Add a block container for monitors that will run in the sequencer

src/engine/blocks.js

@@ -273,16 +273,22 @@ class Blocks {
      */
     changeBlock (args) {
         // Validate
-        if (args.element !== 'field' && args.element !== 'mutation') return;
+        if (['field', 'mutation', 'checkbox'].indexOf(args.element) === -1) return;
         const block = this._blocks[args.id];
         if (typeof block === 'undefined') return;
 
-        if (args.element === 'field') {
+        switch (args.element) {
+        case 'field':
             // Update block value
             if (!block.fields[args.name]) return;
             block.fields[args.name].value = args.value;
-        } else if (args.element === 'mutation') {
+            break;
+        case 'mutation':
             block.mutation = mutationAdapter(args.value);
+            break;
+        case 'checkbox':
+            block.isMonitored = args.value;
+            break;
         }
     }
 
@@ -342,6 +348,20 @@ class Blocks {
         }
     }
 
+    
+    /**
+     * Block management: run all blocks.
+     * @param {!object} runtime Runtime to run all blocks in.
+     */
+    runAllMonitored (runtime) {
+        Object.keys(this._blocks).forEach(blockId => {
+            if (this.getBlock(blockId).isMonitored) {
+                // @todo handle specific targets (e.g. apple x position)
+                runtime.toggleScript(blockId);
+            }
+        });
+    }
+
     /**
      * Block management: delete blocks and their associated scripts.
      * @param {!object} e Blockly delete event to be processed.

src/engine/runtime.js

@@ -52,6 +52,13 @@ class Runtime extends EventEmitter {
          */
         this.flyoutBlocks = new Blocks();
 
+        /**
+         * Storage container for monitor blocks.
+         * These will execute on a target maybe
+         * @type {!Blocks}
+         */
+        this.monitorBlocks = new Blocks();
+
         /**
          * Currently known editing target for the VM.
          * @type {?Target}
@@ -416,8 +423,9 @@ class Runtime extends EventEmitter {
     /**
      * Toggle a script.
      * @param {!string} topBlockId ID of block that starts the script.
+     * @param {?string} optTarget target ID for target to run script on. If not supplied, uses editing target.
      */
-    toggleScript (topBlockId) {
+    toggleScript (topBlockId, optTarget) {
         // Remove any existing thread.
         for (let i = 0; i < this.threads.length; i++) {
             if (this.threads[i].topBlock === topBlockId) {
@@ -426,7 +434,7 @@ class Runtime extends EventEmitter {
             }
         }
         // Otherwise add it.
-        this._pushThread(topBlockId, this._editingTarget);
+        this._pushThread(topBlockId, optTarget ? optTarget : this._editingTarget);
     }
 
     /**
@@ -632,6 +640,7 @@ class Runtime extends EventEmitter {
             }
         }
         this.redrawRequested = false;
+        this._pushMonitors();
         const doneThreads = this.sequencer.stepThreads();
         this._updateGlows(doneThreads);
         this._setThreadCount(this.threads.length + doneThreads.length);
@@ -641,6 +650,13 @@ class Runtime extends EventEmitter {
         }
     }
 
+    /**
+     * Queue monitor blocks to sequencer to be run.
+     */
+    _pushMonitors () {
+        this.monitorBlocks.runAllMonitored(this);
+    }
+
     /**
      * Set the current editing target known by the runtime.
      * @param {!Target} editingTarget New editing target.

src/engine/target.js

@@ -20,7 +20,7 @@ class Target extends EventEmitter {
         super();
 
         if (!blocks) {
-            blocks = new Blocks(this);
+            blocks = new Blocks();
         }
         /**
          * A unique ID for this target.

src/playground/playground.js

@@ -92,6 +92,7 @@ window.onload = function () {
     workspace.addChangeListener(vm.blockListener);
     const flyoutWorkspace = workspace.getFlyout().getWorkspace();
     flyoutWorkspace.addChangeListener(vm.flyoutBlockListener);
+    flyoutWorkspace.addChangeListener(vm.monitorBlockListener);
 
     // Create FPS counter.
     const stats = new window.Stats();

src/virtual-machine.js

@@ -58,6 +58,7 @@ class VirtualMachine extends EventEmitter {
 
         this.blockListener = this.blockListener.bind(this);
         this.flyoutBlockListener = this.flyoutBlockListener.bind(this);
+        this.monitorBlockListener = this.monitorBlockListener.bind(this);
     }
 
     /**
@@ -344,6 +345,16 @@ class VirtualMachine extends EventEmitter {
         this.runtime.flyoutBlocks.blocklyListen(e, this.runtime);
     }
 
+    /**
+     * Handle a Blockly event for the flyout to be passed to the monitor container.
+     * @param {!Blockly.Event} e Any Blockly event.
+     */
+    monitorBlockListener (e) {
+        if (['create', 'change'].indexOf(e.type) !== -1) {
+            this.runtime.monitorBlocks.blocklyListen(e, this.runtime);
+        }
+    }
+
     /**
      * Set an editing target. An editor UI can use this function to switch
      * between editing different targets, sprites, etc.