marklarr

// Regex 

import Foundation

operator infix =~ {}

@infix func =~ (str: String, pattern: String) -> Bool {
    var error: NSError?
    let regex = NSRegularExpression.regularExpressionWithPattern(pattern, options: nil, error: &error)
    if (error) { return false }

orendon

# add ssh key on remote server

cat ~/.ssh/id_rsa.pub | ssh user@server.com 'cat >> .ssh/authorized_keys'

teropa

Tutorials

• The best tutorials are in the introductory books. See below.
• Getting Started with Clojure - A detailed tutorial on getting a modern (as of Jan 2013) Clojure workflow going.
  • Emacs Live is a nice development environment based on Emacs.
• Understanding The Clojure Development Ecosystem
• Clojure Docs Site is a community-driven doc site with good tutorials, and reference material going somewhat deeper than individual API docs.
• Functional Programming for the Rest of Us is a classic introduction to functional thinking
• [A comprehensive article on namespaces and different ways of requiring them](http://blog.8thlight.com/colin-jones/2010/12/05/clojure-libs-and-namespaces-require-use-import-and-ns.

daniel-beard

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        //background processing goes here
        dispatch_async(dispatch_get_main_queue(), ^{
                //update UI here
        });
});

richhickey

(defmacro test->
  "Takes an expression and a set of test/form pairs. Threads expr (via ->)
  through each form for which the corresponding test expression (not threaded) is true."
  [expr
  & clauses]
  (assert (even? (count clauses)))
  (let [g (gensym)
        pstep (fn [[test step]] `(if ~test (-> ~g ~step) ~g))]
    `(let [~g ~expr
           ~@(interleave (repeat g) (map pstep (partition 2 clauses)))]

fogus

;; This defines the event stream, in this case just a series of numbers,
;; a new one produced each second
(defn timer []
  (lazy-seq
    (do
      (Thread/sleep 1000)
      (cons (System/nanoTime) (timer)))))

;; We can see some events (this takes a couple seconds to complete):
(take 3 (timer))

samaaron

(ns ormclj.pg
  (:require [clojure.java.jdbc :as sql]))

(defn pg-db
  [hostname port db-name user passwd]
  {:classname   "org.postgresql.Driver"
   :subprotocol "postgresql"
   :subname     (str "//" hostname ":" port "/" db-name)
   :user        user
   :password    passwd})

fogus

(ns lisp-ch1)

(def self-evaluating?
  (some-fn number? string? char?
           true? false? vector?))

(defn -atom? [s]
  (or (self-evaluating? s)
      (symbol? s)))

fogus

Latency Comparison Numbers
--------------------------
L1 cache reference                            0.5 ns
Branch mispredict                             5   ns
L2 cache reference                            7   ns             14x L1 cache
Mutex lock/unlock                            25   ns
Main memory reference                       100   ns             20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy              3,000   ns
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD