Prototypal inheritance of sprite-local variables

(experimental) slotwise inheritance à la Henry Lieberman for
sprite-local variables.

see
http://web.media.mit.edu/~lieber/Lieberary/OOP/Delegation/Delegation.htm
l

Let a sprite inherit another sprite’s local variables by making it the
“parent” in the sprite-icon’s context menu (the button icon in the
sprite corral underneath the stage). The child not only inherits the
variable slot but also - dynamically - the parent variable’s value.
Changing the parent’s variable value also changes it for every child.
If a child uses SET or CHANGE on an inherited variable it automatically
“shadows” it with its own value, thereby stopping dynamic participation
in the parent slot’s value (in effect dis-inheriting that slot).
Deleting a shadowed variable slot once again reinstates its inheritance
status.

inherited variables are shown as “ghosted” both in the child’s
variables palette and in such stage watchers. “Shadowing” them
un-ghosts both the variable blob template in the palette and the
watcher onstage (if any). Deleting a shadowed variable once again
ghosts the watcher and the palette block template.

Delete a (shadowed) variable either via the “Delete a variable” button
in the IDE or using the new “Delete” block in the variables category

1 files changed, 6 insertions, 5 deletions

diff --git a/widgets.js b/widgets.js
index bb250a8..b52782b 100644
--- a/widgets.js
+++ b/widgets.js
@@ -7,7 +7,7 @@
     written by Jens Mönig
     jens@moenig.org
 
-    Copyright (C) 2014 by Jens Mönig
+    Copyright (C) 2015 by Jens Mönig
 
     This file is part of Snap!.
 
@@ -74,7 +74,7 @@ HTMLCanvasElement, fontHeight, SymbolMorph, localize, SpeechBubbleMorph,
 ArrowMorph, MenuMorph, isString, isNil, SliderMorph, MorphicPreferences,
 ScrollFrameMorph*/
 
-modules.widgets = '2014-February-13';
+modules.widgets = '2015-March-21';
 
 var PushButtonMorph;
 var ToggleButtonMorph;
@@ -493,7 +493,7 @@ function ToggleButtonMorph(
     labelString,
     query, // predicate/selector
     environment,
-    hint,
+    hint, // optional, String or Function
     template, // optional, for cached background images
     minWidth, // <num> optional, if specified label will left-align
     hasPreview, // <bool> show press color on left edge (e.g. category)
@@ -560,12 +560,13 @@ ToggleButtonMorph.prototype.init = function (
 // ToggleButtonMorph events
 
 ToggleButtonMorph.prototype.mouseEnter = function () {
+    var contents = this.hint instanceof Function ? this.hint() : this.hint;
     if (!this.state) {
         this.image = this.highlightImage;
         this.changed();
     }
-    if (this.hint) {
-        this.bubbleHelp(this.hint);
+    if (contents) {
+        this.bubbleHelp(contents);
     }
 };