Cleanup

[cleanpeg.git] / peg.icl

diff --git a/peg.icl b/peg.icl
index ed1a964..0e784c2 100644 (file)
--- a/peg.icl
+++ b/peg.icl
@@ -6,6 +6,8 @@ from Text import class Text, instance Text String
 import qualified Text
 from Data.Func import $
 import Data.Tuple
+import Data.List
+import Data.Functor
 import Data.Monoid
 import Control.Monad
 import Control.Monad.RWST
@@ -31,30 +33,22 @@ european =
        ,{Inv, Inv, Peg, Peg, Peg, Inv, Inv}
        }
 
-empty = RWST $ \_ _->Nothing
-(<|>) (RWST fa) (RWST fb) = RWST $ \r s->case fa r s of
-       Nothing = fb r s
-       x = x
+empty = RWST \_ _->Nothing
+(<|>) (RWST fa) (RWST fb) = RWST \r s->maybe (fb r s) Just (fa r s)
 
 instance toChar Position where
        toChar p = case p of Inv = ' '; Emp = '.'; Peg = 'o'
 
-instance == Position where
-       (==) Inv Inv = True
-       (==) Emp Emp = True
-       (==) Peg Peg = True
-       (==) _ _ = False
-
 transform :: Coord Direction -> Coord
 transform (x, y) d = case d of N = (x, y+1); S = (x, y-1); W = (x+1, y); E = (x-1, y)
 
 getPos :: Coord -> Solver Position
-getPos c=:(x, y) = get >>= \b->if (valid b) empty (pure b.[y].[x])
+getPos (x, y) = get >>= \b->if (valid b) empty (pure b.[y].[x])
 where 
-       valid b = y<0 || x<0 || y >= size b || x >= size b.[0] || b.[y].[x] == Inv
+       valid b = y<0 || x<0 || y >= size b || x >= size b.[0] || b.[y].[x] =: Inv
 
-applyMove :: Move -> Solver ()
-applyMove (tc=:(tx, ty), d)
+move :: Move -> Solver ()
+move (tc=:(tx, ty), d)
 # sc=:(sx, sy) = transform tc d
 # fc=:(fx, fy) = transform sc d
 = get >>= \b->liftM3 tuple3 (getPos fc) (getPos sc) (getPos tc) >>= \f->case f of
@@ -67,20 +61,19 @@ getCoords :: (Position -> Bool) PegBoard -> [Coord]
 getCoords f b = [(x, y)\\r<-:b & y<-[0..] , c<-:r & x<-[0..] | f c]
 
 win :: (PegBoard -> Bool)
-win = (==) 1 o length o getCoords ((==)Peg)
+win = (==) 1 o length o getCoords (\c->c=:Peg)
 
 printPegBoard :: PegBoard -> String
-printPegBoard b = 'Text'.join "\n" ["\n":[{#toChar x\\x<-:r}\\r <-: b]]
+printPegBoard b = 'Text'.join "\n" [{#toChar x\\x<-:r}\\r <-: b]
 
-getMoves :: Solver [Move]
-getMoves = gets (\b->[(c,d)\\c<-getCoords ((==)Emp) b, d<-[N,E,S,W]])
+moves :: Solver [Move]
+moves = gets $ \b->[(c,d)\\c<-getCoords (\c->c=:Emp) b, d<-[N,E,S,W]]
 
 solve :: PegBoard -> Maybe [PegBoard]
 solve b = snd <$> evalRWST (tell [b] >>| solver) () b
 where
-       solver = get >>= \board->case win board of
-               True = get >>= \b->tell [b]
-               False = getMoves
-                       >>= foldr (<|>) empty o map (\m->applyMove m >>| solver)
+       solver = get >>= \board->if (win board)
+               (get >>= tell o pure)
+               (moves >>= foldr (<|>) empty o map (\m->move m >>| solver))
 
 Start = 'Text'.join "\n" o map printPegBoard <$> solve european