If you’re using Emacs, grab clojure-mode.el from technomancy’s Github, which differs from the one in ELPA (I don’t know why, both claim to be version 1.11.5, maybe someone can comment on that?) but includes clojure-fill-docstring which will format docstrings with nice indentation and linewrapping, bound by default to C-c M-q. It will take this: (defn … Read more
(every? f data) [docs] is the same as all(f(x) for x in data). (some f data) [docs] is like any(f(x) for x in data) except that it returns the value of f(x) (which must be truthy), instead of just true. If you want the exact same behaviour as in Python, you can use the identity … Read more
These are the steps I took to set them up without using ELPA. Hope this helps. Get SLIME using MacPorts sudo port -v install slime Get paredit curl -O http://mumble.net/~campbell/emacs/paredit.el Get clojure & clojure-contrib Either using MacPorts sudo port -v install clojure clojure-contrib Or downloading directly curl -O http://build.clojure.org/snapshots/org/clojure/clojure/1.1.0-master-SNAPSHOT/clojure-1.1.0-master-20091202.150145-1.jar curl -O http://build.clojure.org/snapshots/org/clojure/clojure-contrib/1.1.0-master-SNAPSHOT/clojure-contrib-1.1.0-master-20091212.205045-1.jar Get clojure-mode and … Read more
This isn’t specific to noir but one scenario you might want to skip AOT for a given namespace is when deploying your code to a PaaS provider such as heroku. Heroku performs AOT compilation of your code by default so consider this snippet in your server.clj: (db/connect! (System/getenv “DB_URL”)) (defn start [port] (run-jetty app {:port … Read more
To answer you first question: (defn fib ([n] (fib [0 1] n)) ([x, n] (if (< (count x) n) (fib (conj x (+ (last x) (nth x (- (count x) 2)))) n) x))) This type of function definition is called multi-arity function definition. You can learn more about it here: http://clojure.org/functional_programming As for a better … Read more
Docstrings are stored as metadata under the :doc key. This is probably the number 1 most apparent use of metadata. Return and parameter types can be optionally tagged with metadata to improve performance by avoiding the overhead of reflecting on the types at runtime. These are also known as “type hints.” #^String is a type … Read more
According to Joy of Clojure, nil punning with seq is idiomatic: (defn print-seq [s] (when (seq s) (prn (first s)) (recur (rest s)))) “…the use of seq as a terminating condition is the idiomatic way to test whether a sequence is empty. If we tested [in the above example] just s instead of (seq s), … Read more
Clojure STM has 3 big unique features: Implements MVCC snapshot avoiding transactions restarts on read invalidation. Ensures references on read-writes provides a kind of manual control over resource acquisition order. Has explicit commute which reduces retries on commutative writes.
There was a new function added in Clojure 1.6 to support this. clojure.test/test-vars will run one or more test vars with fixtures. I think something like this should work: (clojure.test/test-vars [#’the-ns/the-test])
Some performance problems: The (range 2 20) call is creating a new lazy list of numbers for every increment of i. This is expensive, and is causing lots of unnecessary GC. You are doing a lot of boxing by passing through function calls. Even the (iterate inc 1) is doing boxing / unboxing at every … Read more