slight refactoring (move pure parsing functions to functional core in a separate file)

functional-core/app/app-init.sml

@@ -0,0 +1,52 @@
+signature APP_INIT =
+sig
+  val fromWindowWidthAndHeight: int * int -> AppType.app_type
+end
+
+structure AppInit :> APP_INIT =
+struct
+  open AppType
+
+  fun helpFromWidthAndHeight
+    (windowWidth, windowHeight, wStart, wFinish, hStart, hFinish) : app_type =
+    let
+      val xClickPoints = ClickPoints.generate (wStart, wFinish)
+      val yClickPoints = ClickPoints.generate (hStart, hFinish)
+    in
+      { triangles = []
+      , triangleStage = NO_TRIANGLE
+      , windowWidth = windowWidth
+      , windowHeight = windowHeight
+      , xClickPoints = xClickPoints
+      , yClickPoints = yClickPoints
+      , undo = []
+      , redo = []
+      , mouseX = 0.0
+      , mouseY = 0.0
+      , showGraph = true
+      }
+    end
+
+  fun fromWindowWidthAndHeight (windowWidth, windowHeight) =
+    if windowWidth = windowHeight then
+      helpFromWidthAndHeight
+        (windowWidth, windowHeight, 0, windowWidth, 0, windowHeight)
+    else if windowWidth > windowHeight then
+      let
+        val difference = windowWidth - windowHeight
+        val wStart = difference div 2
+        val wFinish = wStart + windowHeight
+      in
+        helpFromWidthAndHeight
+          (windowWidth, windowHeight, wStart, wFinish, 0, windowHeight)
+      end
+    else
+      let
+        val difference = windowHeight - windowWidth
+        val hStart = difference div 2
+        val hFinish = hStart + windowWidth
+      in
+        helpFromWidthAndHeight
+          (windowWidth, windowHeight, 0, windowWidth, hStart, hFinish)
+      end
+end