Solve the exercises

.travis.yml

@@ -1,6 +1,6 @@
 language: clojure
-lein: lein2
-script: lein2 midje :config .midje-grading-config.clj
+lein: lein
+script: lein midje :config .midje-grading-config.clj
 jdk:
   - openjdk7
 notifications:

src/predicates.clj

@@ -1,41 +1,50 @@
 (ns predicates)
 
 (defn sum-f [f g x]
-  :-)
+  (+ (f x) (g x)))
 
 (defn less-than [n]
-  :-)
+  (fn [k] (< k n)))
+
+(defn greater-than [n]
+  (fn [k] (> k n)))
 
 (defn equal-to [n]
-  :-)
+  (fn [k] (= 0 (compare k n))))
+
+(defn key->predicate [a-key]
+  (fn [a-map] (contains? a-map a-key)))
 
 (defn set->predicate [a-set]
-  :-)
+  (fn [x] (contains? a-set x)))
 
 (defn pred-and [pred1 pred2]
-  :-)
+  (fn [x] (and (pred1 x) (pred2 x))))
 
 (defn pred-or [pred1 pred2]
-  :-)
+  (fn [x] (true? (or (pred1 x) (pred2 x)))))
 
 (defn whitespace? [character]
   (Character/isWhitespace character))
 
 (defn blank? [string]
-  :-)
+  (or  (every? whitespace? string) 
+       (empty? string) 
+       (nil? string)))
 
 (defn has-award? [book award]
-  :-)
+  (contains? (book :awards) award))
 
 (defn HAS-ALL-THE-AWARDS? [book awards]
-  :-)
+  (every? #(has-award? book %) awards))
 
 (defn my-some [pred a-seq]
-  :-)
+  (first (filter #(not (false? %)) (map pred a-seq))))
 
 (defn my-every? [pred a-seq]
-  :-)
+  (= (count a-seq) (count (filter #(not (false? %)) (map pred a-seq)))))
 
 (defn prime? [n]
-  :-)
+  (let [divisible-by? (fn [k] (= 0 (mod n k)))]
+    (not (some divisible-by? (range 2 n)))))
 ;^^