From 5e484fb2d53bfdaa4394ada4927d80a91008d600 Mon Sep 17 00:00:00 2001
From: "Kartik K. Agaram" <vc@akkartik.com>
Date: Sun, 16 May 2021 08:05:26 -0700
Subject: [PATCH] .

---
 ex11.mu | 73 ++++++++++++++++++++++++++++++++++++++++-----------------
 1 file changed, 52 insertions(+), 21 deletions(-)

diff --git a/ex11.mu b/ex11.mu
index 246a13a8..9b11c606 100644
--- a/ex11.mu
+++ b/ex11.mu
@@ -1,16 +1,17 @@
 # Demo of an interactive app: controlling a Bezier curve on screen
 
 fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
-  var p0-storage: point
-  var p0/ecx: (addr point) <- address p0-storage
-  initialize-point p0, 5 5
-  var p1-storage: point
-  var p1/edx: (addr point) <- address p1-storage
-  initialize-point p1, 0x80 0x100
-  var p2-storage: point
-  var p2/ebx: (addr point) <- address p2-storage
-  initialize-point p2, 0x200 0x140
-  render screen, p0, p1, p2
+  var env-storage: environment
+  var env/esi: (addr environment) <- address env-storage
+  initialize-environment env, 5 5, 0x80 0x100, 0x200 0x140
+  render screen, env
+}
+
+type environment {
+  p0: (handle point)
+  p1: (handle point)
+  p2: (handle point)
+  cursor: (handle point)  # one of p0, p1 or p2
 }
 
 type point {
@@ -18,17 +19,17 @@ type point {
   y: int
 }
 
-fn initialize-point _p: (addr point), x: int, y: int {
-  var p/esi: (addr point) <- copy _p
-  var dest/eax: (addr int) <- get p, x
-  var src/ecx: int <- copy x
-  copy-to *dest, src
-  dest <- get p, y
-  src <- copy y
-  copy-to *dest, src
-}
-
-fn render screen: (addr screen), p0: (addr point), p1: (addr point), p2: (addr point) {
+fn render screen: (addr screen), _self: (addr environment) {
+  var self/esi: (addr environment) <- copy _self
+  var tmp-ah/ecx: (addr handle point) <- get self, p0
+  var tmp/eax: (addr point) <- lookup *tmp-ah
+  var p0/ebx: (addr point) <- copy tmp
+  tmp-ah <- get self, p1
+  tmp <- lookup *tmp-ah
+  var p1/edx: (addr point) <- copy tmp
+  tmp-ah <- get self, p2
+  tmp <- lookup *tmp-ah
+  var p2/ecx: (addr point) <- copy tmp
   # control lines
   line    screen, p0, p1,                 7/color
   line    screen, p1, p2,                 7/color
@@ -69,3 +70,33 @@ fn disc screen: (addr screen), _p: (addr point), radius: int, color: int, border
   var y/edx: (addr int) <- get p, y
   draw-disc screen, *x *y, radius, color, border-color
 }
+
+fn initialize-environment _self: (addr environment), x0: int, y0: int, x1: int, y1: int, x2: int, y2: int {
+  var self/esi: (addr environment) <- copy _self
+  var p0-ah/eax: (addr handle point) <- get self, p0
+  allocate p0-ah
+  var p0/eax: (addr point) <- lookup *p0-ah
+  initialize-point p0, x0 y0
+  var p1-ah/eax: (addr handle point) <- get self, p1
+  allocate p1-ah
+  var p1/eax: (addr point) <- lookup *p1-ah
+  initialize-point p1, x1 y1
+  var p2-ah/eax: (addr handle point) <- get self, p2
+  allocate p2-ah
+  var p2/eax: (addr point) <- lookup *p2-ah
+  initialize-point p2, x2 y2
+  # cursor initially at p0
+  var cursor-ah/edi: (addr handle point) <- get self, cursor
+  var src-ah/esi: (addr handle point) <- get self, p0
+  copy-object src-ah, cursor-ah
+}
+
+fn initialize-point _p: (addr point), x: int, y: int {
+  var p/esi: (addr point) <- copy _p
+  var dest/eax: (addr int) <- get p, x
+  var src/ecx: int <- copy x
+  copy-to *dest, src
+  dest <- get p, y
+  src <- copy y
+  copy-to *dest, src
+}