new hat block for "when this scene starts"

HISTORY.md

@@ -35,6 +35,7 @@
 
 ### 2021-09-08
 * objects: changed category for "switch to scene" to control
+* blocks, objects, threads: new hat block for "when this scene starts"
 
 ### 2021-09-07
 * blocks, objects, threads: new change-of-scene event

snap.html

@@ -16,8 +16,8 @@
         <script src="src/morphic.js?version=2021-07-09"></script>
         <script src="src/symbols.js?version=2021-03-03"></script>
         <script src="src/widgets.js?version=2021-07-21"></script>
-        <script src="src/blocks.js?version=2021-09-07"></script>
-        <script src="src/threads.js?version=2021-09-07"></script>
+        <script src="src/blocks.js?version=2021-09-08"></script>
+        <script src="src/threads.js?version=2021-09-08"></script>
         <script src="src/objects.js?version=2021-09-08"></script>
         <script src="src/scenes.js?version=2021-07-21"></script>
         <script src="src/gui.js?version=2021-09-07"></script>

src/blocks.js

@@ -160,7 +160,7 @@ CustomCommandBlockMorph, ToggleButtonMorph, DialMorph, SnapExtensions*/
 
 // Global stuff ////////////////////////////////////////////////////////
 
-modules.blocks = '2021-September-07';
+modules.blocks = '2021-September-08';
 
 var SyntaxElementMorph;
 var BlockMorph;
@@ -416,8 +416,7 @@ SyntaxElementMorph.prototype.labelParts = {
             'mouse-departed' : ['mouse-departed'],
             'scrolled-up' : ['scrolled-up'],
             'scrolled-down' : ['scrolled-down'],
-            'stopped' : ['stopped'], // experimental
-            'entering a scene' : ['entering a scene'] // experimental
+            'stopped' : ['stopped'] // experimental
         }
     },
     '%dates': {
@@ -3158,6 +3157,8 @@ BlockMorph.prototype.showMessageUsers = function () {
         message = '__shout__go__';
     } else if (this.selector === 'receiveOnClone') {
         message = '__clone__init__';
+    } else if (this.selector === 'receiveOnScene') {
+        message = '__scene__init__';
     } else if (inputs[0] instanceof InputSlotMorph) {
         message = inputs[0].evaluate();
     }

src/objects.js

@@ -903,6 +903,11 @@ SpriteMorph.prototype.initBlocks = function () {
         },
 
         // Scenes
+        receiveOnScene: {
+            type: 'hat',
+            category: 'control',
+            spec: 'when this scene starts'
+        },
         doSwitchToScene: {
             type: 'command',
             category: 'control',
@@ -2507,8 +2512,8 @@ SpriteMorph.prototype.blockTemplates = function (category = 'motion') {
         blocks.push(block('receiveKey'));
         blocks.push(block('receiveInteraction'));
         blocks.push(block('receiveCondition'));
-        blocks.push(block('receiveMessage'));
         blocks.push('-');
+        blocks.push(block('receiveMessage'));
         blocks.push(block('doBroadcast'));
         blocks.push(block('doBroadcastAndWait'));
         blocks.push(block('doSend'));
@@ -2547,9 +2552,10 @@ SpriteMorph.prototype.blockTemplates = function (category = 'motion') {
         blocks.push(block('newClone'));
         blocks.push(block('removeClone'));
         blocks.push('-');
-        blocks.push(block('doPauseAll'));
-        blocks.push('-');
+        blocks.push(block('receiveOnScene'));
         blocks.push(block('doSwitchToScene'));
+        blocks.push('-');
+        blocks.push(block('doPauseAll'));
 
     } else if (category === 'sensing') {
 
@@ -6092,6 +6098,9 @@ SpriteMorph.prototype.allHatBlocksFor = function (message) {
             if (morph.selector === 'receiveOnClone') {
                 return message === '__clone__init__';
             }
+            if (morph.selector === 'receiveOnScene') {
+                return message === '__scene__init__';
+            }
         }
         return false;
     });
@@ -8438,9 +8447,7 @@ StageMorph.prototype.fireChangeOfSceneEvent = function () {
 
     this.children.concat(this).forEach(morph => {
         if (isSnapObject(morph)) {
-            morph.allHatBlocksForInteraction(
-                'entering a scene'
-            ).forEach(block =>
+            morph.allHatBlocksFor('__scene__init__').forEach(block =>
                 procs.push(this.threads.startProcess(
                     block,
                     morph,
@@ -8716,8 +8723,8 @@ StageMorph.prototype.blockTemplates = function (category = 'motion') {
         blocks.push(block('receiveKey'));
         blocks.push(block('receiveInteraction'));
         blocks.push(block('receiveCondition'));
-        blocks.push(block('receiveMessage'));
         blocks.push('-');
+        blocks.push(block('receiveMessage'));
         blocks.push(block('doBroadcast'));
         blocks.push(block('doBroadcastAndWait'));
         blocks.push(block('doSend'));
@@ -8754,9 +8761,10 @@ StageMorph.prototype.blockTemplates = function (category = 'motion') {
         blocks.push(block('createClone'));
         blocks.push(block('newClone'));
         blocks.push('-');
-        blocks.push(block('doPauseAll'));
-        blocks.push('-');
+        blocks.push(block('receiveOnScene'));
         blocks.push(block('doSwitchToScene'));
+        blocks.push('-');
+        blocks.push(block('doPauseAll'));
 
     } else if (category === 'sensing') {
 

src/threads.js

@@ -64,7 +64,7 @@ SnapExtensions, AlignmentMorph, TextMorph, Cloud*/
 
 /*jshint esversion: 6*/
 
-modules.threads = '2021-September-07';
+modules.threads = '2021-September-08';
 
 var ThreadManager;
 var Process;