;;
;; Generic utility functions.
;;

;; Return first item of sequence, or null if it is empty.
(defn first-or-null (seq) (if (empty? seq) null (first seq)))

;; Split string by whitespace, removing empty strings.
(defn split-ws (s) (re-split "/[\\s]+/" s))

;; Split string by whitespace into first and rest.
;; Useful for parsing a string for command name and arguments.
(defn str-first-rest (s)
  (let (words (split-ws s))
    [(first-or-null words) (tail words)]))