https://github.com/jcomo/immut

An immutable container library for python
https://github.com/jcomo/immut

Last synced: 2 months ago
JSON representation

An immutable container library for python

• Host: GitHub
• URL: https://github.com/jcomo/immut
• Owner: jcomo
• Created: 2015-01-02T20:32:13.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2022-12-26T20:15:09.000Z (about 2 years ago)
• Last Synced: 2024-11-07T14:53:02.747Z (3 months ago)
• Language: Python
• Size: 16.6 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 2
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
# Immut

An immutable container library for Python

![](https://travis-ci.org/jcomo/immut.svg?branch=master)

## Use case

The intended use case for this library is to create named immutable container classes

to use in an application. This would be particularly useful for value objects. Create

an immutable container to hold a bunch of data with named fields and pass it freely

around the application knowing that the contents will not be modified after creation.

## Example usage

```

pip install immut

```

```python

from immut import ImmutableContainer

ResponseModel = ImmutableContainer('ResponseModel', 'message', 'code')

response = ResponseModel(message='success')

response.message  # returns 'success'

response.code  # returns None

# The fields can be anything

u = User('jonathan')

RequestModel = ImmutableContainer('RequestModel', 'user')

request = RequestModel(user=u)

```

## API

The sole API is for creating a container.

```python

ImmutableContainer(container_name, *fields)

```

**Parameters**

* `container_name` the name of the class for the container (string). Generally, simply set it to the name of the variable

you are assigning to.

* `fields` each field is a string representing the fields that this container will have

**Returns**

A dynamically generated immutable container

**Behavior**

* Trying to set a specified field on the immutable container after creation will raise an `AttributeError`.

* Setting a *non-specified* field in the constructor will raise a `ValueError`

  * Setting a non-specified field on the container after construction is allowed, but is not recommended as it is

  outside the scope of the use case and is bad python programming practice in general.

* Non-initialized fields in the constructor will return `None` when accessed.

### Disclaimer

I know this isn't the most pythonic or useful library in the world. It was conceived

as a way for me to learn how meta classes work. However, it has its uses, and it is

well tested.

##### Differences with `collections.namedtuple`

There are many similarities with this library and `collections.namedtuple`. The main difference is in the behavior with initialization. With a namedtuple, each defined attribute must be initialized in the constructor but with this container library, attributes are initialized to None by default if they are unspecified in the constructor.