All About PSKoans

It's been a handful of months since I started working on the PSKoans module, so I thought I'd take the time to set down the story behind the PSKoans module. It borrows from some koans modules from other languages, and the concept of koans as a programming tool seems to originate from a Ruby project — although at least a handful of other languages now have koan libraries available for learners.

The concept of kōans was first introduced to me when I first decided to learn how to code in F#. Initially, I struggled quite a bit. For those of you who mightn't be familiar with it, it's a bit of an unusual language that aims to bring functional language features into a .NET family language. This places it in a bit of a strange in-between, where many of the libraries are heavily object-oriented, and yet the language itself is quite clearly built for more functional constructs.

Whilst searching for learning resources, I stumbled across Chris Marinos' F# Koans, which (like other koans projects) aim to teach you F# by presenting you with a series of failing assertions, and guiding you towards fixing them, teaching you the logic behind how it works. These in turn are inspired by EdgeCase's Ruby Koans, and the readme there has further links and information as the origins of the concept itself.

First, Some Definitions

You could say the simplest definition of a kōan is "a logical contradiction." The term is old, dating back to Zen Buddhist monks, who would be instructed to meditate upon logical contradictions until they could arrive at a purely intuitive understanding of a concept being studied, rather than simply reasoning logically. It is often written simply as koan, mainly because the accented O character can be a bit tricky to type on English keyboards.

For programming purposes, a koan usually is framed as an assertion which is initially written in a 'failing' state. A contradiction. Something simple like 1 + 1 | Should -Be 3 (at least, if you write it in Pester syntax) should give you the general idea. In actuality, many koans projects opt to define a custom blank function to represent a space to be filled in; in PSKoans I have a function named Get-Blank which uses __ as its alias, and a similar idea is used in Chris Marinos' F# Koans.

This is used to create an assertion that will always fail the first time around, and often some interaction framework is used as an in-between to help guide the pupil to where to look in the error message and how to find the issue and resolve it For example:

Describe 'Addition' {
    It 'is basic arithmetic' {
        __ | Should -Be ( 5 + 1 )

Executing this in PowerShell (with PSKoans installed, or a simple return $null function aliasing the __ command call) will result in the following output:

+ Describing Addition
-   [-] is basic arithmetic 3.9s
-     Expected 6, but got $null.
-     3:         __ | Should -Be ( 5 + 1 )

Pretty straightforward; tells you what's wrong, and where it needs to be fixed.

Closing the Gap

Up until recently, a majority of PowerShell learning materials fit into the following categories:

  • Books
  • Talks
  • Blog Posts
  • Documentation

These are all wonderful ways to learn and expand on what you know. However, they lack a certain something that I would have loved to have when I was learning the ropes myself — that extra bit of interactivity. For me, learning to code from a book has always been a doomed prospect. There's something incredibly disconnecting about the code being on a printed (or even digital) book page; if you ever want to try something out, you have to write everything out all at once, and if you're not familiar with the language, chances are you'll mess it up and not even begin to know where you went wrong. Books are great for teaching concepts, but for me they miss by a large margin when trying to convey or really impress the practicality of the language, or even the depth of its usefulness.

Talks have a similar issue, I fear; they're fantastic for opening up your breadth of knowledge and showing you some really cool stuff you mightn't see or hear about otherwise, but they fall quite flat when you don't have the basics down and can't really follow what's going on quite yet.

And blog posts and documentation can often be far too dry to really spark those learning moments. Not that they're bad, of course. They have their place, as everything else I listed does — and I'm sure I missed a few methods, as well — but there's a gap where it really truly pays to have some form of interactive experience, and I hope that that's where PSKoans can come in and really shine. My wife likens it to a game — we set the challenges, and you need to solve them one by one or in bulk if you prefer, and we can give you feedback of how you're doing, where you're going wrong, and (down the development road, anyway) potentially even eventually some suggestions of how to proceed in areas you might get stuck.

Taking the Plunge

I'm sure many of my readers are probably tending towards the more advanced, but it's been my own experience that we tend to have little holes in our knowledge even of the more basic things. In fact, as I create the koans for a particular topic I often learn new things about that very topic while I'm writing them! So, if you've not yet found the time to knock out a few koans and see why I keep suggesting new folks try it, I can only encourage you to give it a shot — you may well learn something from the experience.

If nothing else, perhaps you'll gain enough familiarity to simply be able to provide a gentle recommendation for those learning PowerShell. I've been chatting to a few people about their possible application in a more controlled group classroom or training-type setting as well, and Thomas Rayner has already begun teaching some of his coworkers using PSKoans as one of the primary tools. His initial results are encouraging, but as with any stress test I tend to miss the occasional oddity until someone stumbles across it. It's very hard to properly review your own writings, after all, even when they are in PowerShell — but I try my best!

Installing the Module

PSKoans is available from the PowerShell gallery, or the Github page, so you can install it anywhere you have a PowerShell 5.1 or PowerShell Core engine available. It's designed to be fairly easy to work with, but it does require a recent version of Pester to be installed, so make sure you have that down and then it's simply an Install-Module PSKoans away! If you have any issues or concerns, feel free to leave an issue on the Github and I'll get back to you shortly — or if it's urgent, you can reach me on the PowerShell Discord server.