minor optimisation (do not have to branch on NO_TRIANGLE | FIRST | SECOND twice in update function; update function was branching on this itself, and call to 'getTriangleStageVector' was branching again which was redundant)

functional-core/app-update.sml

@@ -93,10 +93,7 @@ struct
         (0, Real32.fromInt mouseX, Real32.fromInt mouseY, r, g, b)
   end
 
-  fun getTriangleStageVector (model: app_type, drawVec) =
-    case #triangleStage model of
-      NO_TRIANGLE => drawVec
-    | FIRST {x1, y1} =>
+  fun getFirstTriangleStageVector (x1, y1, drawVec) =
     let
       val halfWidth = Real32.fromInt (Constants.windowWidth div 2)
       val halfHeight = Real32.fromInt (Constants.windowHeight div 2)
@@ -113,7 +110,8 @@ struct
     in
       Vector.concat [firstVec, drawVec]
     end
-    | SECOND {x1, y1, x2, y2} =>
+
+  fun getSecondTriangleStageVector (x1, y1, x2, y2, drawVec) =
     let
       val halfWidth = Real32.fromInt (Constants.windowWidth div 2)
       val halfHeight = Real32.fromInt (Constants.windowHeight div 2)
@@ -141,6 +139,14 @@ struct
       Vector.concat [firstVec, secVec, drawVec]
     end
 
+  fun getTriangleStageVector (model: app_type, drawVec) =
+    case #triangleStage model of
+      NO_TRIANGLE => drawVec
+    | FIRST {x1, y1} =>
+        getFirstTriangleStageVector (x1, y1, drawVec)
+    | SECOND {x1, y1, x2, y2} =>
+        getSecondTriangleStageVector (x1, y1, x2, y2, drawVec)
+
   fun update (model, mouseX, mouseY, inputMsg) =
     let
       open DrawMessage
@@ -183,7 +189,7 @@ struct
                    end
                | FIRST {x1, y1} =>
                    let
-                     val drawVec = getTriangleStageVector (model, buttonVec)
+                     val drawVec = getFirstTriangleStageVector (x1, y1, buttonVec)
                      val drawMsg = DRAW_BUTTON drawVec
 
                      val newTriangleStage = SECOND
@@ -195,7 +201,8 @@ struct
                    end
                | SECOND {x1, y1, x2, y2} =>
                    let
-                     val drawVec = getTriangleStageVector (model, buttonVec)
+                     val drawVec = 
+                       getSecondTriangleStageVector (x1, y1, x2, y2, buttonVec)
                      val drawMsg = DRAW_BUTTON drawVec
 
                      val newTriangleStage = NO_TRIANGLE