scaffolding in preparation for implementing undo

functional-core/app-init.sml

@@ -23,6 +23,7 @@ struct
       , xClickPoints = xClickPoints
       , yClickPoints = yClickPoints
       , graphLines = graphLines
+      , undo = []
       }
     end
 

functional-core/app-type.sml

@@ -23,6 +23,7 @@ sig
     , xClickPoints: Real32.real vector
     , yClickPoints: Real32.real vector
     , graphLines: Real32.real vector
+    , undo: (int * int) list
     }
 end
 
@@ -59,5 +60,6 @@ struct
     , xClickPoints: Real32.real vector
     , yClickPoints: Real32.real vector
     , graphLines: Real32.real vector
+    , undo: (int * int) list
     }
 end

functional-core/app-update.sml

@@ -103,4 +103,10 @@ struct
     | MOUSE_LEFT_CLICK => mouseLeftClick (model, mouseX, mouseY)
     | RESIZE_WINDOW {width, height} =>
         resizeWindow (model, mouseX, mouseY, width, height)
+    | UNDO_ACTION =>
+        let
+          val _ = print "undo action\n"
+        in
+          (model, NO_DRAW, mouseX, mouseY)
+        end
 end

functional-core/app-with.sml

@@ -28,6 +28,7 @@ struct
         , windowWidth
         , windowHeight
         , graphLines
+        , undo
         } = app
     in
       { triangleStage = newTriangleStage
@@ -37,6 +38,7 @@ struct
       , windowWidth = windowWidth
       , windowHeight = windowHeight
       , graphLines = graphLines
+      , undo = undo
       }
     end
 
@@ -50,6 +52,7 @@ struct
         , windowWidth
         , windowHeight
         , graphLines
+        , undo
         } = app
 
       val newTriangle = {x1 = x1, y1 = y1, x2 = x2, y2 = y2, x3 = x3, y3 = y3}
@@ -62,6 +65,7 @@ struct
       , windowWidth = windowWidth
       , windowHeight = windowHeight
       , graphLines = graphLines
+      , undo = undo
       }
     end
 
@@ -77,6 +81,7 @@ struct
         , graphLines = _
         , triangles
         , triangleStage
+        , undo
         } = app
       val xClickPoints = ClickPoints.generate (wStart, wFinish)
       val yClickPoints = ClickPoints.generate (hStart, hFinish)
@@ -91,6 +96,7 @@ struct
       , triangleStage = triangleStage
       , windowWidth = windowWidth
       , windowHeight = windowHeight
+      , undo = undo
       }
     end