Running with the devil

This blog has been dormant for quite some time. But I would like to take this oppertunity to promote a special site that has stolen my heart over the last couple of weeks. It is a tool for learning that runs with the devil. The site I’m talking about is exercism.io, to quote their byline:

Crowd-sourced code reviews on daily practice problems.

The site is currently in public beta, but I have not seen any problems with it yet. The idea is that you solve small programming problems in a language of your choice, who get reviewed by your peers. This process can help you reach a solution to the problem that is idiomatic for the language you’re using. This really magnifies your learning of a language. Mainly because you can be enlightened about the blind spots that you have when you’re trying to learn a new language and start with the mindset of the language(s) that you already know. The list of languages that you can use is quite extensive:

• Clojure
• Coffeescript
• Elixir
• Go
• Haskell
• Javascript
• Objective C
• Ocaml
• Perl5
• Python
• Ruby
• Scala

Support for Java, Rust, Erlang, PHP and Common Lisp is comming soon. The exercises come with a Readme that describes the behavior you need to implement and a set of unit tests you can use to check your solution. Retrieving the exercises and submitting your solutions is handled by a small command-line utility named exercism. The exercises I’ve worked on upto now are what I would call bite-sized. A first iteration of an exercise can be produced in 5-15 minutes. So the barrier to entry is really low. This is great for people who want to improve their skills but also want to maintain a work-life balance. The fact that other people take the time to review your work also really motivated me to improve my solutions to the exercises. To put it in other words, having people help you, really makes learning easier and more fun.

A good example of how your code gets refined when following up on other peoples advice is the 9 iterations it took me before I was happy with my solution to the wordcount exercise in Haskell. One of my reviewers was kind enough to point me to a library function that greatly simplified my solution. Furthermore being reminded that Haskell is a lazy language was also great for me because those are the practical details that you hardly ever see in language tutorials.

Another great aspect of exercism is that you can learn to recieve and give feedback, which I think is a critical skill to practice if you want to succeed as a professional software developer. Discussing code in this kind of detail really enforces my view that readibillity of code is more important than terseness, especially when it comes to a language like Haskell. I hope I’ve inspired you to try out exercism and hope your code will soon be running with the devil.