done adding export-collision functionality, including collision message, in functional core. Next: add imperative shell scaffolding

fcore/common-update.sml

@@ -29,6 +29,18 @@ struct
       (model, [FILE msg])
     end
 
+  fun getCollisionMsg (model: app_type) =
+    let
+      val {squares, canvasWidth, canvasHeight, modalNum, ...} = model
+      val exportString =
+        CollisionTree.toCollisionString (squares, canvasWidth, canvasHeight, modalNum)
+      val msg = EXPORT_COLLISIONS exportString
+
+      val model = AppWith.modalNum (model, 0)
+    in
+      (model, [FILE msg])
+    end
+
   (* unimplemented *)
   fun useSquaresInNormalMode (model, squares) = (model, [])
 

fcore/normal-mode.sml

@@ -363,6 +363,7 @@ struct
     | KEY_CTRL_S => CommonUpdate.getSaveSquaresMsg model
     | KEY_CTRL_L => CommonUpdate.getLoadSquaresMsg model
     | KEY_CTRL_E => CommonUpdate.getExportSquaresMsg model
+    | KEY_CTRL_C => CommonUpdate.getCollisionMsg model
     | USE_SQUARES {squares, canvasWidth, canvasHeight} =>
         useSquares (model, squares, canvasWidth, canvasHeight)
     | SQUARES_LOAD_ERROR => CommonUpdate.squaresLoadError model

fcore/quad-tree.sml

@@ -666,7 +666,6 @@ struct
       val qtree = buildTree (0, 0, size, squares)
       val bintree = merge (qtree, squares)
 
-      val scale = if scale = 0 then 1 else scale
       val f = toCollisionStringFolder scale
       val collisions = BinTree.foldr (f, bintree, [])
       val collisions = String.concatWith ",\n" collisions