(ns language.counting)
checking math still works
(= (+ 2 2) 4)
these bellow are all the same!
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))))
now time for some meta