Add mechanism for per-block metadata

src/engine/runtime.js

@@ -23,6 +23,12 @@ function Runtime () {
      */
     this.blocks = {};
 
+    /**
+     * Primitive-accessible execution metadata for each block.
+     * @type {Object.<string, Object>}
+     */
+    this.blockExecutionData = {};
+
     /**
      * All stacks in the workspace.
      * A list of block IDs that represent stacks (first block in stack).
@@ -90,6 +96,7 @@ Runtime.THREAD_STEP_INTERVAL = 1000 / 60;
 Runtime.prototype.createBlock = function (block, opt_isFlyoutBlock) {
     // Create new block
     this.blocks[block.id] = block;
+    this.blockExecutionData[block.id] = {};
 
     // Walk each field and add any shadow blocks
     // @todo Expand this to cover vertical / nested blocks
@@ -98,6 +105,7 @@ Runtime.prototype.createBlock = function (block, opt_isFlyoutBlock) {
         for (var y in shadows) {
             var shadow = shadows[y];
             this.blocks[shadow.id] = shadow;
+            this.blockExecutionData[shadow.id] = {};
         }
     }
 
@@ -194,6 +202,7 @@ Runtime.prototype.deleteBlock = function (e) {
 
     // Delete block
     delete this.blocks[e.id];
+    delete this.blockExecutionData[e.id];
 };
 
 // -----------------------------------------------------------------------------
@@ -377,4 +386,24 @@ Runtime.prototype._getOpcode = function (id) {
     return this.blocks[id].opcode;
 };
 
+/**
+ * Set block execution data
+ * @param {!string} id Block ID
+ * @param {!Any} key Data key
+ * @param {?Any} value Data value
+ */
+Runtime.prototype.setBlockExecutionData = function (id, key, value) {
+    this.blockExecutionData[id][key] = value;
+};
+
+/**
+ * Get block execution data
+ * @param {!string} id Block ID
+ * @param {!Any} key Data key
+ * @return {?Any} Data value
+ */
+Runtime.prototype.getBlockExecutionData = function (id, key) {
+    return this.blockExecutionData[id][key];
+};
+
 module.exports = Runtime;

src/engine/sequencer.js

@@ -110,6 +110,22 @@ Sequencer.prototype.stepThread = function (thread) {
         instance.runtime.glowBlock(currentBlock, false);
     };
 
+    /**
+     * A callback for the primitive to set data on the block level.
+     * @type {Function}
+     */
+    var blockDataSetCallback = function (key, value) {
+        instance.runtime.setBlockExecutionData(currentBlock, key, value);
+    };
+
+    /**
+     * A callback for the primitive to get data on the block level.
+     * @type {Function}
+     */
+    var blockDataGetCallback = function (key) {
+        return instance.runtime.getBlockExecutionData(currentBlock, key);
+    };
+
     // @todo
     var argValues = [];
 
@@ -128,7 +144,9 @@ Sequencer.prototype.stepThread = function (thread) {
                 blockFunction(argValues, {
                     yield: threadYieldCallback,
                     done: threadDoneCallback,
-                    timeout: YieldTimers.timeout
+                    timeout: YieldTimers.timeout,
+                    setData: blockDataSetCallback,
+                    getData: blockDataGetCallback
                 });
             }
             catch(e) {