from Data.Func import $
import Data.Tuple
import Data.List
-import Data.Functor
import Data.Monoid
import Control.Monad
import Control.Monad.RWST
import Data.Maybe
import Data.Functor
-:: Coord :== (Int, Int)
-:: Position = Inv | Emp | Peg
-:: PegBoard :== {{Position}}
-:: Move :== (Coord, Direction)
-:: Direction = N | E | S | W
+:: Position :== Char
+Inv :== ' '
+Emp :== '.'
+Peg :== 'o'
+
+:: Direction :== Int
+N :== 0
+E :== 1
+S :== 2
+W :== 3
+
+:: Coord = {x::Int, y::Int}
+:: Move = {c::Coord, d::Direction}
+:: PegBoard :== {{#Position}}
+
:: Solver a :== RWST () [PegBoard] PegBoard Maybe a
european :: PegBoard
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'
-
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)
+transform c=:{x,y} d = case d of
+ N = {c&y=y+1}; S = {c&y=y-1}; W = {c&x=x+1}; E = {c&x=x-1}
getPos :: Coord -> Solver Position
-getPos (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
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
+move {c=c=:{x=tx,y=ty}, d}
+# sc=:{x=sx,y=sy} = transform c d
+# fc=:{x=fx,y=fy} = transform sc d
+= get >>= \b->liftM3 tuple3 (getPos fc) (getPos sc) (getPos c) >>= \f->case f of
(Peg, Peg, Emp)
# b = {{{c\\c<-:r}\\r<-:b} & [fy,fx]=Emp, [sy,sx]=Emp, [ty,tx]=Peg}
= tell [b] >>| put b
_ = empty
-getCoords :: (Position -> Bool) PegBoard -> [Coord]
-getCoords f b = [(x, y)\\r<-:b & y<-[0..] , c<-:r & x<-[0..] | f c]
+getCoords :: (Char -> Bool) PegBoard -> [Coord]
+getCoords f b = [{x=x,y=y}\\r<-:b & y<-[0..] , c<-:r & x<-[0..] | f c]
win :: (PegBoard -> Bool)
-win = (==) 1 o length o getCoords (\c->c=:Peg)
+win = (==) 1 o length o getCoords ((==)Peg)
printPegBoard :: PegBoard -> String
-printPegBoard b = 'Text'.join "\n" [{#toChar x\\x<-:r}\\r <-: b]
+printPegBoard b = 'Text'.join "\n" [r\\r <-: b]
moves :: Solver [Move]
-moves = gets $ \b->[(c,d)\\c<-getCoords (\c->c=:Emp) b, d<-[N,E,S,W]]
+moves = gets $ \b->[{c=c,d=d}\\c<-getCoords ((==)Emp) b, d<-[N,E,S,W]]
solve :: PegBoard -> Maybe [PegBoard]
solve b = snd <$> evalRWST (tell [b] >>| solver) () b