— CPSC 312 – 2021 – Games in Haskell
—– Same as Magic_sum except that it hashes
module MagicSum_hash where
import Hash
— To run it, try:
— ghci
— :load MagicSum_ord_hash
data State = State InternalState [Action] — internal_state available_actions
deriving (Ord, Eq, Show)
data Result = EndOfGame Double State — end of game: value, starting state
| ContinueGame State — continue with new state
deriving (Eq, Show)
type Game = Action -> State -> Result
type Player = State -> Action
—— The Magic Sum Game ——-
data Action = Action Int — a move for a player is just an Int
deriving (Ord,Eq)
type InternalState = ([Action],[Action]) — (self,other)
instance Hash State where
hash (State (a1,a2) a3) = hash (a1++a2++a3)
instance Hash Action where
hash (Action a) = hash a
instance Show Action where
show (Action i) = show i
instance Read Action where
readsPrec i st = [(Action a,rst) | (a,rst) <- readsPrec i st]
-- insert into a sorted list
insert :: Ord a => a -> [a] -> [a]
insert e [] = [e]
insert e (h:t)
| e <= h = (e:h:t)
| otherwise = h: (insert e t)
magicsum :: Game
magicsum move (State (mine,others) available)
| win move mine = EndOfGame 1 magicsum_start -- agent wins
| available == [move] = EndOfGame 0 magicsum_start -- no more moves, draw
| otherwise =
ContinueGame (State (others,move:mine) -- only difference with MagicSum.hs
[act | act <- available, act /= move])
magicsum_start = State ([],[]) [Action n | n <- [1..9]]
-- win n ns = the agent wins if it selects n given it has already selected ns
win :: Action -> [Action] -> Bool
win (Action n) ns = or [n+x+y==15 | Action x <- ns, Action y <- ns, x/=y]
------- A Player -------
simple_player :: Player
-- this player has an ordering of the moves, and chooses the first one available
simple_player (State _ avail) = head [Action e | e <- [5,6,4,2,8,1,3,7,9],
Action e `elem` avail]
-- Test cases
-- magicsum magicsum_start (simple_player magicsum_start)
-- a i = Action i -- make it easier to type
-- as lst = [Action i | i <- lst]
-- magicsum (a 6) (State (as [3,5], as [2,7]) (as [1,4,6,8,9]))
-- magicsum (a 3) (State (as [5,7], as [2,9]) (as [1,3,4,6,8]))
-- Why is it called the "magic sum game"?
-- The following is a magic square:
-- 294
-- 753
-- 618