python-stdlib/enum/enum.py: Add Enum class.

python-stdlib/enum/enum.md

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+Below is the documentation for your `enum.py` library. This file explains the core concepts of your custom `Enum` implementation and provides practical examples for embedded development and general logic.
+
+---
+
+# Custom Enum Library for Python & MicroPython
+
+This library provides a flexible, memory-efficient `Enum` class designed for dynamic usage and seamless mathematical integration. Unlike the standard CPython `Enum`, this version allows for runtime expansion and direct arithmetic operations without needing to access a `.value` property.
+
+## Core Features
+* **Transparent Math**: Supports arithmetic (`+`, `-`, `*`, `/`) and bitwise (`&`, `|`, `^`, `<<`, `>>`) operations directly on enum members.
+* **Dynamic Expansion**: Add new members at runtime via `.append()` or direct attribute assignment.
+* **Memory Efficient**: Uses `__slots__` in the `ValueWrapper` to minimize RAM usage on platforms like the ESP32.
+* **Flexible Initialization**: Can be initialized via class inheritance, dictionaries, or keyword arguments.
+
+---
+
+## Usage Examples
+
+### 1. Hardware Pin Configuration (ESP32)
+Define your hardware pins using class inheritance. You can skip internal or reserved pins using the `__skipped__` attribute.
+
+```python
+from enum import Enum
+
+class Pins(Enum):
+    # Members defined at class level
+    LED = 2
+    BUTTON = 4
+    # Members to exclude from the enum mapping
+    __skipped__ = ('RESERVED_PIN',)
+    RESERVED_PIN = 0
+
+# You can also add pins during instantiation
+pins = Pins(SDA=21, SCL=22)
+
+print(f"I2C SDA Pin: {pins.SDA}") # Output: 21
+print(f"Is pin 21 valid? {pins.is_value(21)}") # Output: True
+```
+
+### 2. Math and Register Logic
+The `ValueWrapper` allows you to perform calculations directly. This is particularly useful for bitmasks and step-based logic.
+
+```python
+# Initialize with key-value pairs
+brightness = Enum(MIN=0, STEP=25, MAX=255)
+
+# Direct arithmetic (Forward and Reflected)
+next_level = brightness.MIN + brightness.STEP // 2
+complex_math = 100 + brightness.STEP 
+
+print(f"Next Level: {next_level}") # Output: 12
+print(f"Complex Math: {complex_math}") # Output: 125
+
+# Bitwise operations for register control
+flags = Enum(BIT_0=0x01, BIT_1=0x02)
+combined = flags.BIT_0 | flags.BIT_1
+print(f"Combined Flags: {hex(combined)}") # Output: 0x03
+```
+
+### 3. Dynamic State Machines
+You can expand an `Enum` as your program logic progresses, such as adding states to a connection manager.
+
+```python
+status = Enum(IDLE=0, CONNECTING=1)
+
+# Add multiple members via append()
+status.append(CONNECTED=2, ERROR=3)
+
+# Add a single member via direct assignment
+status.DISCONNECTING = 4
+
+for name, val in status.items():
+    print(f"Status {name} has code {val}")
+```
+
+### 4. Working with Different Data Types
+Enums are not restricted to integers; they can wrap strings, floats, and booleans.
+
+```python
+commands = Enum(
+    START="CMD_START",
+    STOP="CMD_STOP",
+    TIMEOUT=5.5,
+    IS_ACTIVE=True
+)
+
+if commands.IS_ACTIVE:
+    # Use str() to get the wrapped string value
+    print(f"Executing: {commands.START}") 
+```
+
+### 5. Introspection and Utilities
+The library provides helper methods to validate values or find keys based on their values.
+
+```python
+class ErrorCodes(Enum):
+    NOT_FOUND = 404
+    SERVER_ERROR = 500
+
+# Check if a value exists in the Enum
+exists = ErrorCodes.is_value(404) # True
+
+# Get the formatted string name from a value
+name = ErrorCodes.key_from_value(500) 
+print(name) # Output: ErrorCodes.SERVER_ERROR
+```
+
+---
+
+## API Reference
+
+### `ValueWrapper`
+The internal class that wraps values to enable mathematical transparency.
+* `.value`: Access the raw value.
+* `()`: Calling the object returns the raw value.
+
+### `Enum` (Inherits from `dict`)
+* `append(arg=None, **kwargs)`: Adds new members to the Enum.
+* `is_value(value)`: Returns `True` if the value exists in the Enum.
+* `key_from_value(value)`: Returns the string representation (e.g., `ClassName.KEY`) for a given value.

python-stdlib/enum/enum.py

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+# enum.py
+# version="1.2.2"
+
+
+class EnumValue:
+    # An immutable object representing a specific enum member
+    def __init__(self, value, name):
+        object.__setattr__(self, 'value', value)
+        object.__setattr__(self, 'name', name)
+
+    def __repr__(self):
+        return f"<{self.name}: {self.value}>"
+
+    def __str__(self):
+        return str(self.value)
+
+    def __call__(self):
+        return self.value
+
+    def __eq__(self, other):
+        if isinstance(other, EnumValue):
+            return self.value == other.value
+        return self.value == other
+
+    def __int__(self):
+        return self.value
+
+    def __setattr__(self, key, value):
+        raise AttributeError("EnumValue is immutable")
+
+
+class Enum:
+    def __new__(cls, *args, **kwargs):
+        # Scenario 1: Reverse lookup by value (e.g., Status(1))
+        if len(args) == 1:
+            if cls is not Enum:
+                return cls._lookup(args[0])
+            return super(Enum, cls).__new__(cls)
+
+        # Scenario 2: Restriction on multiple positional arguments
+        elif len(args) > 1:
+            raise TypeError(f"{cls.__name__}() takes at most 1 positional argument ({len(args)} given)")
+
+        # Scenario 3: Creating an instance (e.g. Color() або Color(BLUE=3))
+        return super(Enum, cls).__new__(cls)
+
+    def __init__(self, **kwargs):
+        # 1. Convert class-level attributes (constants) to EnumValue objects
+        self._scan_class_attrs()
+        # 2. Add dynamic arguments from constructor
+        if kwargs:
+            self.append(**kwargs)
+
+    @classmethod
+    def _lookup(cls, value):
+        # Finds an EnumValue by its raw value
+        for key in dir(cls):
+            if key.startswith('_'):
+                continue
+            attr = getattr(cls, key)
+            if isinstance(attr, EnumValue) and (attr.value == value or attr.name == value):
+                return attr
+            if not callable(attr) and attr == value:
+                # Wrap static numbers found in class definition
+                return EnumValue(attr, key)
+                return attr
+
+        raise AttributeError(f"{value} is not in {cls.__name__} enum")
+
+    def list_members(self):
+        # Returns a list of tuples (name, value) for all members
+        return [(m.name, m.value) for m in self]
+
+    def _update(self, key, value):
+        setattr(self.__class__, key, EnumValue(value, key))
+
+    def _scan_class_attrs(self):
+        # Converts static class attributes into EnumValue objects
+        # List of methods and internal names that should not be converted
+        ignored = ('append', 'is_value', 'list_members')
+        for key in dir(self.__class__):
+            # Skip internal names and methods
+            if key.startswith('_') or key in ignored:
+                continue
+
+            value = getattr(self.__class__, key)
+            # Convert only constants, not methods
+            if not callable(value) and not isinstance(value, EnumValue):
+                self._update(key, value)
+
+    def is_value(self, value):
+        return any(member.value == value for member in self)
+
+    def append(self, **kwargs):
+        # Adds new members dynamically.
+        for key, value in kwargs.items():
+            if hasattr(self, key):
+                raise AttributeError(f"Enum key '{key}' is immutable")
+            self._update(key, value)
+
+    def __repr__(self):
+        members = [f"{m.name}={m.value}" for m in self]
+        # Return a string like: Color(RED=1, GREEN=2, BLUE=3)
+        return f"{self.__class__.__name__}({', '.join(members)})"
+
+    def __call__(self, value):
+        for member in self:
+            if member.value == value:
+                return member
+        raise ValueError(f"no such value: {value}")
+
+    def __setattr__(self, key, value):
+        if hasattr(self, key) and isinstance(getattr(self, key), EnumValue):
+            raise AttributeError(f"Enum member '{key}' is immutable")
+        super().__setattr__(key, value)
+
+    def __delattr__(self, key):
+        if hasattr(self, key) and isinstance(getattr(self, key), EnumValue):
+            raise AttributeError("Enum members cannot be deleted")
+        super().__delattr__(key)
+
+    def __len__(self):
+        return sum(1 for _ in self)
+
+    def __iter__(self):
+        for key in dir(self.__class__):
+            attr = getattr(self.__class__, key)
+            if isinstance(attr, EnumValue):
+                yield attr
+
+
+def enum(**kwargs):  # `**kwargs` kept backwards compatible as in the Internet examples
+    return Enum(**kwargs)
+
+
+if __name__ == '__main__':
+    # --- Usage Example 1 ---
+    # 1. Creation via class
+    class Color(Enum):
+        RED = 1
+        GREEN = 2
+
+    # 2. Create instance
+    c = Color()
+    print(f"Enum repr c: {c}")
+
+    # 3. Dynamic addition
+    c.append(BLUE=3)
+    print(f"c after append: {c}")
+
+    print('dir(c):', dir(c))
+
+    # 4. Immutability and name protection check
+    try:
+        c.append(append=True)
+    except AttributeError as e:
+        print(f"\nAttributeError: Reserved name protection: {e}\n")
+
+    # 5. Basic access
+    print(f"RED: Name={c.RED.name}, Value={c.RED.value}, EnumValue={c.RED}, Call={c.RED()} ")
+
+    # 6. Assertions
+    assert c.RED == 1
+    assert c.RED.value == 1
+    assert c.RED.name == 'RED'
+
+    # 7. Reverse lookup
+    print(f"c(1) lookup object: {c(1)}, Name={c(1).name}")  # RED
+    assert c(1).name == 'RED'
+    assert c(1) == 1
+
+    # 8. Iteration
+    print("Values list:", [member.value for member in c])
+    print("Names list:", [member.name for member in c])
+
+    try:
+        c(7)
+    except ValueError as e:
+        print(f"\nValueError: {c} {e}\n")
+
+    # --- Usage Example 2 ---
+    # 1. Define an Enum class
+    class Status(Enum):
+        IDLE = 0
+        RUNNING = 1
+        ERROR = 2
+
+    # 2. Test: Reverse Lookup
+    # This simulates receiving a byte from the  hardware
+    received_byte = 1
+    status = Status(received_byte)
+    print(f"Lookup check: Received {received_byte} -> {status!r}")
+    assert status == Status.RUNNING
+    assert status.name == "RUNNING"
+
+    # 3. Test: Comparisons
+    print(f"Comparison check: {status} == 1 is {status == 1}")
+    assert status == 1
+    assert status != 0
+    assert status == Status.RUNNING
+
+    # 4. Test: Immutability
+    try:
+        Status.RUNNING.value = 99
+    except AttributeError as e:
+        print(f"\nImmutability check: Passed (Cannot modify EnumValue): {e}\n")
+
+    # 5. Test: Dynamic Append
+    powers = Enum()
+    powers.append(LOW=10, HIGH=100)
+    print(f"Dynamic Enum check: {powers}")
+    assert powers.LOW == 10
+
+    # 6. Test: Iteration
+    print("Iteration check: ", end="")
+    for m in Status():
+        print(f"{m.name}, ", end="")
+    print("-> Passed")
+
+    # 7. Test: Error handling for invalid lookup
+    try:
+        Status(99)
+    except AttributeError as e:
+        print(f"\nAttributeError: Invalid lookup check: Caught expected error -> {e}\n")
+
+    print("\nAll tests passed successfully!")