advent-8.clj

(ns advent.a8
  (:require [clojure.string :as str]
            [instaparse.core :as insta]))

(def parser (insta/parser (slurp "a8.bnf")))

(def lines (str/split-lines (slurp "a8.txt")))

(defn nlits [l] (count (re-seq #"[^\s]" l)))

(defn nchars [l]
  (->> (insta/parse parser l)
       flatten
       (filter #(= :char %))
       count))

(apply + (for [l lines] (- (nlits l) (nchars l))))

;; This is so cheap!
(def vals {:dq 2
           :hex 3
           :esq 4
           :ess 4
           :char 0
           :c 1})

(defn ncodes [l]
  (->> (insta/parse parser l)
       flatten
       (filter keyword?)
       rest
       (map vals)
       (reduce +)
       (+ 2)))

(apply + (for [l lines] (- (ncodes l) (nlits l))))