language.counting

(ns language.counting)

checking math still works

(= (+ 2 2) 4)

addition is associative

(+ 1 (+ 2 (+ 3 (+ 4 5))))

and clojure knows this

(+ 1 2 3 4 5)

apply macro can use a collection as args to a function like a splice in some languages

(apply + [1 2 3 4 5])

oh functional programmers do love themselves some reductions!

(reduce + [1 2 3 4 5])

and you can generate the sequence too instead of write it out

(reduce + (range 1 6))

this is basically the trimmed down implementation of what actually happens above

(loop [[x & xs] (range 1 6) sum 0]
    (if (empty? xs) sum
        (recur xs (+ sum x))))