add helper module to work with mapped areas

src/mapped_area.clj

@@ -0,0 +1,73 @@
+(ns mapped-area
+  (:require [clojure.string :as string]))
+
+(def test-map
+"abcd
+efgh
+ijkl")
+
+(defn read-mapped-area
+  {:test
+   #(do
+      (let [a (read-mapped-area test-map)]
+        (assert (= \i (get-in a [0 0])))
+        (assert (= \f (get-in a [1 1])))
+        (assert (= \a (get-in a [0 2])))
+        (assert (nil? (get-in a [10 10])))
+        (assert (nil? (get-in a [1 3])))
+        (assert (= \h (get-in a [3 1])))))}
+  [s]
+  (let [ss (string/split-lines s)
+        lines (count ss)]
+    (->>
+     (reverse ss)
+     (apply interleave)
+     (partition lines)
+     (mapv vec))))
+
+(defn print-mapped-area [a]
+  (let [lines (count (first a))]
+    (doall
+     (->>
+      (map reverse a)
+      (apply interleave)
+      (partition lines)
+      (map (partial apply str))
+      (map println))))
+  a)
+
+(comment
+  (print-mapped-area (read-mapped-area test-map))
+  )
+
+(defn- h
+  {:test #(do (assert (= (h (read-mapped-area test-map)) 3)))}
+  [a]
+  (count (first a)))
+
+(defn- w
+  {:test #(do (assert (= (w (read-mapped-area test-map)) 4)))}
+  [a]
+  (count a))
+
+(defn mapped?
+  {:test
+   #(do
+      (let [a (read-mapped-area test-map)]
+        (assert (true? (mapped? a 1 1)))
+        (assert (true? (mapped? a [2 2])))
+        (assert (false? (mapped? nil -1 0)))
+        (assert (false? (mapped? a 4 0)))
+        (assert (true? (mapped? a 3 1)))
+        (assert (false? (mapped? a 1 3)))))}
+  ([a [x y]] (mapped? a x y))
+  ([a x y]
+   (and (>= x 0)
+        (>= y 0)
+        (< x (w a))
+        (< y (h a)))))
+
+(test #'read-mapped-area)
+(test #'h)
+(test #'w)
+(test #'mapped?)