minor changes

cw/src/Challenges.hs

@@ -171,7 +171,7 @@ addStrsToGrid rg gen (s:ss) = addStrsToGrid newGrid newGen ss
  --| returns a list of valid orientations for the     |--
  --| string at that position                          |--}
 validDirs :: RandGrid -> String -> Posn -> [Orientation]
-validDirs rg s (x,y) = map fst $ filter (\b -> snd b == True) (zipF ( checkDir rg s (x,y) ) dirs)
+validDirs rg s (x,y) = map fst $ filter ((True==) . snd) (zipF ( checkDir rg s (x,y) ) dirs)
     where dirs = [Forward,Back,Up,Down,UpForward,UpBack,DownForward,DownBack]
 
 
@@ -330,15 +330,13 @@ closedParse :: Parser LamExpr -> Parser LamExpr
 closedParse p = do e <- p
                    if free e then empty else return e
 
-{--| finds if an expression contains free variables   |--
- --|                                                  |--}
+{--| finds if an expression contains free variables   |--}
 free :: LamExpr -> Bool
 free (LamVar _)     = True
 free (LamAbs x  e ) = freeVar x e
 free (LamApp e1 e2) = free e1 && free e2
 
-{--| finds if a given variable is free in an expr     |--
- --|                                                  |--}
+{--| finds if a given variable is free in an expr     |--}
 freeVar :: Int -> LamExpr -> Bool
 freeVar x (LamVar y)                 = not $ x == y
 freeVar x (LamAbs y e)   | x == y    = False