fix bugs related to parsing and loading file (did not implement new BNF grammar properly)

fcore/quad-tree.sml

@@ -460,7 +460,7 @@ struct
   fun toSaveStringFolder ({x, ex, y, ey, data = {r, g, b, a}}, acc) =
     let
       val item = String.concat
-        [ "["
+        [ " { "
         , Int.toString x
         , " "
         , Int.toString y
@@ -476,7 +476,7 @@ struct
         , Int.toString b
         , " "
         , Int.toString a
-        , " ] "
+        , " } "
         ]
     in
       item :: acc
@@ -486,9 +486,11 @@ struct
     let
       val qtree = buildTree (0, 0, size, grid)
       val bintree = merge (qtree, grid)
-      val str = BinTree.foldr (toSaveStringFolder, bintree, [])
+      val coords = BinTree.foldr (toSaveStringFolder, bintree, [])
+      val coords = String.concat coords
+      val str = " [ " ^ coords ^ " ] "
     in
-      String.concat str :: acc
+      str :: acc
     end
 
   fun toSaveString (layerTree, canvasWidth, canvasHeight) =
@@ -496,7 +498,7 @@ struct
       val size = Int.max (canvasWidth, canvasHeight)
       val f = toSaveStringTreeFolder size
 
-      val initial = ["}"]
+      val initial = ["}\n"]
       val acc = LayerTree.foldr (f, layerTree, initial)
       val acc =
         String.concat