1 files changed, 45 insertions, 0 deletions
diff --git a/src/Mahjong/Tile.hs b/src/Mahjong/Tile.hs
new file mode 100644
index 0000000..05e2f89
--- /dev/null
+++ b/src/Mahjong/Tile.hs
@@ -0,0 +1,45 @@
+module Tile where
+
+import Data.Char (toUpper)
+import Data.List (sort)
+import Data.Maybe
+import Control.Monad
+
+data MCol = Man | Pin | Sou | Cha
+    deriving (Eq,Ord)
+data MTile = MTile MCol Int
+    deriving (Eq,Ord)
+
+charMcol = [(Man,'M'),(Pin,'P'),(Sou,'S'),(Cha,'C')]
+instance Show MCol where
+    show x = [snd a | a <-charMcol, fst a == x]
+
+instance Read MCol where
+    readsPrec p r = [(fst a,t)|(c,t) <- lex r, a <- charMcol, map toUpper c == [snd a]]
+
+instance Show MTile where
+    show (MTile a b) = show b ++ show a
+
+instance Read MTile where
+    readsPrec p r = [ (MTile col n,u) | (c1,t)<- lex r, 
+                                        let n = (read c1)::Int, 
+                                        (c2,u) <-lex t, 
+                                        let col=(read c2)::MCol]
+
+isCha c@(MTile col n) = (col == Cha)
+isLaoTou c@(MTile col n) = ((n == 1) || (n == 9)) && (not $ isCha c)
+is19 c@(MTile col n) = (isCha c) || (isLaoTou c)
+
+orderedTile = sort $ [MTile c n | c<-[Man,Pin,Sou], n <-[1..9]] ++ (map (MTile Cha) [1..7])
+
+nextTile p = if xs /= [] then Just $ head xs
+            else Nothing
+    where (x:xs) = dropWhile (/= p) orderedTile
+
+nextTile' :: Maybe MTile -> Maybe MTile
+nextTile' jp = do
+    p <- jp
+    nx@(MTile c n) <- nextTile p
+    guard ((c /= Cha) && (n /= 9))
+    return nx
+