API

Package absence

A sentinel for absent values, distinct from None, with support for creating package-specific absence sentinels. Particularly useful in contexts where None is a valid value but you need to detect the absence of a value.

  • absent: Global sentinel representing absence, with falsey behavior and identity-based equality.

  • AbsenceFactory: Creates package-specific absence sentinels with customizable string representations.

  • Absential: Type alias for values that may be absent, supporting clear type hints.

  • is_absent: Type-safe predicate for checking if a value is the global absence sentinel.

  • is_absence: Type-safe predicate for checking if a value is any absence sentinel.

  • install: Optional function to install absence sentinel and predicates as builtins.

Module absence.objects

Absence sentinel factory, global singleton, and helper functions.

class absence.objects.AbsenceFactory(repr_function: Annotated[Callable[[Self], str] | None, Doc(' Function for __repr__. ')] | None = None, str_function: Annotated[Callable[[Self], str] | None, Doc(' Function for __str__. ')] | None = None)

Bases: Falsifier

Produces arbitrary absence sentinels.

class absence.objects.AbsentSingleton

Bases: AbsenceFactory

Produces global absence sentinel.

absence.objects.is_absence(value: object) → TypeIs[AbsenceFactory]

Checks if value is an absence sentinel.

absence.objects.is_absent(value: object) → TypeIs[AbsentSingleton]

Checks if value is the global absence sentinel.

Module absence.installers

Convenience to expose global sentinel and sentinel checker in builtins.

absence.installers.install(sentinel_name: Annotated[str | None, Doc(' Name to use for sentinel in builtins. ``None`` to skip. ')] = 'Absent', predicate_name: Annotated[str | None, Doc(' Name to use for predicate in builtins. ``None`` to skip. ')] = 'isabsent') → None

Installs absence sentinel and predicate as builtins.

Module absence.exceptions

Family of exceptions for package API.

  • Omniexception: Base for all package exceptions

  • Omnierror: Base for all package errors

exception absence.exceptions.Omnierror

Bases: Omniexception, Exception

Base for error exceptions raised by package API.

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args
exception absence.exceptions.Omniexception

Bases: ImmutableObject, BaseException

Base for all exceptions raised by package API.

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args
exception absence.exceptions.OperationValidityError(name: str)

Bases: Omnierror, RuntimeError, TypeError

Attempt to perform invalid operation.

with_traceback()

Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

args