Clojure Crash Course

clojure-ref.md

Clojure Basics Tutorial - Learning for Cambia ADIF Team

Package file into JAR with Leinengen

• lein uberjar
• Execute with: java -jar target/uberjar/<your-code.jar>

Clojure recognizes two kinds of structures:

1. Literal representations of data structs
2. Operations

Variables: immutable and assigned types

• (def randVar 10) : declare a long
• (def aDouble 1.233) : double
• (type false) | (type true) : Bool
• (nil) : Check no val

Functions: Defined by 5 parts

1. defn
2. Function name
3. Docstring describing function
4. Parameters in brackets
5. Function body

(defn -main
  "These are comments"
  [& args]
  (println "Hello World"))

Operations

(str "Hi" "There" "Dude") : Concatenate (pos? 15) : Check positive (even? 26) (odd? 13) (number? num)

Control Flow: if, do, when

conditionals

(if boolean-form
  then-form
  optional-else-form)

do operator wraps up multiple forms in parens and runs each

(if true
 (do (println "Do first")
             "Then this")
 (do (println "Else...")
           ("Do these"))

Data Structures

Maps

{:first-name "Charlie"
 :last-name "MacDennis"}

Hash-Maps : Another way to declare

(hash-map :a 1 :b 2)

(get {:a 0 :b 1} :b)
; => 1

Vectors

[3 2 1]
(vector 3 2 1)

Lists

'(1 2 3 4)

Sets: Hash sets and Sorted sets

#{"kurt" 30 :icicle}
(hash-set 1 1 2 2)