Jim Downing

; Comments

; Obligatory
(println "Hello, JISCRIans!")

; Numbers
25
1.0
22/7

; Strings
"eggs"

; Keywords evaluate to themselves
:this
:that

; Everything else is a "symbol", and represents something else
;
; Lists, by default evaluate as function calls
(+ 5 5)
; N.B. + is not an operator, just a symbol that represents a function
; use ' to prevent evaluation
'("pig" "cow" "aufschnitt")

; Vectors
[1 2 3 4 5]
["eggs" "bacon" "black pudding"]

; Maps (commas are considered to be whitespace)
{"fred" 5, "bill" 10}
; Keywords useful here, and used to define structs
{:id 3, :name "Jack"}
; Maps are functions of their keys, and keywords are functions of any map
(:name {:id 3, :name "Jack"})
({:id 3, :name "Jack"} :id)

; Sets
#{"this" "that" "the other"}
#{"this" "that" "the other" "this"}

; You've now seen pretty much all of the syntax

; Defining things (creating a symbol to refer to them)
(def jack {:id 3 :name "Jack"})
(println jack)
(:name jack)

; Functions
(fn [person]
   (:name person))
((fn [person]
   (:name person)) jack)


(defn get-name [person]
   (:name person))
(get-name jack)

; Java interop
(def sb (StringBuilder. "Quo Vadis?"))
(.reverse sb)
; or
(. sb reverse)
; Chaining methods with ..
(.. sb reverse toString toUpperCase)

(doto (new java.util.HashMap)
    (.put "a" 1)
    (.put "b" 2))


; Exception handling
(def f (java.io.File. "not there"))
(try
    (java.io.FileInputStream. f)
    (catch java.io.FileNotFoundException _ (println "Didn't work!")))