Description
This issue describes how to implement the rich-comparisons
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:
- The features of v3
- The Anatomy of Exercism & The Anatomy of a Language Track
- Concepts & Concept Exercises
- Exercism Formatting and Style Guide
- Exercism Markdown Specification
Watching the following video is also helpful. It is a bit outdated, but is good for describing the general process:
Goal
This concept exercise is meant to teach an understanding/use of rich comparison
methods in python. It should also generally explain how to override the behavior of rich comparison
operators and methods.
Learning objectives
- understanding (and using the concept) that the
==
operator calls the dunder method__eq__()
on a specific object, and uses that object's implementation for comparison. Where no implementation is present, the default__eq__()
from genericobject
is used. - the same applies for operators
<
,<=
,!=
,>=
,>
and correspondents dunder methods__lt__
,__le__
,__ne__
,__ge__
,__gt__
- overriding the default implementation of the
__eq__()
dunder method on a specific object to customize comparison behavior. - overriding the default implementations of the
__lt__
,__le__
,__ne__
,__ge__
,__gt__
dunder methods on a specific object to customize comparison behavior. - the pros and cons of using
functools.total_ordering
to "shortcut" defining all rich comparison methods for a class. - return the singleton
NotImplemented
if the called operation is not implemented
Out of scope
- performance considerations
Concepts
__eq__
,__lt__
,__le__
,__ne__
,__ge__
,__gt__
dunder methods- comparison behavior customization
- operator overload
- dunder methods override
Prerequisites
These are the concepts/concept exercises the student needs to complete/understand before solving this concept exercise.
basics
booleans
classes
class-customization
class-inheritance
class-composition
comparisons
dicts
dict-methods
iteration
lists
list-methods
numbers
operator-overloading
sequences
sets
strings
string-methods
tuples
Resources to refer to
-
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.
-
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.
- The same resources listed in this issue can be used as a starting point for the
Concept Description
Please see the following for more details on these files: concepts & concept exercises
-
Concept
about.md
Concept file/issue: There is currently no issue or files for the concept. They are TBD.
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.
-
Exercise
introduction.md
For more information, see Exercise
introduction.md
- This should also summarize/paraphrase the above document, but with enough 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 :
0fc646ac-667e-4fc9-bdee-9be7d5431987
- 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.