Vít Kotačka sw-samuraj

sw-samuraj / blog-concurrency-var-global.clj

Last active March 23, 2017 21:37

An example of Var re-binding (future/global).

	(future (def future-var "future var"))

	future-var
	;; -> "future var"

sw-samuraj / blog-concurrency-var-dynamic.clj

Last active March 25, 2017 17:41

An example of Var re-binding (dynamic).

	(def ^:dynamic dynamic-var "dynamic var")

	dynamic-var
	;; -> "dynamic var"

	(def re-binded-var
	(binding [dynamic-var "re-binded var"] dynamic-var))

	re-binded-var
	;; -> "re-binded var"

sw-samuraj / blog-concurrency-var-defn.clj

Last active March 20, 2017 21:06

An example of re-binding of the Var containing a composite function.

	(defn cube [x] (Math/pow x 3))

	(defn cube-root [x] (Math/pow x 1/3))

	(defn ^:dynamic prettify [x] (Math/round x))

	(defn compute [] (prettify (cube-root (cube 42))))

	(compute)
	;; -> 42

sw-samuraj / blog-concurrency-var-static.clj

Last active March 25, 2017 17:43

An example of Var re-binding (static).

	(def static-var "static var")

	static-var
	;; -> "static var"

	(binding [static-var "re-binded var"] static-var)
	;; -> IllegalStateException Can't dynamically bind non-dynamic var:
	;; user/static-var clojure.lang.Var.pushThreadBindings (Var.java:320)

sw-samuraj / blog-catalan.clj

Last active March 18, 2017 16:09

Counts a Catalan number through a binomial coefficient.

	(defn factorial [n]
	"Counts a factorial."
	(reduce *' (range 1 (inc n))))

	(defn binomial [n k]
	"Counts a binomial coefficient."
	(/ (factorial n)
	(*' (factorial k)
	(factorial (- n k)))))

sw-samuraj / blog-catalan-recur.clj

Created March 18, 2017 14:26

Counts a Catalan number through recursion.

	(defn catalan [n]
	"Counts a Catalan number by recursion."
	(loop [cnt n acc 1]
	(if (zero? cnt)
	acc
	(recur (dec cnt)
	(* acc (- 4 (/ 6 (inc cnt))))))))

sw-samuraj / blog-map-reduce.clj

Last active March 10, 2017 17:11

Map-reduce snippet for a blog post.

	(ns blog-map-reduce.core
	(:import java.security.MessageDigest))

	(defn digest [string]
	"Returns a SHA-1 digest of the given string."
	(.digest (MessageDigest/getInstance "SHA-1")
	(.getBytes string)))

	(defn hex [bt]
	"Returns a hexadecimal value of the given byte."