Clojure Instaparse examples

instaparse.clj

;; "human" date/time format parsing

(def human-time-parser
  (insta/parser
    "S = H (':' M)? ' '? P? (' ' Z)?
     H = #'[1-9]' | #'1[0-2]'
     M = #'0[0-9]' | #'[1-5][0-9]'
     P = AM | PM
     AM = 'A' 'M'?
     PM = 'P' 'M'?
     Z = 'EST' | 'ET' | 'CST' | 'CT' | 'PST' | 'PT' | 'MST' | 'MT'"
    :string-ci true))

(defn interpret-parse [tree]
  (reduce (fn [acc elem]
            (if (vector? elem)
              (let [[tag & vals] elem]
                (case tag
                  :H (assoc acc :hour (Integer/parseInt (first vals)))
                  :M (assoc acc :minute (Integer/parseInt (first vals)))
                  :P (assoc acc :period (ffirst vals))
                  :Z (assoc acc :timezone (first vals))
                  acc))
              acc))
          {}
          tree))

(defn parse->date-time [date {:keys [hour minute period timezone]
                              :or   {minute 0 period :PM}}]
  (let [hour (case period ;; convert 12- to 24-hour time
               :AM (if (= 12 hour) 0 hour)
               :PM (if (< 0 hour 11)
                     (+ 12 hour)
                     hour))
        tz   (condp #(cs/starts-with? %2 %1) (or timezone "CST")
               "C" (time/time-zone-for-id "US/Central")
               "E" (time/time-zone-for-id "US/Eastern")
               "P" (time/time-zone-for-id "US/Pacific")
               "M" (time/time-zone-for-id "US/Mountain"))]
    (-> (time/with-time-at-start-of-day date)
        (.withHourOfDay hour)
        (.withMinuteOfHour minute)
        (time/from-time-zone tz))))

(def test-inputs
  ["10:01 am est"
   "12 am"
   "12 P CST"
   "1am"
   "2p PT"
   "11:11p"
   "1:00"])

(sequence
  (comp
    (map human-time-parser)
    (map interpret-parse)
    (map #(parse->date-time (time/now) %)))
  test-inputs)

;; bowling scores

(def bowling-score-parser
  (insta/parser
    "S = F F F F F F F F F 10TH
     F = OPEN | CLOSED
     OPEN = ROLL ROLL
     CLOSED = STRIKE | SPARE
     10TH = OPEN |
            SPARE (STRIKE | ROLL) |
            STRIKE (SPARE | ROLL ROLL) |
            STRIKE STRIKE (STRIKE | ROLL)
     STRIKE = 'X'
     SPARE = ROLL '/'
     ROLL = PINS | MISS
     PINS = #'[1-9]'
     MISS = '-'"))

(bowling-score-parser "XXXXX6/XX7/XX5")
(bowling-score-parser "XXXXXXXXXXXX")
(bowling-score-parser "XXXXXXXXXX-/")
(bowling-score-parser "XXXXXXXXX--")
(bowling-score-parser "9-9-9-9-9-9-9-9-9-9-")
(bowling-score-parser "X7/9-X-88/-6XXX81")
(bowling-score-parser "X7/9-X-88/-6XX-/X")
(bowling-score-parser "X-/X5-8/9-X811-4/X")
(bowling-score-parser "6271X9-8/XX3572-/X")