Values and collections

Numbers and strings are values. Square brackets construct a persistent Vec; map literals use braces, and set literals use #{...}. Updating a collection returns a value; an existing holder still sees its old contents. mapv eagerly returns a vector, while map returns a sequence. A sequence and a vector have different types; use vec to convert. Try expressions in fibc repl. Next: functions.

(ns main (:use fib.core fib.seq fib.coll))
(defun main () -> i64
  (let ((xs [1 2 3]) (squares (mapv (fn (x: i64) (* x x)) xs)))
    (do (println squares) (println (reduce + 0 squares)) 0)))

[1 4 9]
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