httk.core.views.backend

Classes

Backend

Abstract base class to be subclassed into classes that keep track of alternative

Module Contents

class httk.core.views.backend.Backend[BackendT: Backend](backend, **hints)

Bases: abc.ABC

Abstract base class to be subclassed into classes that keep track of alternative representations of certain types of data, all adhering to a common API interface.

The class variable backend_classes is a list of all classes that can carry the kind of data the subclass represents.

A system of “hints” are used primarily to disambiguate between multiple valid interpretations of the same input object. Unless otherwise documented for a specific backend, extra hints that do not affect this interpretation are ignored.

A set of backends are meant to be combined with a set of Views.

backend_classes: ClassVar[list[type[Backend[Any]]]]

classmethod create(obj: Any, **hints: Any) → Self

Given a source data (obj) and a set of hints, create a backend from one of the alternatives in the class variable backend_classes.

By design this creation depends heavily on order of the classes in backend_classes. Each class is tried in the order they appear until one of them is successful, in the sense that their __new__ does not return None. Sometimes multiple backend classes can handle the same input type. In that case, dispatch is guided by keyword arguments **hints, with the convention that:

• if a hint named kind is given, a backend class should accept the object only if it matches that kind;

• when kind matches, additional unrecognized hints may be ignored.

unwrap() → Any

Return the most raw representation possible of this backend, i.e., if it uses a backend with an internal representaion - or if it can (possibly lossly) convert itself into a more raw representation that still would be recognized as a <Something>Like type, that representation will be returned. If this is not possible, the instance itself is returned.