new feature: enable sprite nesting via the context menu

HISTORY.md

@@ -13,6 +13,7 @@
     * blocks for changing and querying the "flat line ends" setting 
     * selectors for changing and querying "draggable" and "rotation style" settings
     * special context-aware drop-downs for custom blocks
+    * new "stick to" submenu in the sprite context menu where applicable
     * multi-line and monospaced "code" input slots for custom blocks
     * new "string" library, thanks, Brian
     * added "neg" selector to monadic function reporter in "Operators" category
@@ -39,6 +40,9 @@
     * Greek, thanks, Alexandros!
     * German
 
+### 2019-02-18
+* Objects: enable sprite nesting via the context menu
+
 ### 2019-02-15
 * BYOB: tweaked yesterday's fix...
 * Blocks: fixed a glitch in the custom block help mechanism (show only the prototype)

snap.html

@@ -8,7 +8,7 @@
         <script type="text/javascript" src="src/widgets.js?version=2018-10-02"></script>
         <script type="text/javascript" src="src/blocks.js?version=2019-02-15"></script>
         <script type="text/javascript" src="src/threads.js?version=2019-01-28"></script>
-        <script type="text/javascript" src="src/objects.js?version=2019-02-07"></script>
+        <script type="text/javascript" src="src/objects.js?version=2019-02-18"></script>
         <script type="text/javascript" src="src/gui.js?version=2019-02-07"></script>
         <script type="text/javascript" src="src/paint.js?version=2018-10-02"></script>
         <script type="text/javascript" src="src/lists.js?version=2019-02-07"></script>

src/objects.js

@@ -83,7 +83,7 @@ BlockEditorMorph, BlockDialogMorph, PrototypeHatBlockMorph, localize,
 TableMorph, TableFrameMorph, normalizeCanvas, BooleanSlotMorph, HandleMorph,
 AlignmentMorph, Process, XML_Element, VectorPaintEditorMorph*/
 
-modules.objects = '2019-February-07';
+modules.objects = '2019-February-18';
 
 var SpriteMorph;
 var StageMorph;
@@ -3206,7 +3206,9 @@ SpriteMorph.prototype.reportSounds = function () {
 
 SpriteMorph.prototype.userMenu = function () {
     var ide = this.parentThatIsA(IDE_Morph),
-        menu = new MenuMorph(this);
+        menu = new MenuMorph(this),
+        allParts,
+        anchors;
 
     if (ide && ide.isAppMode) {
         // menu.addItem('help', 'nop');
@@ -3246,6 +3248,15 @@ SpriteMorph.prototype.userMenu = function () {
             localize('detach from') + ' ' + this.anchor.name,
             'detachFromAnchor'
         );
+    } else {
+        allParts = this.allParts();
+        anchors = this.parent.children.filter(function (morph) {
+            return morph instanceof SpriteMorph &&
+                !contains(allParts, morph);
+        });
+        if (anchors.length) {
+            menu.addMenu('stick to', this.anchorsMenu(anchors));
+        }
     }
     if (this.parts.length) {
         menu.addItem('detach all parts', 'detachAllParts');
@@ -3254,6 +3265,20 @@ SpriteMorph.prototype.userMenu = function () {
     return menu;
 };
 
+SpriteMorph.prototype.anchorsMenu = function (targets) {
+    var menu = new MenuMorph(this.attachTo, null, this);
+    targets.forEach(function (sprite) {
+        menu.addItem(
+            [
+                sprite.thumbnail(new Point(24, 24)),
+                sprite.name,
+            ],
+            sprite
+        );
+    });
+    return menu;
+};
+
 SpriteMorph.prototype.exportSprite = function () {
     if (this.isTemporary) {return; }
     var ide = this.parentThatIsA(IDE_Morph);
@@ -5987,6 +6012,10 @@ SpriteMorph.prototype.booleanMorph = function (bool) {
     simulate Morphic trees
 */
 
+SpriteMorph.prototype.attachTo = function (aSprite) {
+    aSprite.attachPart(this);
+};
+
 SpriteMorph.prototype.attachPart = function (aSprite) {
     var v = Date.now();
     if (aSprite.anchor) {