why's poignant guide to ruby in clojure - chapter 4

wpgtr-ch4.clj

; ex. 1:
(def blue-crystal 1)
(def leaf-tender 5)

; ex. 2:
(catch-a-star pipe)

; ex. 3:
(def captive-star (catch-a-star pipe))

; ex. 4:
(def star-monkey (attach ratchet captive-monkey captive-star))

; ex. 5:
(def star-monkey 
  (hot-glue deco-hand-frog
            (attach ratchet captive-monkey (catch-a-star pipe))))

; ex. 6:
(def plastic-cup nil)

; ex. 7:
(if plastic-cup "Plastic cup is on the up 'n' up!")

; ex. 8:
(if-not plastic-cup "Plastic cup is on the down low.")

; ex. 9:
(if plastic-cup "Yeah, plastic cup is up again!")
(if-not plastic-cup "Hardly. It's down.")

; ex. 10:
(if (and plastic-cup (not glass-cup)) 
  "We're using plastic 'cause we don't have glass.")

; ex. 11:
(def approaching-guy true)

; ex. 12:
(if (= approaching-guy true) "That necklace is classic.")

; ex. 13:
(if (= approaching-guy false) "Get in here, you conniving devil.")

; ex. 14:
(= approaching-guy true)

; ex. 15:
(if (= nil true) "This will never see realization.")

; ex. 16:
(def at-hotel true)
(def email (if at-hotel "why@hotelambrose.com" "why@drnhowardcham.com"))

; ex. 17:
(def email (let [address "why"] (str address "@hotelambrose" ".com")))

; ex. 18:
(cond 
  (nil? at-hotel) "No clue if he's in the hotel."
  at-hotel        "Definitely in."
  (not at-hotel)  "He's out."
  :else           "The system is on the freee-itz.")

; ex. 19:
(print "Type and be diabolical: ")
(def idea-backwards (clojure.string/reverse (read-line)))

; ex. 20: 
(def idea-backwards (clojure.string/reverse (.toUpperCase (read-line))))

; ex. 21:
(def code-words
  {"starmonkeys" "Phil and Pete, those prickly chancellors of the New Reich",
   "catapult" "chucky go-go", "firebomb" "Heat-Assisted Living",
   "Nigeria" "Ny and Jerry's Dry Cleaning (with Donuts)",
   "Put the kabosh on" "Put the cable box on"})

; ex. 22:
(require '[clojure.string :as str])
(use 'clojure.java.io)

(print "Enter your new idea: ")
(def idea (read-line))
(def safe-idea
  (reduce (fn [txt [real code]] (str/replace txt real code)) idea code-words)

(print "File encoded.  Please enter a name for this idea: ")
(def idea-name (str/trim (read-line)))
(with-open [w (writer (str "idea-" idea-name ".txt"))]
  (.write w safe-idea))

; ex. 23:
(print "55,000 Starmonkey Salute!")

; ex. 24:
(require '[clojure.string :as str)
(import 'java.io.File)

(doseq [file (->> 
               (.listFiles ".")
               (filter #(re-matches #"idea-.+\.txt" (.getName %))))]
  (let [safe-idea (slurp (.getName file))]
    (println
      (reduce 
        (fn [txt [real code]] (str/replace txt code real)) 
        safe-idea
        code-words))))

; ex. 25/26:
(def kitty-toys
  [{:shape "sock", :fabric "cashmere"} {:shape "mouse", :fabric "calico"}
   {:shape "eggroll", :fabric "chenille"}])

(sort-by :fabric kitty-toys)

; ex. 27:
(doseq [toy (sort-by :shape kitty-toys)]
  (println "Blixy has a" (:shape toy) "made of" (:fabric toy)))

; non-printy version that collects the sentences into a seq:
(map #(str "Blixy has a " (:shape %) "made of " (:fabric %)) 
     (sort-by :shape kitty-toys))

; ex. 28:
(def non-eggroll (count (filter #(not= (:shape %) "eggroll") kitty-toys)))

; ex. 29:
(doseq [toy (take-while #(not= (:fabric %) "chenille") kitty-toys)]
  (prn toy))