Check procs for sub boards.

src/libmttt.nim

@@ -1,21 +1,10 @@
-import strformat
+import sets
 
-type
-  Board*[T] =
-    array[3, array[3, T]]
-
-  Mark* = enum
-    mPlayer1, # The mark of the fist player
-    mPlayer2, # The mark of the second player
-    mFree     # This mark signals that a cell is empty
-
-  BoardResult* = enum
-    rPlayer1, # The first player has won the board
-    rPlayer2, # The second player has won the board
-    rDraw,    # There is no winner. The board has ended in a draw
-    rOpen     # The game on this board is still ongoing
+include libmttt/types
+include libmttt/checks
 
 proc newBoard[T](initial: T): Board[T] =
+  ## Create a new game board filled with the initial value
   result = [
     [initial, initial, initial],
     [initial, initial, initial],
@@ -23,20 +12,38 @@ proc newBoard[T](initial: T): Board[T] =
   ]
 
 proc newMetaBoard[T](val: T): Board[Board[T]] =
+  ## Create the meta board, composed out of 9 normal boards.
   [
     [newBoard(val), newBoard(val), newBoard(val)],
     [newBoard(val), newBoard(val), newBoard(val)],
     [newBoard(val), newBoard(val), newBoard(val)]
   ]
 
-proc createBoard*(): Board[Board[Mark]] =
-  newMetaBoard(mFree)
+proc newGame*(player1, player2: Player): GameState =
+  ## Create a new game board
+  GameState(
+    players: [player1, player2],
+    currentPlayer: player1,
+    result: rOpen,
+    board: newMetaBoard(mFree))
 
 proc checkBoard*(board: Board[Mark]): BoardResult =
-  for x in 0 ..< board.len:
-    for y in 0 ..< board.len:
-      echo fmt"Cell (x: {x}, y: {y}) = {board[x][y]}"
+  ## Perform a check on a single sub board to see its result
+
+  # Create a seconded, transposed board.
+  # This way 'checkRows' can be used to check the columns 
+  var transposed = newBoard(mFree);
+  for x in 0 .. 2:
+      for y in 0 .. 2:
+        transposed[x][y] = board[y][x]
+
+  var states: HashSet[BoardResult]
+  states.init()    
+  for b in [board, transposed]:
+    states.incl(checkRows(b))
+  return selectResult(states)
+    
 
 proc checkBoard*(board: Board[Board[Mark]]): BoardResult =
+  ## Perform a check on a metaboard to see the overall game result
   rOpen
-

src/libmttt/checks.nim

@@ -0,0 +1,42 @@
+import sets
+
+import types
+
+proc selectResult(states: HashSet[BoardResult]): BoardResult =
+  ## Analyse a set of results and select the correct one
+  if states.contains(rPlayer1) and
+      states.contains(rPlayer2):
+      raise newException(Exception, "Both players cannot win at the same time")
+
+  if states.contains(rPlayer1):
+    return rPlayer1
+  if states.contains(rPlayer2):
+    return rPlayer2
+  if states.contains(rOpen):
+    return rOpen
+  return rDraw
+
+proc checkRow(row: array[3, Mark]): BoardResult =
+  var tokens = toHashSet(row)
+  # A player has won
+  if tokens.len == 1 and not tokens.contains(mFree):
+    let rowResult = tokens.pop()
+    if rowResult == mPlayer1:
+      return rPlayer1
+    else:
+      return rPlayer2
+  # The row is full
+  if tokens.len == 2 and not tokens.contains(mFree):
+    return rDraw
+  # There are still cells free in this row
+  else:
+    return rOpen
+
+proc checkRows(board: Board[Mark]): BoardResult =
+  ## Iterate over all rows of this board and return the result.
+  var states: HashSet[BoardResult]
+  states.init()
+  for row in board:
+    states.incl(checkRow(row))
+  return states.selectResult()
+  

src/libmttt/types.nim

@@ -0,0 +1,39 @@
+import strformat
+type
+  ## A game board is a simple 2 dimensional array.
+  ## Markers of any type can be placed inside the cells
+  Board*[T] = array[3, array[3, T]]
+
+  Player* = ref object
+    mark*: Mark
+    name*: string
+
+  Mark* = enum
+    mPlayer1, ## The mark of the fist player
+    mPlayer2, ## The mark of the second player
+    mFree     ## This mark signals that a cell is empty
+
+  BoardResult* = enum
+    rPlayer1, ## The first player has won the board
+    rPlayer2, ## The second player has won the board
+    rDraw,    ## There is no winner. The board has ended in a draw
+    rOpen     ## The game on this board is still ongoing
+
+  GameState* = ref object
+    ## Contains all state for a pint in the game
+    board*: Board[Board[Mark]]
+    players*: array[2, Player]
+    currentPlayer*: Player
+    result*: BoardResult
+    turn*: int
+
+proc `$`*(player: Player): string = 
+  $player.name
+
+proc `$`*(game: GameState): string = 
+  &"""
+  Game is in turn {$game.turn}
+  Players are: '{$game.players[0]}' and '{$game.players[1]}'
+  Current player: '{$game.currentPlayer}'
+  Game state is: {$game.result}
+  """

tests/test1.nim

@@ -9,7 +9,41 @@ import unittest
 
 import libmttt
 
-test "debugging":
-  var metaBoard = createBoard()
-  metaBoard[0][0][1][1] = mPlayer1
-  echo metaBoard[0][0].checkBoard()
+suite "Test the board result checker":
+  setup:
+    var
+      player1 = Player(name: "Max")
+      player2 = Player(name: "Adam")
+      state: GameState = newGame(player1, player2)
+
+  test "row checking":    
+    state.board[0][0] = [
+      [mFree, mFree, mFree],
+      [mPlayer1, mPlayer1, mPlayer1],
+      [mFree, mFree, mFree]
+    ]
+    check checkBoard(state.board[0][0]) == rPlayer1
+
+  test "column checking":      
+    state.board[0][0] = [
+      [mPlayer2, mFree, mPlayer1],
+      [mPlayer2, mPlayer1, mFree],
+      [mPlayer2, mPlayer1, mFree]
+    ]
+    check checkBoard(state.board[0][0]) == rPlayer2
+
+  test "check for draw":      
+    state.board[0][0] = [
+      [mPlayer1, mPlayer2, mPlayer1],
+      [mPlayer2, mPlayer1, mPlayer1],
+      [mPlayer2, mPlayer1, mPlayer2]
+    ]
+    check checkBoard(state.board[0][0]) == rDraw
+
+  test "check for open board":      
+    state.board[0][0] = [
+      [mPlayer1, mPlayer2, mFree],
+      [mPlayer1, mFree, mPlayer1],
+      [mFree, mPlayer1, mPlayer2]
+    ]
+    check checkBoard(state.board[0][0]) == rOpen