O’Reilly has just published a new book on Clojure, this time from the “cookbook” series. The book includes over 150 practical recipes on doing some common things in Clojure. Each recipe is self-contained and usually very small.
It starts with a detailed walkthrough of primitive and collection manipulations. Then it includes recipes on basic development tasks (REPL, using docs, running programs etc.), I/O, databases (two recipes on SQL, one for each of a handful of NoSQL databases, plus quite a few on Datomic), web applications with Ring, performance optimization, distributed computing (mostly Cascalog, some Storm) and testing.
In my opinion the book is very uneven. It’s very detailed about the primitives and basic collections, but at the same time it doesn’t do justice to state management (atoms, refs, agents) or concurrency. Yet it has two chapters on building a red-black tree. It is very detailed about Datomic, but barely scratches the surface of much more common tools like core.async, core.logic or core.match. It does not include anything about graphics or ClojureScript.
In short, it sometimes pays much attention to some uncommon problems or tools, while giving too little information on more popular pieces. I think the target audience is somewhere around intermediate. I don’t think it’s a good way to get started with the language, but it is a decent, handy survey of some areas of the landscape.