Word search combinations generator

wordsearch.hs

import Data.List ((\\))

data Cell = Middle
          | North
          | NorthEast
          | East
          | SouthEast
          | South
          | SouthWest
          | West
          | NorthWest
	deriving Eq
		  
cells = [North, NorthEast, East, SouthEast, South, SouthWest, West, NorthWest, Middle]

neighbours cell = case cell of
    Middle    -> [North, NorthEast, East, SouthEast, South, SouthWest, West, NorthWest]
    North     -> [NorthEast, East, Middle, West, NorthWest]
    NorthEast -> [East, Middle, North]
    East      -> [SouthEast, South, Middle, North, NorthEast]
    SouthEast -> [South, Middle, East]
    South     -> [SouthWest, West, Middle, East, SouthEast]
    SouthWest -> [West, Middle, South]
    West      -> [NorthWest, North, Middle, South, SouthWest]
    NorthWest -> [North, Middle, West]

labeler table cell = case cell of
    Middle    -> table!!1!!1
    North     -> table!!0!!1
    NorthEast -> table!!0!!2
    East      -> table!!1!!2
    SouthEast -> table!!2!!2
    South     -> table!!2!!1
    SouthWest -> table!!2!!0
    West      -> table!!1!!0
    NorthWest -> table!!0!!0
	
pathsFrom start used = [start:rest | rest <- rests]
    where unused = (neighbours start) \\ used
          used' = start:used
          rests = []:(unused >>= flip pathsFrom used')
	
allPaths = cells >>= (flip pathsFrom [])

validPaths = filter ((>= 3) . length) allPaths

validWords table = [map (labeler table) path | path <- validPaths]

mytable =
    [
    [ 'E', 'V', 'É' ],
    [ 'Ő', 'R', 'I' ],
    [ 'F', 'D', 'K' ]
    ]

-- example: validWords mytable