This README is an attempt to organize the materials I've been using to study functional programming and Clojure more specifically.
Tutorial - Clojure Lab
A Clojure workshop by Cognitec, free and open-source. Live (in-browser) tutorials running in your local machine. Lots of small exercises focusing on the language fundamentals. I really liked it, but half-way through I just started reading the theory and not doing the exercises. Actually I felt I needed more theory before digging deeper in exercises...
The problem with this workshop is that it was built around the idea of a more or less complete reference. It gets boring real quick... People starting on Clojure don't need to know all there is about a subject right at the start. For example, in the chapter about functions we're presented with Java interop, gotchas, and the anonymous function syntax. They're very lightly touched, but even then, it would've been better if I was presented with a single way to define a function and worked with that for a while.
Great introduction to Clojure and it's free to read online. It gives you a great sense of accomplishment and confidence in the beginning, which is so important. It introduces Emacs for Clojure development, but I'd recommend sticking with your preferred editor for a while. I mainly use Vim for software development, and it's been working great for Clojure too.
I found myself usually skipping the chapter tutorials (almost every chapter has one). I don't like tutorials for learning unless I'm at the very very beginning. I recognize this varies a lot between people with different backgrounds.
Book - Applied Clojure
I really enjoyed this book and highly recommend it after you've been through the basics and feel confortable with the language. It was writen for people in the middle stage of learning Clojure. After reading and practing with this book I started to understand how things fit together in real world libraries. That's also where I started diving into GitHub repos, macros source code, etc.
I specially liked examples and discussions around state and concurrency.
Community-driven exercises - Exercism
Excellent resource for solving problems while learning about Clojure's core functions and idioms. You can also see how others solved the same problem, so you also get a little bit of feedback, like you weren't learning all by yourself :) It also has similar problems in other languages, so if you know Javascript, you can solve a problem in Javascript and Clojure.
The key to the Exercism success is that you start with nothing but already writen unit tests, then it's your job to derive solutions from tests. It increases the chances that you'll solve the problem, not give up and thus learn some things.
YouTube Channel ClojureTV
Seriously, this has been an endless source of material for learning in general. High-quality talks about a wide range of subjects, mostly Clojure related of course. I have yet to build a playlist with the best ones!
YouTube Paid Channel - Clojure Tutorials, by Timothy Baldridge
Great channel and worth the price to me. This channel is more focused on the intermediary Clojure developer willing to grasp more advanced concepts, or just learning Clojure in even more detail. You can experiment for 14 days, and after that you have to pay to watch non-public videos from the channel.
It doesn't matter your proficiency with functional programming and Clojure, you do need to be up-to-date with the latest discussions, libraries, etc involving the Clojure community. A curated newsletter also keeps me motivated and helps me find next topics for improvement.
PurelyFunctional.tv is my number one newsletter at the moment. Eric Normand focuses most of his content on higher-level discussions, legendary talks, papers (I really like his Computer Science oriented newsletters). Usually great food for thought beyond just Clojure as a language. He also runs Clojure workshops and offers on-line courses. What I don't like is the amount of personal marketing I get in my inbox, but that's the trade-off.
The REPL, a weekly Clojure newsletter, by Daniel Compton.
I feel productive in Clojure with Vim plus two plugins: vim-fireplace and vim-sexp-mappings-for-regular-people. It may not be the perfect playground for Clojure, but it's miles better than nothing.
Although the REPL is an invaluable tool, being able to watch tests in a tmux split works wonders for me. clojure-expectations was my test library of choice and has been awesome since the beginning. Super low learning curve for beginners, and yet very powerful for more advanced usages.
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Rewriting code from one language to another is always a challenge and forces you to think about language idioms, even more if the original was writen in Ruby, Java, C# and the like. I did attempt to rewrite the GildedRose Refactoring Kata to Clojure and refactor it. Great feeling of accomplishment in the beginning!
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When learning something completely new, people need that feeling of discovery, so it's important to introduce new concepts on demand.
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Get used to read the Clojure docs. Avoid your Stack Overflow instincts. When starting to learn a language it's super important to get the fundamentals right. Two sources come to mind: Clojure Docs (official documentation + lots of examples), and Clojure lang reference (good reading for understanding Clojure in more detail, but can be a little too dense for starters).
- Lambda Island, Clojure and ClojureScript screencasts. Free trial.
- Jay Fields' Thoughts, author of the clojure-expectations library and I've read some pretty good things about Clojure in his blog.
- Ruby Quiz - Excellent list of challenging problems. Try to solve some of them in Clojure!
- Trivial examples of transducers - What are transducers and how to use them...? I need more references :)
- Writing Clojure in Vim