https://github.com/avakar/typedobject

Define real, inheritable, and efficient Python classes using annotated variable syntax
https://github.com/avakar/typedobject

python

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Define real, inheritable, and efficient Python classes using annotated variable syntax

• Host: GitHub
• URL: https://github.com/avakar/typedobject
• Owner: avakar
• License: 0bsd
• Created: 2020-03-25T14:54:41.000Z (about 5 years ago)
• Default Branch: master
• Last Pushed: 2020-04-15T16:01:42.000Z (about 5 years ago)
• Last Synced: 2025-04-12T19:57:41.452Z (about 2 months ago)
• Topics: python
• Language: Python
• Homepage:
• Size: 11.7 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# typedobject

Define real, inheritable, and efficient Python classes using `TypedDict`-like

syntax.

## Getting started

Install from pip.

    python -m pip install typedobject

Then, annotate your class with `typedobject` and declare its member fields

using variable annotations.

    from typedobject import typedobject

    @typedobject

    class Point:

        x: int

        y: int

Then construct the object using either positional or keyword arguments.

    pt1 = Point(10, 20)

    pt2 = Point(x=10, y=20)

    assert pt1 == pt2

You can define methods, including `__init__`.

    @typedobject

    class Rectangle:

        pt1: Point

        pt2: Point

        def __init__(self, x1, y1, x2, y2):

            self.pt1 = Point(x1, y1)

            self.pt2 = Point(x2, y2)

        def area(self):

            return (self.pt2.x - self.pt1.x) * (self.pt2.y - self.pt1.y)

    rect = Rectangle(1, 1, 3, 3)

    assert rect.area() == 4

Unlike `TypedDict`, the defined classes are actually fresh new classes,

not `dict`s.

    assert isinstance(rect, Rectangle)

    assert not isinstance(rect, Point)

Inheritance works just fine.

    @typedobject

    class RoundedRect(Rectangle):

        corner_radius: int

    rr = RoundedRect(Point(1, 1), Point(3, 3), 1)

Note that the derived class overrides `__init__`, unless you use `.no_init`.

    @typedobject.no_init

    class RoundedRect2(Rectangle):

        corner_radius: int

    rr = RoundedRect2(1, 1, 3, 3)

    assert not hasattr(rr, 'corner_radius')

Typed object classes, unlike `dataclass`, specify `__slots__`, which makes

access to attributes faster and makes objects take less memory, but prevents

adding new fields dynamically.

They also prevent multiple inheritance.

    # raises TypeError

    class RectangleWithAPoint(Rectangle, Point):

        pass

You can, however, inject mixins.

    class TwoDObjectMixin:

        def area(self):

            return self.width() * self.height()

    @typedobject

    class Rectangle2(TwoDObjectMixin):

        pt1: Point

        pt2: Point