Resources for Learning Clojure?

Question

I primarily program in D nowadays and my second favorite language is Python. I've decided I want to learn Clojure to broaden my horizons to a language that's more functional flavored and designed even more around metaprogramming than D or Python. What are some good (ideally free, but this is not a hard requirement) learning materials for someone with my background:

1. I'm an experienced programmer in more imperative languages. I don't want something that tries to teach me "how to program" rather than just the language.

2. I grok and regularly use some functional flavored constructs (map, reduce/fold, lambda functions, list comprehensions, closures) but tend to think of these as convenience features rather than fundamental primitives.

3. I absolutely love metaprogramming and it's the main reason I care about Clojure. Ideally the learning material should treat macros/metaprogramming as a fundamental part of the language, not an "advanced" feature.

4. I don't care at all about theoretical purity. (For example, despite my interest in Clojure I have zero desire to learn Haskell.) I want learning material with a very practical "getting things done" style.

5. Lisp-style S-expressions and programming mostly without mutable state still seem weird to me, though I'm willing to try to get used to these.

Bottom line: Ideally I want a tutorial that assumes plenty of prior knowledge about programming in general and dives right into the unusual parts of Clojure's syntax and semantics, what cool/unusual things Clojure can do, and how to do them.

Answer 1

Mark Volkmann wrote an online article in 2009. It is very thorough, and garnered positive feedback from the Clojure community. It looks like it has been kept up-to-date.

(Disclosure: Mark is a friend and former colleague.)

Answer 2

You might want to check out Brian Marick's recent three part series on how to do TDD in Clojure (he works through Conway's Game of Life):

http://www.exampler.com/blog/2010/06/10/tdd-in-clojure-a-sketch-part-1/

Answer 3

Since you are extremely interested in macros, here is the best Clojure macro tutorial I've come across.

Answer 4

I would recommend starting with one of Rich Hickey's videos. You can find them on clojure.blip.tv. "Clojure for Java Programmers" is a really good intro.

If you're willing to shell out a little bit of cash either "Joy of Clojure" or "Clojure in Action" from Manning Books are excellent.

You can also check out the question http://stackoverflow.com/questions/599519/which-tutorial-on-clojure-is-best for some more resources.

Answer 5

Adding this as a new answer since its been quite some time since my original answer.

I've started an open source website where you can solve interactive fill-in-the-blank Clojure problems. It should be perfect for someone with your background. We've had a lot of great feedback so far, and the project has a lot of active contributors. The one thing you will probably miss, is that our site doesn't have a lot of metaprogramming problems right now. This is due to restrictions with the sandbox we are using to execute code.

• http://4clojure.com/