Fixed #44

Circularity no longer breaks watchers

history.txt

@@ -1653,3 +1653,7 @@ ______
 130422
 ------
 * GUI: Double clicking support for cloud side of project dialog
+
+130423
+------
+* Lists, Objects: Circularity no longer breaks watchers

lists.js

@@ -61,7 +61,7 @@ PushButtonMorph, SyntaxElementMorph, Color, Point, WatcherMorph,
 StringMorph, SpriteMorph, ScrollFrameMorph, CellMorph, ArrowMorph,
 MenuMorph, snapEquals, Morph, isNil, localize*/
 
-modules.lists = '2013-April-12';
+modules.lists = '2013-April-23';
 
 var List;
 var ListWatcherMorph;
@@ -345,11 +345,11 @@ ListWatcherMorph.prototype.cellColor =
 
 // ListWatcherMorph instance creation:
 
-function ListWatcherMorph(list) {
-    this.init(list);
+function ListWatcherMorph(list, parentCell) {
+    this.init(list, parentCell);
 }
 
-ListWatcherMorph.prototype.init = function (list) {
+ListWatcherMorph.prototype.init = function (list, parentCell) {
     var myself = this;
 
     this.list = list || new List();
@@ -357,6 +357,7 @@ ListWatcherMorph.prototype.init = function (list) {
     this.range = 100;
     this.lastUpdated = Date.now();
     this.lastCell = null;
+    this.parentCell = parentCell || null; // for circularity detection
 
     // elements declarations
     this.label = new StringMorph(
@@ -434,6 +435,7 @@ ListWatcherMorph.prototype.update = function (anyway) {
         starttime, maxtime = 1000;
 
     this.frame.contents.children.forEach(function (m) {
+
         if (m instanceof CellMorph
                 && m.contentsMorph instanceof ListWatcherMorph) {
             m.contentsMorph.update();
@@ -529,7 +531,8 @@ ListWatcherMorph.prototype.update = function (anyway) {
             cell = new CellMorph(
                 this.list.at(idx),
                 this.cellColor,
-                idx
+                idx,
+                this.parentCell
             );
             button = new PushButtonMorph(
                 this.list.remove,

objects.js

@@ -120,7 +120,7 @@ PrototypeHatBlockMorph*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.objects = '2013-April-19';
+modules.objects = '2013-April-23';
 
 var SpriteMorph;
 var StageMorph;
@@ -4805,16 +4805,17 @@ CellMorph.uber = BoxMorph.prototype;
 
 // CellMorph instance creation:
 
-function CellMorph(contents, color, idx) {
-    this.init(contents, color, idx);
+function CellMorph(contents, color, idx, parentCell) {
+    this.init(contents, color, idx, parentCell);
 }
 
-CellMorph.prototype.init = function (contents, color, idx) {
+CellMorph.prototype.init = function (contents, color, idx, parentCell) {
     this.contents = (contents === 0 ? 0
             : contents === false ? false
                     : contents || '');
     this.isEditable = isNil(idx) ? false : true;
     this.idx = idx || null; // for list watchers
+    this.parentCell = parentCell || null; // for list circularity detection
     CellMorph.uber.init.call(
         this,
         SyntaxElementMorph.prototype.corner,
@@ -4842,6 +4843,17 @@ CellMorph.prototype.normal = function () {
     this.changed();
 };
 
+// CellMorph circularity testing:
+
+
+CellMorph.prototype.isCircular = function (list) {
+    if (!this.parentCell) {return false; }
+    if (list instanceof List) {
+        return this.contents === list || this.parentCell.isCircular(list);
+    }
+    return this.parentCell.isCircular(this.contents);
+};
+
 // CellMorph layout:
 
 CellMorph.prototype.fixLayout = function () {
@@ -4914,8 +4926,23 @@ CellMorph.prototype.drawNew = function () {
             this.contentsMorph.silentSetHeight(img.height);
             this.contentsMorph.image = img;
         } else if (this.contents instanceof List) {
-            this.contentsMorph = new ListWatcherMorph(this.contents);
-            this.contentsMorph.isDraggable = false;
+            if (this.isCircular()) {
+                this.contentsMorph = new TextMorph(
+                    '(...)',
+                    fontSize,
+                    null,
+                    false, // bold
+                    true, // italic
+                    'center'
+                );
+                this.contentsMorph.setColor(new Color(255, 255, 255));
+            } else {
+                this.contentsMorph = new ListWatcherMorph(
+                    this.contents,
+                    this
+                );
+                this.contentsMorph.isDraggable = false;
+            }
         } else {
             this.contentsMorph = new TextMorph(
                 !isNil(this.contents) ? this.contents.toString() : '',