Basics

{
"fizz" true
:bugs
false
[1 2 3] {:do "re"}
}

(first [1 2 3])
; => 1
(first '(1 2 3))

(first [1 2 3])
; => 1
(first '(1 2 3))
; => 1

(first [1 2 3])
; => 1
(first '(1 2 3))
; => 1
(first #{1 2 3})

(first [1 2 3])
; => 1
(first '(1 2 3))
; => 1
(first #{1 2 3})
; => 2

(first [1 2 3])
; => 1
(first '(1 2 3))
; => 1
(first #{1 2 3})
; => 2
(first {:one 1 :two 2})

(first [1 2 3])
; => 1
(first '(1 2 3))
; => 1
(first #{1 2 3})
; => 2
(first {:one 1 :two 2})
; => [:two 2]

(range 10)
;=> (0 1 2 3 4 5 6 7 8 9)

(take 5 (range))
; => (0 1 2 3 4)

(defn fib [a b]
(cons a (lazy-seq (fib b (+ b a)))))

(fn [name]
(println "Hello " name))

(def greet
(fn [name]
(println "Hello " name)))

(def greet [name]
fn
(println "Hello " name))

(map inc [1 5 9])

=> [2 6 10]

(defn create-incrementor [increment-by]
(fn [number]
(+ number increment-by)))

(fn [number]
(map (create-incrementor 7) [1 5 9])

(fn [number]
(map (create-incrementor 7) [1 5 9])
=> [8 12 16]

AUTOMATED TESTS
(fact (split "a/b/c" #"/")
=> ["a" "b" "c"])
(tabular
(fact "The rules of Conway's life"
(alive? ?cell-status ?neighbor-count) => ?expected)
?cell-status
:alive
:alive
:alive
:alive

?neighbor-count
1
2
3
4

?expected
false
true
true
false

:dead
:dead
:dead

2
3
4

false
true
false)

SQL
(defdb prod
(postgres {:db "korma"
:user "db"
:password "dbpass"}))

(defentity address)
(defentity user
(has-one address))

(select user
(with address)
(fields :firstName :lastName :address.state)
(where {:email "korma@sqlkorma.com"}))

JSON
(ns examples.json
(:use cheshire.core))
(generate-string {:foo "bar" :baz 5})
=> {“foo”: “bar”, “baz”: 5}
(parse-string "{"foo":"bar"}")
=> {"foo" "bar"}

XML PARSING
(ns examples.xml
(:use clojure.xml)
(:import java.io.File))
(def xml-doc
(parse (File. "calendar.xml")))
(get-in xml-doc [:content 1 :content 0 :content])
=> [“Rover’s birthday”]

HTML
(ns examples.templating
(:use hiccup.core)

(html [:span {:class "foo"} "bar"])
=> "<span class="foo">bar</span>"

(html [:ul
(for [x (range 1 4)]
[:li x])])
=> "<ul><li>1</li><li>2</li><li>3</li></ul>"

WEB
(ns hello-world
(:use compojure.core)
(:require [compojure.route :as route]))
(defroutes app
(GET "/" []
"<h1>Hello World</h1>")
(route/not-found
"<h1>Page not found</h1>"))

GUI
(ns seesaw.test.examples.slider
  (:use [seesaw core color border] seesaw.test.examples.example))
(defn make-frame []
  (frame
    :title "Slider Example"
    :content
      (horizontal-panel :items [
        (vertical-panel :items [
          "<html>Slide the sliders to change<br>the color to the right</html>"
          (slider :id :red
:min 0 :max 255)
          (slider :id :green :min 0 :max 255)
          (slider :id :blue :min 0 :max 255)])
        (canvas :id :canvas :border (line-border) :size [200 :by 200])])))
(defn update-color [root]
  (let [{:keys [red green blue]} (value root)]
    (config! (select root [:#canvas]) :background (color red green blue))))
(defexample []
  (let [root (make-frame)]
    (listen (map #(select root [%]) [:#red :#green :#blue]) :change
            (fn [e] (update-color root)))
    root))

number = 1

while number < 20
if number % 3 == 0 && number % 5 == 0
puts "fizzbuzz"
elsif number % 3 == 0
puts "fizz"
puts "buzz"
else
puts number
end

number = number + 1
end

for number in 1..20
if number % 3 == 0 && number % 5 == 0
puts "fizzbuzz"
puts "fizz"
puts "buzz"
else
puts number
end
end

numbers = (0..20).map do |number|
if number % 3 == 0 && number % 5 == 0
"fizzbuzz"
"fizz"
"buzz"
else
number
end
end

puts numbers

(defn divisible-by? [divisor number]
(= 0 (mod number divisor)))

(defn fizz-buzzify [number]
(cond
(divisible-by? 15 number) "fizzbuzz"
(divisible-by? 3 number) "fizz"
(divisible-by? 5 number) "buzz"
:else number))

(def fizz-buzz (map fizz-buzzify (range)))

(mapv println (take 100 fizz-buzz))

IMPLEMENTATIONS
Clojure (JVM)
ClojureScript
ClojureCLR
clojure-py
clojure-scheme

Basics

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