OLD class-inheritance concept exercise

[BethanyG]

This issue describes how to implement the class-inheritance concept exercise for the python track.

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 Exercise Specifications
• Concept Specifications
• Exercism Formatting and Style Guide
• Exercism Markdown Specification
• Reputation

Goal

This concept exercise 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 this concept exercise.

• 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

• Hints

  For more information on writing hints see hints

  • You can refer to one or more of the resources linked above, or analogous resources from a trusted source. We prefer using links within the Python Docs as the primary go-to, but other resources listed above are also good. Please try to avoid paid or subscription-based links if possible.

Concept Description

Concept file/issue: #2972

• Exercise introduction.md

  For more information, see Exercise introduction.md

  • This should closely relate to or summarize/paraphrase the concept introduction document, but add enough additional information and examples for the student to complete the tasks outlined in this concept exercise.

Test-runner

No changes required to the Python Test Runner at this time.

Representer

No changes required to the Python Representer at this time.

Analyzer

No changes required to the Python Analyzer at this time.

Exercise Metadata - Track

For more information on concept exercises and formatting for the Python track config.json , please see concept exercise metadata. The track config.json file can be found in the root of the Python repo.

You can use the below for the exercise UUID. You can also generate a new one via exercism configlet, uuidgenerator.net, or any other favorite method. The UUID must be a valid V4 UUID.

• Exercise UUID : df9adab4-d428-4774-bfd1-54fefe8c9ae7
• concepts should be filled in from the Concepts section in this issue
• prerequisites should be filled in from the Prerequisites section in this issue

Exercise Metadata Files Under .meta/config.json

For more information on exercise .meta/ files and formatting, see concept exercise metadata files

• .meta/config.json - see this link for the fields and formatting of this file.
• .meta/design.md - see this link for the formatting of this file. Please use the Goal, Learning Objectives,Concepts, Prerequisites and , Out of Scope sections from this issue.

Implementation Notes

• Code in the .meta/examplar.py file should only use syntax & concepts introduced in this exercise or one of its prerequisite exercises.
  Please do not use comprehensions, generator expressions, or other syntax not previously covered. Please also follow PEP8 guidelines.
• In General, tests should be written using unittest.TestCase and the test file should be named <EXERCISE-NAME>_test.py.
• While we do use PyTest as our test runner and for some implementation tests, please check with a maintainer before using a PyTest test method, fixture, or feature.
• 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.

[github-actions]

This issue has been automatically marked as abandoned 🏚 because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[BethanyG]

Currently being worked on in issue #2960.

[BethanyG]

Closing for re-write.