueError, "%S is not a valid value for %S", o.get(), type());
                    return 1;
                }
                value = *val;
                return 0;
            }
 
            std::optional<TValue> getValue(TEnum enumerator) const
            {
                auto it = enumToValue_.find(enumerator);
                if (it == enumToValue_.end())
                {
                    return std::nullopt;
                }
                return it->second;
            }
 
            std::optional<TEnum> getEnum(const TValue& value) const
            {
                auto it = valueToEnum_.find(value);
                if (it == valueToEnum_.end())
                {
                    return std::nullopt;
                }
                return it->second;
            }
 
        protected:
            /** Converts stored enumerators to Python tuple format and builds lookup tables.
             *  Creates bidirectional mappings between C++ enum values and Python values.
             */
            TPyObjPtr freezeEnumerators()
            {
                const Py_ssize_t n = static_cast<Py_ssize_t>(enumerators_.size());
                TPyObjPtr pyEnumerators(PyTuple_New(n));
                for (Py_ssize_t i = 0; i < n; ++i)
                {
                    const Enumerator& enumerator = enumerators_[static_cast<size_t>(i)];
                    assert(!enumToValue_.contains(enumerator.enumerator));
                    enumToValue_.emplace(enumerator.enumerator, enumerator.value);
                    assert(!valueToEnum_.contains(enumerator.value));
                    valueToEnum_.emplace(enumerator.value, enumerator.enumerator);
                    TPyObjPtr pyEnumerator(makeTuple(enumerator.name, enumerator.value));
                    PyTuple_SetItem(pyEnumerators.get(), i, fromSharedPtrToNakedCast(pyEnumerator));
                }
                return pyEnumerators;
            }
 
            /** Creates a generic `enum.Enum`-derived type.
             *  Processes enumerators and creates a Python enum type with custom value types.
             */
            TPyObjPtr doFreezeDefinition(TPyObjPtr &&kwargs) override
            {
                TPyObjPtr pyEnumerators = freezeEnumerators();
                if (!pyEnumerators)
                {
                    return TPyObjPtr();
                }
                return impl::makeEnumType(this->name(), std::move(pyEnumerators), std::move(kwargs));
            }
 
        private:
            std::vector<Enumerator> enumerators_;
            stde::vector_map<TEnum, TValue> enumToValue_;
            stde::vector_map<TValue, TEnum> valueToEnum_;
        };
 
        /** Definition of an `enum.StrEnum`-derived enum type in Python.
         * 
         *  C++ enums exported using StrEnumDefinition will generate a new
         *  enum type derived from `enum.StrEnum` (or `enum.Enum` + str for Python < 3.11).
         *  The values of the Python enum will be strings, and how they map on the
         *  C++ enum values needs to be defined at export.
         * 
         *  As `enum.StrEnum` is used, the Python enum instances will also be
         *  valid str instances, and str instances are accepted when
         *  converting from Python to C++.
         * 
         *  Because this defines a new type, it must be added to a module or
         *  other class.
         * 
         *  This class is typically not used directly. Use PY_SHADOW_STR_ENUM
         *  and PY_DECLARE_STR_ENUM_* macros instead.
         * 
         *  @par Usage Example:
         *  ```cpp
         *  // In header:
         *  PY_SHADOW_STR_ENUM(LASS_DLL_EXPORT, Shape);
         * 
         *  // In source:
         *  PY_DECLARE_STR_ENUM_EX(Shape)("Shape", "Shape documentation", {
         *      { "CIRCLE", Shape::Circle, "circle" },
         *      { "SQUARE", Shape::Square, "square" },
         *  });
         * 
         *  // Add to module or class:
         *  PY_MODULE_ENUM(mymodule, Shape);   // or PY_CLASS_ENUM(MyClass, Shape);
         *  ```
         * 
         *  @sa PY_SHADOW_STR_ENUM
         *  @sa PY_DECLARE_STR_ENUM_NAME
         *  @sa PY_DECLARE_STR_ENUM_NAME_DOC
         *  @sa PY_DECLARE_STR_ENUM_EX
         *  @sa PY_MODULE_ENUM
         *  @sa PY_CLASS_ENUM
         *  @ingroup EnumDefinition
         */
        template <typename EnumType, typename ValueType=std::string>
        class StrEnumDefinition : public EnumDefinition<EnumType, ValueType>
        {
        public:
            using EnumDefinition<EnumType, ValueType>::EnumDefinition;
 
        protected:
            /** Creates an `enum.StrEnum`-derived type.
             *  Processes enumerators and creates a Python string enum type.
             */
            TPyObjPtr doFreezeDefinition(TPyObjPtr&& kwargs) override
            {
                return impl::makeStrEnumType(this->name(), this->freezeEnumerators(), std::move(kwargs));
            }
 
            /** Extracts string values from enum instances or string objects.
             *  Handles both string enum instances and raw Python strings.
             */
            TPyObjPtr doValueObject(PyObject* obj) const override
            {
                PyObject* type = this->type();
                if (PyObject_TypeCheck(obj, (PyTypeObject*) type))
                {
                    return TPyObjPtr(PyObject_GetAttrString(obj, "value"));
                }
 
                // try to convert it to an enum first ...
 
                if (!PyUnicode_Check(obj))
                {
                    PyErr_Format(PyExc_TypeError, "Expected %S or str, got %S", type, obj);
                    return TPyObjPtr();
                }
                TPyObjPtr o(PyObject_CallFunctionObjArgs(type, obj, nullptr));
                if (!o)
                {
                    return TPyObjPtr();
                }
                return TPyObjPtr(PyObject_GetAttrString(o.get(), "value"));
            }
        };
    }
}
 
 
 
/** @addtogroup EnumDefinition
 *  @name Integer Enum Support
 *  Macros for exporting C++ integer enums as Python `enum.IntEnum` types.
 *  @{
 */
 
/** Specializes PyExportTraits for a C++ enum using `enum.IntEnum`.
 *  Use this in header files, then use PY_DECLARE_INT_ENUM_* in source files.
 *  @param dllInterface Export specification (e.g., LASS_DLL_EXPORT)
 *  @param t_cppEnum C++ enum type
 *  @sa lass::python::IntEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_SHADOW_INT_ENUM(dllInterface, t_cppEnum)\
    namespace lass \
    { \
    namespace python \
    { \
        template <> \
        struct PyExportTraits<t_cppEnum> \
        { \
            using TEnum = t_cppEnum; \
            using TEnumDefinition = IntEnumDefinition<TEnum>; \
            static dllInterface TEnumDefinition enumDefinition; \
            static PyObject* build(TEnum value) { return enumDefinition.build(value); } \
            static int get(PyObject* obj, TEnum& value) { return enumDefinition.get(obj, value); } \
        }; \
    } \
    } \
    /**/
 
/** Defines the enumDefinition with name only for `enum.IntEnum`.
 *  @param t_cppEnum C++ enum type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @sa lass::python::IntEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_INT_ENUM_NAME(t_cppEnum, s_name) \
    ::lass::python::IntEnumDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name);
 
/** Defines the enumDefinition with name and docstring for `enum.IntEnum`.
 *  @param t_cppEnum C++ enum type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @param s_doc Documentation string (const char* string with static storage duration, or nullptr)
 *  @sa lass::python::IntEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_INT_ENUM_NAME_DOC(t_cppEnum, s_name, s_doc) \
    ::lass::python::IntEnumDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name, s_doc);
 
/** Defines the enumDefinition for initialization with constructor arguments for `enum.IntEnum`.
 *  Use this with initializer list: PY_DECLARE_INT_ENUM_EX(MyEnum)("MyEnum", "docs", { ... });
 *  @param t_cppEnum C++ enum type
 *  @sa lass::python::IntEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_INT_ENUM_EX(t_cppEnum) \
    ::lass::python::IntEnumDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition
 
/** @} */
 
 
 
/** @addtogroup EnumDefinition
 *  @name Integer Flag Support
 *  Macros for exporting C++ flag enums as Python `enum.IntFlag` types with bitwise operations.
 *  @{
 */
 
/** Specializes PyExportTraits for a C++ enum using `enum.IntFlag`.
 *  Use this in header files for bitfield enums, then use PY_DECLARE_INT_FLAG_* in source files.
 *  @param dllInterface Export specification (e.g., LASS_DLL_EXPORT)
 *  @param t_cppEnum C++ enum type (should be a bitfield enum)
 *  @sa lass::python::IntFlagDefinition
 *  @sa lass::python::FlagBoundary
 *  @ingroup EnumDefinition
 */
#define PY_SHADOW_INT_FLAG(dllInterface, t_cppEnum)\
    namespace lass \
    { \
    namespace python \
    { \
        template <> \
        struct PyExportTraits<t_cppEnum> \
        { \
            using TEnum = t_cppEnum; \
            using TEnumDefinition = IntFlagDefinition<TEnum>; \
            static dllInterface TEnumDefinition enumDefinition; \
            static PyObject* build(TEnum value) { return enumDefinition.build(value); } \
            static int get(PyObject* obj, TEnum& value) { return enumDefinition.get(obj, value); } \
        }; \
    } \
    } \
    /**/
 
/** Defines the enumDefinition with name only for `enum.IntFlag`.
 *  @param t_cppEnum C++ enum type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @sa lass::python::IntFlagDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_INT_FLAG_NAME(t_cppEnum, s_name) \
    ::lass::python::IntFlagDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name);
 
/** Defines the enumDefinition with name and docstring for `enum.IntFlag`.
 *  @param t_cppEnum C++ enum type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @param s_doc Documentation string (const char* string with static storage duration, or nullptr)
 *  @sa lass::python::IntFlagDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_INT_FLAG_NAME_DOC(t_cppEnum, s_name, s_doc) \
    ::lass::python::IntFlagDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name, s_doc);
 
/** Defines the enumDefinition for initialization with constructor arguments for `enum.IntFlag`.
 *  Use with: PY_DECLARE_INT_FLAG_EX(MyEnum)("MyEnum", "docs", FlagBoundary::Keep, { ... });
 *  @param t_cppEnum C++ enum type
 *  @sa lass::python::IntFlagDefinition
 *  @sa lass::python::FlagBoundary
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_INT_FLAG_EX(t_cppEnum) \
    ::lass::python::IntFlagDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition
 
/** @} */
 
 
 
/** @addtogroup EnumDefinition
 *  @name Generic Enum Support
 *  Macros for exporting C++ enums as Python `enum.Enum` types with custom value types.
 *  @{
 */
 
/** Specializes PyExportTraits for a C++ enum using generic `enum.Enum`.
 *  Use this in header files for enums with custom value types, then use PY_DECLARE_ENUM_* in source files.
 *  @param dllInterface Export specification (e.g., LASS_DLL_EXPORT)  
 *  @param t_cppEnum C++ enum type
 *  @param t_valueType Python value type for enum values
 *  @sa lass::python::EnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_SHADOW_ENUM(dllInterface, t_cppEnum, t_valueType)\
    namespace lass \
    { \
    namespace python \
    { \
        template <> \
        struct PyExportTraits<t_cppEnum> \
        { \
            using TEnum = t_cppEnum; \
            using TEnumDefinition = EnumDefinition<TEnum, t_valueType>; \
            static dllInterface TEnumDefinition enumDefinition; \
            static PyObject* build(TEnum value) { return enumDefinition.build(value); } \
            static int get(PyObject* obj, TEnum& value) { return enumDefinition.get(obj, value); } \
        }; \
    } \
    } \
    /**/
 
/** Defines the enumDefinition with name only for generic `enum.Enum`.
 *  @param t_cppEnum C++ enum type
 *  @param t_valueType Python value type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @sa lass::python::EnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_ENUM_NAME(t_cppEnum, t_valueType, s_name) \
    ::lass::python::EnumDefinition<t_cppEnum, t_valueType> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name);
 
/** Defines the enumDefinition with name and docstring for generic `enum.Enum`.
 *  @param t_cppEnum C++ enum type
 *  @param t_valueType Python value type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @param s_doc Documentation string (const char* string with static storage duration, or nullptr)
 *  @sa lass::python::EnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_ENUM_NAME_DOC(t_cppEnum, t_valueType, s_name, s_doc) \
    ::lass::python::EnumDefinition<t_cppEnum, t_valueType> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name, s_doc);
 
/** Defines the enumDefinition for initialization with constructor arguments for generic `enum.Enum`.
 *  Use with: PY_DECLARE_ENUM_EX(MyEnum, std::string)("MyEnum", "docs", { ... });
 *  @param t_cppEnum C++ enum type
 *  @param t_valueType Python value type
 *  @sa lass::python::EnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_ENUM_EX(t_cppEnum, t_valueType) \
    ::lass::python::EnumDefinition<t_cppEnum, t_valueType> lass::python::PyExportTraits<t_cppEnum>::enumDefinition
 
/** @} */
 
 
 
/** @addtogroup EnumDefinition
 *  @name String Enum Support
 *  Macros for exporting C++ enums as Python `enum.StrEnum` types with string values.
 *  @{
 */
 
/** Specializes PyExportTraits for a C++ enum using `enum.StrEnum`.
 *  Use this in header files for string-based enums, then use PY_DECLARE_STR_ENUM_* in source files.
 *  @param dllInterface Export specification (e.g., LASS_DLL_EXPORT)
 *  @param t_cppEnum C++ enum type
 *  @sa lass::python::StrEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_SHADOW_STR_ENUM(dllInterface, t_cppEnum)\
    namespace lass \
    { \
    namespace python \
    { \
        template <> \
        struct PyExportTraits<t_cppEnum> \
        { \
            using TEnum = t_cppEnum; \
            using TEnumDefinition = StrEnumDefinition<TEnum>; \
            static dllInterface TEnumDefinition enumDefinition; \
            static PyObject* build(TEnum value) { return enumDefinition.build(value); } \
            static int get(PyObject* obj, TEnum& value) { return enumDefinition.get(obj, value); } \
        }; \
    } \
    }
 
/** Defines the enumDefinition with name only for `enum.StrEnum`.
 *  @param t_cppEnum C++ enum type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @sa lass::python::StrEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_STR_ENUM_NAME(t_cppEnum, s_name) \
    ::lass::python::StrEnumDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name);
 
/** Defines the enumDefinition with name and docstring for `enum.StrEnum`.
 *  @param t_cppEnum C++ enum type
 *  @param s_name Python enum name (const char* string with static storage duration)
 *  @param s_doc Documentation string (const char* string with static storage duration, or nullptr)
 *  @sa lass::python::StrEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_STR_ENUM_NAME_DOC(t_cppEnum, s_name, s_doc) \
    ::lass::python::StrEnumDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition(s_name, s_doc);
 
/** Defines the enumDefinition for initialization with constructor arguments for `enum.StrEnum`.
 *  Use with: PY_DECLARE_STR_ENUM_EX(MyEnum)("MyEnum", "docs", { ... });
 *  @param t_cppEnum C++ enum type
 *  @sa lass::python::StrEnumDefinition
 *  @ingroup EnumDefinition
 */
#define PY_DECLARE_STR_ENUM_EX(t_cppEnum) \
    ::lass::python::StrEnumDefinition<t_cppEnum> lass::python::PyExportTraits<t_cppEnum>::enumDefinition
 
/** @} */
 
 
 
/** @addtogroup EnumDefinition
 *  @name Common Enum Utilities
 *  Utility macros for adding enum definitions to modules and classes.
 *  @{
 */
 
/** Adds an enum definition to a Python module.
 *  Use this after declaring the enum with PY_DECLARE_*_ENUM_* macros.
 *  The enum will be accessible as module.EnumName in Python.
 *  @param i_module Module variable identifier (must be unscoped identifier for token concatenation)
 *  @param t_cppEnum C++ enum type
 * 
 *  @par Usage Example:
 *  ```cpp
 *  // In header:
 *  PY_SHADOW_INT_ENUM(LASS_DLL_EXPORT, MyEnum);
 * 
 *  // In source:
 *  PY_DECLARE_MODULE_DOC(mymodule, "MyModule documentation");
 *  PY_MODULE_ENUM(mymodule, MyEnum);
 *  ```
 * 
 *  @note this must be called in the same translation unit (source file) that declares the module
 *        with `PY_DECLARE_MODULE_*` macros.
 *
 *  @ingroup EnumDefinition
 */
#define PY_MODULE_ENUM( i_module, t_cppEnum ) \
    LASS_EXECUTE_BEFORE_MAIN_EX\
    ( LASS_CONCATENATE( lassExecutePyModuleEnum_, i_module ),\
        i_module.addEnum( &::lass::python::PyExportTraits<t_cppEnum>::enumDefinition ); \
    )
 
/** Adds an enum definition as a nested enum to a Python class.
 *  Use this after declaring the enum with PY_DECLARE_*_ENUM_* macros.
 *  The enum will be accessible as ClassName.EnumName in Python.
 *  @param i_cppClass C++ class identifier (must be unscoped identifier for token concatenation)
 *  @param t_cppEnum C++ enum type
 * 
 *  @par Usage Example:
 *  ```cpp
 *  // In header:
 *  PY_SHADOW_INT_ENUM(LASS_DLL_EXPORT, MyEnum);
 * 
 *  // In source:
 *  PY_DECLARE_CLASS_NAME(MyClass, "MyClass documentation");
 *  PY_CLASS_ENUM(MyClass, MyEnum);
 *  ```
 
 *  @note this must be called in the same translation unit (source file) that declares the class
 *        with `PY_DECLARE_CLASS_*` macros.
 *
 *  @ingroup EnumDefinition
 */
#define PY_CLASS_ENUM( i_cppClass, t_cppEnum ) \
    LASS_EXECUTE_BEFORE_MAIN_EX\
    ( LASS_CONCATENATE( lassExecutePyClassEnum_, i_cppClass ),\
        i_cppClass ::_lassPyClassDef.addInnerEnum( &::lass::python::PyExportTraits<t_cppEnum>::enumDefinition ); \
    )
 
/** @} */