fix compile errors left in previous commit

fcore/parser/parser.sml

@@ -35,7 +35,7 @@ struct
       SOME (tokens, grid) => loopParseItems (tokens, grid)
     | NONE => NONE
 
-  fun parseLayers (tokens, canvasWidth, canvasHeight, tree, counter) =
+  fun parseLayer (tokens, canvasWidth, canvasHeight, tree, counter) =
     case tokens of
       T.L_BRACKET :: tl =>
         let
@@ -44,12 +44,23 @@ struct
           case startParseItems (tl, grid) of
             SOME (T.R_BRACKET :: tl, grid) =>
               let val tree = LayerTree.insert (counter, grid, tree)
-              in parseLayers (tl, canvasWidth, canvasHeight, tree, counter + 1)
+              in SOME (tl, tree)
               end
           | SOME _ => NONE
-          | NONE => (tokens, tree)
+          | NONE => NONE
         end
-    | _ => (tokens, tree)
+    | _ => NONE
+
+  fun parseLayerLoop (tokens, canvasWidth, canvasHeight, tree, counter) =
+    case parseLayer (tokens, canvasWidth, canvasHeight, tree, counter) of
+      SOME (tl, tree) =>
+        parseLayerLoop (tl, canvasWidth, canvasHeight, tree, counter + 1)
+    | NONE => SOME (tokens, tree)
+
+  fun startParseLayer (tokens, canvasWidth, canvasHeight, tree) =
+    case parseLayer (tokens, canvasWidth, canvasHeight, tree, 1) of
+      SOME (tl, tree) => parseLayerLoop (tl, canvasWidth, canvasHeight, tree, 2)
+    | NONE => NONE
 
   fun parse string =
     case Lexer.scan string of
@@ -59,12 +70,12 @@ struct
              let
                val maxSide = Int.max (canvasWidth, canvasHeight)
                val tree = LayerTree.init maxSide
-               val (tokens, tree) = parseLayers
-                 (tl, canvasWidth, canvasHeight, tree, 1)
              in
-               case tokens of
-                 [T.R_BRACE] => SOME (canvasWidth, canvasHeight, tree)
-               | _ => NONE
+               case startParseLayer (tl, canvasWidth, canvasHeight, tree) of
+                 SOME ([T.R_BRACE], tree) =>
+                   SOME (canvasWidth, canvasHeight, tree)
+               | SOME _ => NONE
+               | NONE => NONE
              end
          | _ => NONE)
     | NONE => NONE