assignment done for structures

src/structured_data.clj

@@ -1,16 +1,18 @@
 (ns structured-data)
 
 (defn do-a-thing [x]
-  :-)
+  (let [x2 (+ x x)]
+    (Math/pow x2 x2)))
 
 (defn spiff [v]
-  :-)
+  (+ (get v 0) (get v 2)))
 
 (defn cutify [v]
-  :-)
+  (conj v "<3"))
 
 (defn spiff-destructuring [v]
-  :-)
+  (let [[fst snd thd] v]
+    (+ fst thd)))
 
 (defn point [x y]
   [x y])
@@ -19,96 +21,115 @@
   [bottom-left top-right])
 
 (defn width [rectangle]
-  :-)
+  (let [[[x1 y1] [x2 y2]] rectangle]
+    (- x2 x1)))
 
 (defn height [rectangle]
-  :-)
+  (let [[[x1 y1] [x2 y2]] rectangle]
+    (- y2 y1)))
 
 (defn square? [rectangle]
-  :-)
+  (= (width rectangle) (height rectangle)))
 
 (defn area [rectangle]
-  :-)
+  (* (width rectangle) (height rectangle)))
 
 (defn contains-point? [rectangle point]
-  :-)
+  (let [[[x1 y1] [x2 y2]] rectangle
+        [x y] point]
+    (and (<= x1 x x2) (<= y1 y y2))))
 
 (defn contains-rectangle? [outer inner]
-  :-)
+  (let [[p1 p2] inner]
+    (and (contains-point? outer p1)
+         (contains-point? outer p2))))
 
 (defn title-length [book]
-  :-)
+  (count (:title book)))
 
 (defn author-count [book]
-  :-)
+  (count (:authors book)))
 
 (defn multiple-authors? [book]
-  :-)
+  (> (author-count book) 1))
 
 (defn add-author [book new-author]
-  :-)
+  (assoc book :authors (conj (:authors book) new-author)))
 
 (defn alive? [author]
-  :-)
+  (not (contains? author :death-year)))
 
 (defn element-lengths [collection]
-  :-)
+  (map count collection))
 
 (defn second-elements [collection]
-  :-)
+  (let [sec (fn [x] (first (rest x)))]
+    (map sec collection)))
 
 (defn titles [books]
-  :-)
+  (map :title books))
 
 (defn monotonic? [a-seq]
-  :-)
+  (or (apply <= a-seq)
+      (apply >= a-seq)))
 
 (defn stars [n]
-  :-)
+  (apply str (repeat n \*)))
 
 (defn toggle [a-set elem]
-  :-)
+  (if (contains? a-set elem)
+    (disj a-set elem)
+    (conj a-set elem)))
 
 (defn contains-duplicates? [a-seq]
-  :-)
+  (not (= (count a-seq) (count (set a-seq)))))
 
 (defn old-book->new-book [book]
-  :-)
+  (assoc book :authors (set (:authors book))))
 
 (defn has-author? [book author]
-  :-)
+  (contains? (:authors book) author))
 
 (defn authors [books]
-  :-)
+  (apply clojure.set/union (map :authors books)))
 
 (defn all-author-names [books]
-  :-)
+  (set (map :name (authors books))))
 
 (defn author->string [author]
-  :-)
+  (let [aname (:name author)
+        byear (:birth-year author)
+        dyear (:death-year author)]
+    (if (or byear dyear)
+      (apply str [aname " (" byear " - " dyear ")"])
+      (str aname))))
 
 (defn authors->string [authors]
-  :-)
+  (apply str (interpose ", " (map author->string authors))))
 
 (defn book->string [book]
-  :-)
+  (apply str [(:title book) ", written by " (authors->string (:authors book))]))
 
 (defn books->string [books]
-  :-)
+  (let [nbooks (count books)]
+    (if (= 0 nbooks) "No books."
+      (str nbooks (if (= 1 nbooks) " book. " " books. ")
+           (apply str [(apply str (interpose ". " (map book->string books))) "."])))
+    ))
 
 (defn books-by-author [author books]
-  :-)
+  (filter (fn [book] (has-author? book author)) books))
 
 (defn author-by-name [name authors]
-  :-)
+  (first (filter (fn [author] (= name (:name author))) authors)))
 
 (defn living-authors [authors]
-  :-)
+  (filter (fn [author] (alive? author)) authors))
 
 (defn has-a-living-author? [book]
-  :-)
+  (not (empty? (living-authors (:authors book)))))
 
 (defn books-by-living-authors [books]
-  :-)
+  (filter (fn [book] (has-a-living-author? book)) books))
 
 ; %________%