Merge pull request #30 from vishesh/master

Implement stop-with #23

whalesong/world.rkt

@@ -1,4 +1,5 @@
 #lang s-exp "lang/base.rkt"
+
 (require "world/main.rkt")
 
 (provide (all-from-out "world/main.rkt"))

whalesong/world/impl.rkt

@@ -0,0 +1,27 @@
+#lang s-exp "../lang/js/js.rkt"
+
+(require "../image.rkt"
+         "types.rkt")
+
+(declare-implementation
+ #:racket "racket-impl.rkt"
+ #:javascript (
+               ;; the raw implementation doesn't know anything about
+               ;; Whalesong.
+               "raw-jsworld.js"  
+
+               ;; We add Whalesong-specific things here.
+               "kernel.js"
+               "js-impl.js"
+               )
+ #:provided-values (big-bang
+                    on-tick
+                    on-key
+                    on-release
+                    on-mouse
+                    key=?
+                    to-draw
+                    stop-when))
+
+
+

whalesong/world/js-impl.js

@@ -32,7 +32,10 @@ var checkHandler = plt.baselib.check.makeCheckArgumentType(
     isWorldConfigOption,
     "world configuration handler");
 
-
+var worldNamespace = MACHINE.modules['whalesong/world/types.rkt'].getExternalExports();
+var stopWithStruct = worldNamespace.get('struct:stop-with');
+var isStopWithStruct = stopWithStruct.predicate
+var stopWithWorld = function(s) { return stopWithStruct.accessor(s, 0); }
 
 
 // The default tick delay is 28 times a second.

whalesong/world/main.rkt

@@ -1,26 +1,7 @@
-#lang s-exp "../lang/js/js.rkt"
-
-(require "../image.rkt")
-
-(declare-implementation
- #:racket "racket-impl.rkt"
- #:javascript (
-               ;; the raw implementation doesn't know anything about
-               ;; Whalesong.
-               "raw-jsworld.js"  
-
-               ;; We add Whalesong-specific things here.
-               "kernel.js"
-               "js-impl.js"
-               )
- #:provided-values (big-bang
-                    on-tick
-                    on-key
-                    on-release
-                    on-mouse
-                    key=?
-                    to-draw
-                    stop-when))
-
+#lang s-exp "../lang/base.rkt"
 
+(require "impl.rkt"
+         "types.rkt")
 
+(provide (all-from-out "impl.rkt")
+         (all-from-out "types.rkt"))

whalesong/world/racket-impl.rkt

@@ -1,5 +1,7 @@
 #lang s-exp "../lang/base.rkt"
 
+(require "types.rkt")
+
 (provide big-bang
          to-draw
          on-tick

whalesong/world/raw-jsworld.js

@@ -99,6 +99,10 @@ var rawJsworld = {};
 
 
 
+    function add_world_listener_first(listener) {
+        worldListeners.unshift(listener);
+    }
+
     function add_world_listener(listener) {
         worldListeners.push(listener);
     }
@@ -659,25 +663,47 @@ var rawJsworld = {};
                 handlers[i].onRegister(top);
             }
         }
-        var watchForTermination = function(w, oldW, k2) {
-            stopWhen.test(w,
-                          function(stop) {
-                              if (stop) {
+
+        var showLastPicture = function(w, oldW) {
             if (stopWhen.last_picture_handler) {
                 var handler = stopWhen.last_picture_handler();
                 handler.onRegister(top);
                 handler._listener(w, oldW, function(v) {
                     Jsworld.shutdown({cleanShutdown: true});
-                                          k2();
                 })
             } else {
                 Jsworld.shutdown({cleanShutdown: true});
             }
-                              } else { k2(); }
+        };
+
+        var watchForTermination = function(w, oldW, k2) {
+            stopWhen.test(w,
+                function(stop) {
+                    if (stop) {
+                        showLastPicture(w, oldW);
+                    }
+                    k2();
                 });
         };
         add_world_listener(watchForTermination);
 
+        var watchForStopWith = function(w, oldW, k2) {
+            /**
+             * If we have a  last_picture we call that with new world, or
+             * else call the regular draw handler
+             *
+             * TODO: We don't call regular draw handler as of now when
+             *       when world ends with stop-with
+             */
+            if (isStopWithStruct(w)) {
+                world = stopWithWorld(w); //NOTE: Is this assignment safe?
+                showLastPicture(world, oldW);
+            }
+            k2();
+        }
+        /* Its important that this stays above all handlers, so that we
+         * shutdown before calling any other handler */
+        add_world_listener_first(watchForStopWith);
 
         // Finally, begin the big-bang.
         copy_attribs(top, attribs);

whalesong/world/types.rkt

@@ -0,0 +1,5 @@
+#lang s-exp "../lang/base.rkt"
+
+(provide (struct-out stop-with))
+
+(define-struct stop-with (world))