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(defn square [x] (* x x))
(meditations
"One may know what they seek by knowing what they do not seek"
(= [true false true] (let [not-a-symbol? (complement symbol?)]
(map not-a-symbol? [:a 'b "c"])))
"Praise and 'complement' may help you separate the wheat from the chaff"
(= [:wheat "wheat" 'wheat]
(let [not-nil? (complement nil?)]
(filter not-nil? [nil :wheat nil "wheat" nil 'wheat nil])))
"Partial functions allow procrastination"
(= 20 (let [multiply-by-5 (partial * 5)]
(multiply-by-5 4)))
"Don't forget: first things first"
(= [:a :b :a :b]
(let [ab-adder (partial concat [:a :b])]
(ab-adder [:a :b])))
"Functions can join forces as one 'composed' function"
(= 25 (let [inc-and-square (comp square inc)]
(inc-and-square 4)))
"Have a go on a double dec-er"
(= 8 (let [double-dec (comp dec dec)]
(double-dec 10)))
"Be careful about the order in which you mix your functions"
(= 99 (let [square-and-dec (comp dec square)]
(square-and-dec 10))))