Ligare.programming.patterns

final class Ligare.programming.patterns.Singleton(cls_name: str, bases: tuple[Type[Any]], members: dict[str, Any])

Singleton metaclass. Create a new Singleton type by setting that class’s metaclass:

class Foo(metaclass=Singleton): …

Classes created as Singletons should be considered @final.

By default, the classes created by Singleton cannot have their attributes changed. To change this behavior, define an attribute named _block_change whose value is False. Not defining this attribute, or setting any other value, uses the default behavior. Be _VERY CAREFUL_ when using _block_change = False as Singleton is _NOT_ threadsafe. Note also that it is not possible to prevent the deletion of _class_ attributes.

For example, these are all equivalent: ``` class Foo(metaclass=Singleton): …

class Foo(metaclass=Singleton):

_block_change = True

class Foo(metaclass=Singleton):

_block_change = None

class Foo(metaclass=Singleton):

_block_change = 123

```

While this example is how to enable changes of attributes. ``` class Foo(metaclass=Singleton):

_block_change = False

```

class InstanceValue(value)

__init__(value)

property deleted

property value

static __new__(cls, cls_name, bases, members)

Modules

dependency_injection
singleton	Module containg Singleton metaclass