OLD Class Inheritance Concept Docs

This issue describes how to implement the class-inheritance concept docs.

Getting started

Please please please read the docs before starting. Posting PRs without reading these docs will be a lot more frustrating for you during the review cycle, and exhaust Exercism’s maintainers’ time. So, before diving into the implementation, please read up on the following documents:

• Contributing to Exercism | Exercism and GitHub | - Contributor Pull Request Guide
• What are those Weird Task Tags about?
• Building Language Tracks: An Overview
• What are Concepts?
• Concept Specifications
• Exercism Formatting and Style Guide
• Exercism Markdown Specification
• Reputation

Goal

This concept is meant to teach an understanding/use of class-inheritance in Python.

Learning objectives

• more fully understand the uses (and possible abuses) of classes in Python
• understanding and use of single inheritance in Python
• understanding and use of multiple inheritance in Python
  • the diamond inheritance problem
  • Pythons MRO (method resolution order)
  • pros and cos of mixins () to isolate multiple inheritance issues
• when and when not to use __super__() to call a parent class constructor

Out of scope

• class-composition as an explicit topic (it is ok to use limited composition as needed in example code)
• dataclasses
• decorators outside of @property, @staticmethod, and @classmethod (the student should already be exposed to these in the prerequisite exercise)
• generators
• coroutines
• descriptors (these will get their own exercise)
• using a class as a decorator
• performance considerations

Concepts

• classes
• inheritance in OOP
• single inheritance
• multiple inheritance
• minxins
• __super__()

Prerequisites

These are the concepts/concept exercises the student needs to complete/understand before solving the concept exercise that these concept documents support.

• basics
• booleans
• classes
• class-customization
• comparisons
• decorators
• dicts
• functions
• higher-order-functions
• iteration
• lists
• numbers
• sequences
• sets
• strings
• tuples

Resources to refer to

• classes (Python tutorial)
• Real Python: Object-Oriented Programming in Python 3
• Real Python: Inheritance and Composition: A Python OOP Guide
• Towards DataScience: Understand Inheritance in Python – (this is not a good resource for hints or links, since it requires an account signup)
  • Liskov substitution principle
• Multiple Inheritance in Python
• Multiple Inheritance is Hard (Ned Batchelder)
• Python.org: MRO in Python 2.3+
• Dig into Python super() and MRO
• Multiple inheritance and mixin classes in Python
• Making Python classes more modular using mixins
• Write composable, reusable Python classes using Mixinsl)
• Mixins in Python and Ruby Compared
• Python Data Model - Python Docs

• links.json

  For more information, see concept links file

  • The same resources listed in this issue can be used as a starting point for the concepts/links.json file, if it doesn’t already exist.
  • If there are particularly good/interesting information sources for this concept that extend or supplement the concept exercise material & the resources already listed – please add them to the links.json document.

Concept Description

Please see the following for more details on these files: concepts

• Concept about.md

  For more information, see Concept about.md

  • This file provides information about this concept for a student who has completed the corresponding concept exercise. It is intended as a reference for continued learning.

• Concept introduction.md

  For more information, see Concept introduction.md

  • This can also be a summary/paraphrase of the document listed above, and will provide a brief introduction of the concept for a student who has not yet completed the concept exercise. It should contain a good summation of the concept, but not go into lots of detail.

Implementation Notes

• Example code should only use syntax & concepts introduced within these docs or one of the prerequisite concept exercises or documents. Please do not use comprehensions, generator expressions, or other syntax not previously covered. Please also follow PEP8 guidelines.
• Our markdown and JSON files are checked against prettier . We recommend setting prettier up locally and running it prior to submitting your PR to avoid any CI errors.

Help

If you have any questions while implementing the exercise, please post the questions as comments in this issue, or contact one of the maintainers on our Slack channel.

[BethanyG]

Once you commented, I could assign. So now you are assigned. 😉

[BethanyG]

Closing, as the PR for this has been optimistically merged. Further changes and improvements will be tracked under an improvement issue. Many thanks for your work on this, @girijakar!