oncequinox

Create singleton Equinox modules.

This is a micro-package, containing the single metaclass SingletonModuleMeta.
SingletonModuleMeta can be used to create Equinox modules that are singletons, meaning that only one instance of the module can exist at any given time.

Installation

pip install oncequinox

Documentation

Basic Usage

Create a singleton Equinox module:

import equinox as eqx
from oncequinox import SingletonModuleMeta


class MySingletonModule(eqx.Module, metaclass=SingletonModuleMeta):
    value: str = "this is a singleton module"


# Create the singleton instance
singleton1 = MySingletonModule()

# Attempt to create another instance
singleton2 = MySingletonModule()

print(singleton1 is singleton2)  # True

Singleton Per Class

Different classes maintain separate singleton instances:

import equinox as eqx
from oncequinox import SingletonModuleMeta


class ConfigA(eqx.Module, metaclass=SingletonModuleMeta):
    name: str = "A"


class ConfigB(eqx.Module, metaclass=SingletonModuleMeta):
    name: str = "B"


config_a = ConfigA()
config_b = ConfigB()

print(config_a is config_b)  # False
print(config_a.name)  # A
print(config_b.name)  # B

With Initialization Arguments

Arguments are only used for the first instantiation:

import equinox as eqx
from oncequinox import SingletonModuleMeta


class HasValue(eqx.Module, metaclass=SingletonModuleMeta):
    value: int

    def __init__(self, value: int):
        self.value = value


v1 = HasValue(10)
print(v1.value)  # 10

# Subsequent calls ignore arguments and return existing instance
v2 = HasValue(20)
print(v2.value)  # 10
print(v1 is v2)  # True