classicle

Provides immutable constant namespaces with dataclass-like ergonomics. See the Python discussion thread for context, motivation, and alternative approaches.

Example:

from classicle import FrozenSpace

class Config(FrozenSpace):
    HOST = "localhost"
    PORT: int = 8080  # add type hints only when you want them
    DEBUG = True


print(Config.HOST)  # "localhost"; Type checker knows this is a str
print(Config.PORT)  # 8080
config_dict = dict(Config)
# {'HOST': 'localhost', 'PORT': 8080, 'DEBUG': True}

# Iterate over attributes
for name, value in Config.items():
    print(f"{name} = {value}")

Features

• Type checker friendly
• No instantiation needed: The class itself is the namespace (cannot be instantiated)
• Immutable: Attributes cannot be modified (at the top level) or deleted after creation
• Mapping protocol: Supports dict(), len(), in, iteration, .items(), .keys(), .values()

Immutability

class Constants(FrozenSpace):
    PI = 3.14159
    E = 2.71828

# This will raise an AttributeError
try:
    Constants.PI = 3.14
except AttributeError as e:
    print(e)  # "Cannot modify attribute 'PI' on frozen namespace"

# This will also raise an AttributeError
try:
    del Constants.E
except AttributeError as e:
    print(e)  # "Cannot delete attribute 'E' on frozen namespace"

# Cannot instantiate FrozenSpace classes
try:
    instance = Constants()
except TypeError as e:
    print(e)  # "Cannot instantiate Constants..."

Installation

Install classicle: We're on pypi, so uv add classicle. If working directly on this repo, consider using the simplest-possible virtual environment.