frigid 4.2
Immutable data structures.
Requires Python: >=3.10
Keywords: api, dictionary, immutability, immutable, namespace

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*******************************************************************************
                                     frigid
*******************************************************************************

.. image:: https://img.shields.io/pypi/v/frigid
   :alt: Package Version
   :target: https://pypi.org/project/frigid/

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   :alt: Code Coverage Percentage
   :target: https://github.com/emcd/python-frigid/actions/workflows/tester.yaml

.. image:: https://img.shields.io/github/license/emcd/python-frigid
   :alt: Project License
   :target: https://github.com/emcd/python-frigid/blob/master/LICENSE.txt

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🔒 A Python library package which provides **immutable data structures** -
collections which cannot be modified after creation.


Key Features ⭐
===============================================================================

* 📖 **Immutable Dictionary**: Like a regular `dict
  <https://docs.python.org/3/library/stdtypes.html#dict>`_, but entries cannot
  be modified or removed. Also has variant for validation on initialization.
  And provides set operations not found on `MappingProxyType
  <https://docs.python.org/3/library/types.html#types.MappingProxyType>`_.
* 🗃️ **Immutable Namespace**: Similar to `SimpleNamespace
  <https://docs.python.org/3/library/types.html#types.SimpleNamespace>`_, but
  attributes are immutable from creation.
* 🧱 **Additional Types**: Classes (including abstract base classes), modules,
  and objects with immutable behavior.
* 🏗️ **Flexible Initialization**: Support for unprotected attributes during
  initialization; useful for compatibility with class decorators, such as
  `dataclasses
  <https://docs.python.org/3/library/dataclasses.html#dataclasses.dataclass>`_.
* 🔓 **Flexible Mutability**: Support for declaring specific attributes as
  mutable, enabling selective modification while maintaining immutability for
  other attributes.


Installation 📦
===============================================================================

Method: Install Python Package
-------------------------------------------------------------------------------

Install via `uv <https://github.com/astral-sh/uv/blob/main/README.md>`_ ``pip``
command:

::

    uv pip install frigid

Or, install via ``pip``:

::

    pip install frigid


Note on Immutability 📢
===============================================================================

   Enforcement of immutability is quite difficult in Python. While this library
   enforces immutability by default, it can be circumvented by anyone who has
   intermediate knowledge of Python machinery and who is determined to
   circumvent the immutability. Use the library in the spirit of making
   programs safer, but understand that it cannot truly prevent unwanted state
   tampering.


Examples 💡
===============================================================================


Immutable Namespaces 🗃️
-------------------------------------------------------------------------------

An immutable namespace, similar to ``types.SimpleNamespace``, is available.
This namespace can be initialized from multiple iterables and from keyword
arguments. (Keyword arguments shown below; see documentation for additional
forms of initialization.)

>>> from frigid import Namespace
>>> ns = Namespace( apples = 12, bananas = 6 )
>>> ns.cherries = 42    # ❌ Attempted assignment raises error.
Traceback (most recent call last):
...
frigid.exceptions.AttributeImmutability: Could not assign or delete attribute 'cherries'.
>>> del ns.apples       # ❌ Attempted deletion raises error.
Traceback (most recent call last):
...
frigid.exceptions.AttributeImmutability: Could not assign or delete attribute 'apples'.
>>> ns
frigid.namespaces.Namespace( apples = 12, bananas = 6 )


Immutable Dictionaries 📖
-------------------------------------------------------------------------------

An immutable dictionary, similar to ``dict``, is available. This dictionary can
be initialized from multiple iterables and from keyword arguments. (Keyword
arguments shown below; see documentation for additional forms of
initialization.)

>>> from frigid import Dictionary
>>> dct = Dictionary( apples = 12, bananas = 6)
>>> dct['cherries'] = 42  # ❌ Attempted assignment raises error.
Traceback (most recent call last):
...
frigid.exceptions.EntryImmutability: Cannot assign entry for 'cherries'.
>>> del dct['bananas']    # ❌ Attempted removal raises error.
Traceback (most recent call last):
...
frigid.exceptions.EntryImmutability: Cannot delete entry for 'bananas'.
>>> dct
frigid.dictionaries.Dictionary( {'apples': 12, 'bananas': 6} )


Immutable Objects 🧱
-------------------------------------------------------------------------------

The ``with_standard_behaviors`` decorator can be applied to any class to make
its instances fully immutable after initialization.

>>> from frigid import with_standard_behaviors
>>> @with_standard_behaviors( )
... class Config:
...     def __init__( self, debug = False ):
...         self.debug = debug
...
>>> config = Config( debug = True )
>>> config.verbose = True  # ❌ Attempted addition raises error
Traceback (most recent call last):
...
frigid.exceptions.AttributeImmutability: Could not assign or delete attribute 'verbose'.
>>> config.debug = False   # ❌ Attempted reassignment raises error
Traceback (most recent call last):
...
frigid.exceptions.AttributeImmutability: Could not assign or delete attribute 'debug'.


Use Cases 🎯
===============================================================================

* 🔒 **Configuration Objects**: Objects which must maintain consistent state
  throughout program execution.
* 📊 **Value Objects**: Objects which represent values and should be immutable,
  like numbers or strings.
* 🧱 **Immutable Collections**: Many scenarios requiring collections with
  complete immutability guarantees.


Contribution 🤝
===============================================================================

Contribution to this project is welcome! However, it must follow the `code of
conduct
<https://emcd.github.io/python-project-common/stable/sphinx-html/common/conduct.html>`_
for the project.

Please file bug reports and feature requests in the `issue tracker
<https://github.com/emcd/python-frigid/issues>`_ or submit `pull
requests <https://github.com/emcd/python-frigid/pulls>`_ to
improve the source code or documentation.

For development guidance and standards, please see the `development guide
<https://emcd.github.io/python-frigid/stable/sphinx-html/contribution.html#development>`_.


Additional Indicia
===============================================================================

.. image:: https://img.shields.io/github/last-commit/emcd/python-frigid
   :alt: GitHub last commit
   :target: https://github.com/emcd/python-frigid

.. image:: https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/copier-org/copier/master/img/badge/badge-grayscale-inverted-border-orange.json
   :alt: Copier
   :target: https://github.com/copier-org/copier

.. image:: https://img.shields.io/badge/%F0%9F%A5%9A-Hatch-4051b5.svg
   :alt: Hatch
   :target: https://github.com/pypa/hatch

.. image:: https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit
   :alt: pre-commit
   :target: https://github.com/pre-commit/pre-commit

.. image:: https://microsoft.github.io/pyright/img/pyright_badge.svg
   :alt: Pyright
   :target: https://microsoft.github.io/pyright

.. image:: https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json
   :alt: Ruff
   :target: https://github.com/astral-sh/ruff

.. image:: https://img.shields.io/pypi/implementation/frigid
   :alt: PyPI - Implementation
   :target: https://pypi.org/project/frigid/

.. image:: https://img.shields.io/pypi/wheel/frigid
   :alt: PyPI - Wheel
   :target: https://pypi.org/project/frigid/


Other Projects by This Author 🌟
===============================================================================


* `python-absence <https://github.com/emcd/python-absence>`_ (`absence <https://pypi.org/project/absence/>`_ on PyPI)

  🕳️ A Python library package which provides a **sentinel for absent values** - a falsey, immutable singleton that represents the absence of a value in contexts where ``None`` or ``False`` may be valid values.
* `python-accretive <https://github.com/emcd/python-accretive>`_ (`accretive <https://pypi.org/project/accretive/>`_ on PyPI)

  🌌 A Python library package which provides **accretive data structures** - collections which can grow but never shrink.
* `python-classcore <https://github.com/emcd/python-classcore>`_ (`classcore <https://pypi.org/project/classcore/>`_ on PyPI)

  🏭 A Python library package which provides **foundational class factories and decorators** for providing classes with attributes immutability and concealment and other custom behaviors.
* `python-dynadoc <https://github.com/emcd/python-dynadoc>`_ (`dynadoc <https://pypi.org/project/dynadoc/>`_ on PyPI)

  📝 A Python library package which bridges the gap between **rich annotations** and **automatic documentation generation** with configurable renderers and support for reusable fragments.
* `python-falsifier <https://github.com/emcd/python-falsifier>`_ (`falsifier <https://pypi.org/project/falsifier/>`_ on PyPI)

  🎭 A very simple Python library package which provides a **base class for falsey objects** - objects that evaluate to ``False`` in boolean contexts.
* `python-icecream-truck <https://github.com/emcd/python-icecream-truck>`_ (`icecream-truck <https://pypi.org/project/icecream-truck/>`_ on PyPI)

  🍦 **Flavorful Debugging** - A Python library which enhances the powerful and well-known ``icecream`` package with flavored traces, configuration hierarchies, customized outputs, ready-made recipes, and more.
* `python-mimeogram <https://github.com/emcd/python-mimeogram>`_ (`mimeogram <https://pypi.org/project/mimeogram/>`_ on PyPI)

  📨 A command-line tool for **exchanging collections of files with Large Language Models** - bundle multiple files into a single clipboard-ready document while preserving directory structure and metadata... good for code reviews, project sharing, and LLM interactions.