do.fnl

(fn ripairs [list]
  (var index (length list))
  (fn []
    (match index
      0 nil
      _ (do
          (let [ret (. list index)]
            (set index (- index 1))
            (values index ret))))))

(fn reduce [list start reducer]
  (var acc start)
  (each [_ x (ipairs list)]
    (set acc (reducer acc x)))
  acc)

(fn mapFile [filename descriptor mapFn]
  (match (io.open filename descriptor)
    f (do
        (mapFn f)
        (f:close))
    (nil err-msg) (print "Could not open file:" err-msg)))

(fn file_to_table [filename descriptor mapFn]
  (let [tasks {}]
    (mapFile filename :r
             (fn [f]
               (each [line (f:lines)]
                 (table.insert tasks line))))
    tasks))

(fn trim [str]
  (str:gsub "^%s*(.-)%s*$" "%1"))

(let [[command] arg
      filename (.. (os.getenv :HOME) :/bulb.do)]
  (match command
    :push (do
            (table.remove arg 1)
            (let [task (trim (reduce arg ""
                                     (fn [acc x]
                                       (.. acc " " x))))]
              (print :Pushing task)
              (mapFile filename :a
                       (fn [f]
                         (f:write (.. task "\n"))))))
    :pop (let [tasks {}]
           (mapFile filename :r
                    (fn [f]
                      (each [line (f:lines)]
                        (table.insert tasks line))))
           (print "Done:" (table.remove tasks))
           (if (= 0 (length tasks))
               (print "You're all done!")
               (do
                 (print "Onto:" (. tasks (length tasks)))
                 (mapFile filename :w
                          (fn [f]
                            (each [_ task (ipairs tasks)]
                              (f:write (.. task "\n"))))))))
    :peek (let [tasks (file_to_table filename :r)]
            (let [(_ task) ((ripairs tasks))]
              (print task)))
    :print (let [tasks (file_to_table filename :r)]
             (each [i task (ripairs tasks)]
               (if (= i (- (length tasks) 1))
                   (print "> " task)
                   (print " " task))))
    :clear (mapFile filename :w (fn [f]
                                  (f:write "")))
    _ (print "push [task] pushes the task onto the task stack
pop removes the top task and displays the next one
print lists tasks in order
peek displays your current task
clear removes all tasks")))