https://github.com/pawelzny/vo

DDD Value Object implementation
https://github.com/pawelzny/vo

data ddd-patterns object python3 value

Last synced: 4 months ago
JSON representation

DDD Value Object implementation

• Host: GitHub
• URL: https://github.com/pawelzny/vo
• Owner: pawelzny
• License: isc
• Created: 2017-03-12T15:19:19.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2022-12-08T02:03:23.000Z (over 3 years ago)
• Last Synced: 2025-11-28T15:34:30.231Z (7 months ago)
• Topics: data, ddd-patterns, object, python3, value
• Language: Python
• Homepage: http://vo.readthedocs.io
• Size: 97.7 KB
• Stars: 2
• Watchers: 0
• Forks: 0
• Open Issues: 7
• Metadata Files:
  • Readme: README.rst
  • Contributing: CONTRIBUTING.rst
  • License: LICENSE

Awesome Lists containing this project

README

          
************

Value Object

************

:Info: DDD Value Object implementation.

:Author: Paweł Zadrożny @pawelzny 

.. image:: https://circleci.com/gh/pawelzny/vo/tree/master.svg?style=shield&circle-token=bcc877f72e384d82ddd044b88de1faca2ff774bc

   :target: https://circleci.com/gh/pawelzny/vo/tree/master

   :alt: CI Status

.. image:: https://readthedocs.org/projects/vo/badge/?version=latest

   :target: http://vo.readthedocs.io/en/latest/?badge=latest

   :alt: Documentation Status

.. image:: https://img.shields.io/pypi/v/vo.svg

   :target: https://pypi.org/project/vo/

   :alt: PyPI Repository Status

.. image:: https://img.shields.io/github/release/pawelzny/vo.svg

   :target: https://github.com/pawelzny/vo

   :alt: Release Status

.. image:: https://img.shields.io/pypi/status/vo.svg

   :target: https://pypi.org/project/vo/

   :alt: Project Status

.. image:: https://img.shields.io/pypi/pyversions/vo.svg

   :target: https://pypi.org/project/vo/

   :alt: Supported python versions

.. image:: https://img.shields.io/pypi/implementation/vo.svg

   :target: https://pypi.org/project/vo/

   :alt: Supported interpreters

.. image:: https://img.shields.io/pypi/l/vo.svg

   :target: https://github.com/pawelzny/vo/blob/master/LICENSE

   :alt: License

Features

========

* Value Objects are immutable.

* Two objects with the same values are considered equal

* Access to values with dot notation: ``value.my_attr``

* Access to values by key: ``value['my_attr']``

Installation

============

.. code:: bash

    pipenv install vo  # or pip install vo

**Package**: https://pypi.org/project/vo/

Documentation

=============

* Full documentation: http://vo.readthedocs.io

* Public API: http://vo.readthedocs.io/en/latest/api.html

* Examples and usage ideas: http://vo.readthedocs.io/en/latest/examples.html

Quick Example

=============

Value accept any ``key=value`` pairs. These pairs will be attached to object as attributes.

Once created values are immutable. Attributes can't be changed or deleted.

.. code-block:: python

   >>> from vo import Value

   >>> book = Value(title='Learning Python',

   ...              authors=['Mark Lutz', 'David Ascher'],

   ...              publisher="O'REILLY")

   >>> book

   Value(authors=['Mark Lutz', 'David Ascher'], publisher="O'REILLY", title='Learning Python')

   >>> str(book)

   '{"authors": ["Mark Lutz", "David Ascher"], "publisher": "O\'REILLY", "title": "Learning Python"}'

.. warning:: Any attempt of value modification or delete will raise ``ImmutableInstanceError``

.. code-block:: python

   >>> from vo import Value

   >>> book = Value(title='Learning Python',

   ...              authors=['Mark Lutz', 'David Ascher'],

   ...              publisher="O'REILLY")

   >>> book.title = 'Spam'

   Traceback (most recent call last):

     File "", line 1, in 

       raise ImmutableInstanceError()

     vo.value.ImmutableInstanceError: Modification of Value frozen instance is forbidden.

Values access

-------------

Values can be accessed like object attributes or like dict keys.

.. code-block:: python

   >>> from vo import Value

   >>> book = Value(title='Learning Python',

   ...              authors=['Mark Lutz', 'David Ascher'],

   ...              publisher="O'REILLY")

   >>> book.title == book['title']

   True

   >>> book.authors == book['authors']

   True

Objects comparison

------------------

Let's take the same book example.

.. code-block:: python

   >>> from vo import Value

   >>> book1 = Value(title='Learning Python',

   ...               authors=['Mark Lutz', 'David Ascher'],

   ...               publisher="O'REILLY")

   >>> book2 = Value(title='Learning Python',

   ...               authors=['Mark Lutz', 'David Ascher'],

   ...               publisher="O'REILLY")

   >>> book1 == book2

   True

   >>> book1 is book2

   False

Value lookup

------------

Check if value exists.

.. code-block:: python

   >>> from vo import Value

   >>> book = Value(title='Learning Python',

   ...              authors=['Mark Lutz', 'David Ascher'],

   ...              publisher="O'REILLY")

   >>> 'title' in book

   True

   >>> 'price' in book

   False

   >>> book.title

   'Learning Python'

   >>> book.price

   Traceback (most recent call last):

     File "", line 1, in 

   AttributeError: 'Value' object has no attribute 'price'