Migrate sample bots; add (bad) biggest-space bot; add more board fns

src/crosscram/game.clj

@@ -92,13 +92,32 @@ perspective. Player ID will be used modulo 2."
     domino
     (vec (map (comp vec reverse) domino))))
 
+(defn posint?
+  "Return logical true if given a positive integer."
+  [x]
+  (and (integer? x) (pos? x)))
+
 ;;;; Boards
 
 (defn mk-board
-  "Given a dimensions vector of [rows, columns], generate an empty board."
+  "Given a dimensions vector of [rows, columns], generate an empty board.
+Both dimensions must be positive integers."
   [[rows columns]]
+  {:pre [(posint? rows) (posint? columns)]}
   (vec (repeat rows (vec (repeat columns nil))))) ;; TODO dimension-agnostic
 
+(defn board-size
+  "Get the board size as a vector of row, column."
+  [board]
+  [(count board) (count (first board))])
+
+(defn on-board?
+  "Test if a row/column coordinate pair is a board coordinate."
+  [board [rv cv]]
+  (let [[rows cols] (board-size board)]
+    (and (<= 0 rv (dec rows))
+         (<= 0 cv (dec cols)))))
+
 (defn rotate-board
   "Rotate a board from player 0's perspective to the specified player's
 perspective. Player ID will be used modulo 2."

src/crosscram/samples/biggest_space.clj

@@ -0,0 +1,48 @@
+(ns crosscram.samples.biggest-space
+  "Pick a space that has the widest open area around it. Doesn't do
+particularly well against random.clj. Feel free to hack on this bot.
+Some of these utility functions might be useful."
+  (:require [crosscram.game :as cc]))
+
+(defn canonical
+  "Order a horizontal piece in left to right square order."
+  [piece]
+  (let [[[row c0] [_ c1]] piece
+        left (min c0 c1)]
+    [[row left] [row (inc left)]]))
+
+(defn neighborhood
+  "Get board values for a neighborhood centered on a possible move with
+`radius` squares in each direction. Returns a vector of row vectors
+containing the values from the board."
+  [board radius move]
+  (let [[[row left] _] (canonical move)]
+    (vec (for [y (range (- row radius) (+ row radius 1))]
+           (vec (for [x (range (- left radius) (+ left radius 2))]
+                  (cc/lookup-square board [y x])))))))
+
+(defn count-nil
+  "Given a neighborhood, count the nils."
+  [hood]
+  (count (filter nil? (apply concat hood))))
+
+(defn pick
+  "Pick a random move from the highest-score cohort."
+  [candidates]
+  (->> candidates
+       (sort-by :score >)
+       (partition-by :score)
+       (drop-while empty?)
+       first
+       rand-nth
+       :move))
+
+(def radius 3)
+
+(defn make-move
+  [game]
+  (let [board (:board game)
+        candidates (for [m (cc/available-moves board)]
+                     {:move m
+                      :score (count-nil (neighborhood board radius m))})]
+    (pick candidates)))

src/crosscram/samples/eager_walk.clj

@@ -1,6 +1,6 @@
 (ns crosscram.samples.eager-walk
   "Pick the first available space."
-  (:require [crosscram.board :as board]))
+  (:require [crosscram.game :as cc]))
 
 (defn make-move [game]
-  (first (board/available-moves game)))
+  (first (cc/available-moves (:board game))))

src/crosscram/samples/random.clj

@@ -1,6 +1,6 @@
 (ns crosscram.samples.random
   "Pick a random available space."
-  (:require [crosscram.board :as board]))
+  (:require [crosscram.game :as cc]))
 
 (defn make-move [game]
-  (rand-nth (board/available-moves game)))
+  (rand-nth (cc/available-moves (:board game))))

test/crosscram/test/game.clj

@@ -39,6 +39,14 @@
     (is (= (place-domino empty [[0 0] [0 1]] 5)
            [[5 5 nil] [nil nil nil]]))
     ;; api
+    (is (= (board-size empty) [2 3]))
+    (are [pos on?] (= (boolean (on-board? empty pos)) on?)
+         [0 0] true
+         [-1 0] false
+         [0 -2] false
+         [2 3] false
+         [1 2] true
+         [2 2] false)
     (is (= (lookup-square empty [0 2]) nil))
     (is (= (lookup-square move0 [0 2]) 0))
     (is (= (lookup-square move0 [1 2]) 0))