reimplement parsing code (but program does not compile yet because I have to change type of 'USE_SQUARES' constructure)

fcore/parser/parser.sml

@@ -18,20 +18,32 @@ struct
         end
     | _ => SOME (tokens, grid)
 
+  fun parseLayers (tokens, canvasWidth, canvasHeight, tree, counter) =
+    let
+      val grid = ParseGrid.make (canvasWidth, canvasHeight)
+    in
+      case parseItems (tokens, grid) of
+        SOME (tokens, grid) =>
+          let val tree = LayerTree.insert (counter, grid, tree)
+          in parseLayers (tokens, canvasWidth, canvasHeight, tree, counter + 1)
+          end
+      | NONE => (tokens, tree)
+    end
+
   fun parse string =
     case Lexer.scan string of
       SOME tokens =>
         (case tokens of
-           T.INT canvasWidth :: T.INT canvasHeight :: T.L_BRACE :: tl =>
+           T.INT canvasWidth :: T.INT canvasHeight :: tl =>
              let
-               val grid = ParseGrid.make (canvasWidth, canvasHeight)
+               val maxSide = Int.max (canvasWidth, canvasHeight)
+               val tree = LayerTree.init maxSide
+               val (tokens, tree) = parseLayers
+                 (tl, canvasWidth, canvasHeight, tree, 1)
              in
-               case parseItems (tl, grid) of
-                 SOME (tokens, grid) =>
-                   (case tokens of
-                      [T.R_BRACE] => SOME (canvasWidth, canvasHeight, grid)
-                    | _ => NONE)
-               | NONE => NONE
+               case tokens of
+                 [T.R_BRACE] => SOME tree
+               | _ => NONE
              end
          | _ => NONE)
     | NONE => NONE