Advent Of Code [Puzzle 1](https://adventofcode.com/2019/day/1) in [Fennel](https://fennel-lang.org/)

advent2019-1.fnl

(fn mass->fuel [mass]
  (-> (tonumber mass) (/ 3) (math.floor) (- 2)))

(let [file (io.open "1.data" "r")
      file-contents (file:read "*a")
      mods (string.gmatch file-contents "%d+")]
  (var total-fuel 0)
  (each [mass mods]
    (let [fuel (mass->fuel mass)]
      (set total-fuel (+ total-fuel fuel))
      (var rest-fuel fuel)
      (while (> rest-fuel 0)
        (do
          (set rest-fuel (mass->fuel rest-fuel))
          (if (> rest-fuel 0)
            (set total-fuel (+ total-fuel rest-fuel)))))))
  (print total-fuel))