Merge pull request #12 from cwillisf/feature/execute-blocks

Allow the Sequencer to execute a JS function for each block

.eslintrc

@@ -7,7 +7,8 @@
         "linebreak-style": [2, "unix"],
         "max-len": [2, 80, 4],
         "semi": [2, "always"],
-        "strict": [2, "never"]
+        "strict": [2, "never"],
+        "no-console": [2, {"allow": ["log", "warn", "error"]}]
     },
     "env": {
         "node": true,

src/blocks/scratch3.js

@@ -0,0 +1,54 @@
+
+function Scratch3Blocks(runtime) {
+    /**
+     * The runtime instantiating this block package.
+     * @type {Runtime}
+     */
+    this.runtime = runtime;
+}
+
+/**
+ * Retrieve the block primitives implemented by this package.
+ * @return {Object.<string, Function>} Mapping of opcode to Function.
+ */
+Scratch3Blocks.prototype.getPrimitives = function() {
+    return {
+        'control_repeat': this.repeat,
+        'control_forever': this.forever,
+        'control_wait': this.wait,
+        'control_stop': this.stop,
+        'event_whenflagclicked': this.whenFlagClicked,
+        'event_whenbroadcastreceived': this.whenBroadcastReceived,
+        'event_broadcast': this.broadcast
+    };
+};
+
+Scratch3Blocks.prototype.repeat = function() {
+    console.log('Running: control_repeat');
+};
+
+Scratch3Blocks.prototype.forever = function() {
+    console.log('Running: control_forever');
+};
+
+Scratch3Blocks.prototype.wait = function() {
+    console.log('Running: control_wait');
+};
+
+Scratch3Blocks.prototype.stop = function() {
+    console.log('Running: control_stop');
+};
+
+Scratch3Blocks.prototype.whenFlagClicked = function() {
+    console.log('Running: event_whenflagclicked');
+};
+
+Scratch3Blocks.prototype.whenBroadcastReceived = function() {
+    console.log('Running: event_whenbroadcastreceived');
+};
+
+Scratch3Blocks.prototype.broadcast = function() {
+    console.log('Running: event_broadcast');
+};
+
+module.exports = Scratch3Blocks;

src/blocks/wedo2.js

@@ -0,0 +1,49 @@
+
+function WeDo2Blocks(runtime) {
+    /**
+     * The runtime instantiating this block package.
+     * @type {Runtime}
+     */
+    this.runtime = runtime;
+}
+
+/**
+ * Retrieve the block primitives implemented by this package.
+ * @return {Object.<string, Function>} Mapping of opcode to Function.
+ */
+WeDo2Blocks.prototype.getPrimitives = function() {
+    return {
+        'wedo_motorclockwise': this.motorClockwise,
+        'wedo_motorcounterclockwise': this.motorCounterClockwise,
+        'wedo_motorspeed': this.motorSpeed,
+        'wedo_setcolor': this.setColor,
+        'wedo_whendistanceclose': this.whenDistanceClose,
+        'wedo_whentilt': this.whenTilt
+    };
+};
+
+WeDo2Blocks.prototype.motorClockwise = function() {
+    console.log('Running: wedo_motorclockwise');
+};
+
+WeDo2Blocks.prototype.motorCounterClockwise = function() {
+    console.log('Running: wedo_motorcounterclockwise');
+};
+
+WeDo2Blocks.prototype.motorSpeed = function() {
+    console.log('Running: wedo_motorspeed');
+};
+
+WeDo2Blocks.prototype.setColor = function() {
+    console.log('Running: wedo_setcolor');
+};
+
+WeDo2Blocks.prototype.whenDistanceClose = function() {
+    console.log('Running: wedo_whendistanceclose');
+};
+
+WeDo2Blocks.prototype.whenTilt = function() {
+    console.log('Running: wedo_whentilt');
+};
+
+module.exports = WeDo2Blocks;

src/engine/runtime.js

@@ -3,6 +3,11 @@ var Sequencer = require('./sequencer');
 var Thread = require('./thread');
 var util = require('util');
 
+var defaultBlockPackages = {
+    'scratch3': require('../blocks/scratch3'),
+    'wedo2': require('../blocks/wedo2')
+};
+
 /**
  * Manages blocks, stacks, and the sequencer.
  */
@@ -34,6 +39,14 @@ function Runtime () {
 
     /** @type {!Sequencer} */
     this.sequencer = new Sequencer(this);
+
+    /**
+     * Map to look up a block primitive's implementation function by its opcode.
+     * This is a two-step lookup: package name first, then primitive name.
+     * @type {Object.<string, Function>}
+     */
+    this._primitives = {};
+    this._registerBlockPackages();
 }
 
 /**
@@ -184,6 +197,39 @@ Runtime.prototype.deleteBlock = function (e) {
 // -----------------------------------------------------------------------------
 // -----------------------------------------------------------------------------
 
+/**
+ * Register default block packages with this runtime.
+ * @todo Prefix opcodes with package name.
+ * @private
+ */
+Runtime.prototype._registerBlockPackages = function () {
+    for (var packageName in defaultBlockPackages) {
+        if (defaultBlockPackages.hasOwnProperty(packageName)) {
+            // @todo pass a different runtime depending on package privilege?
+            var packageObject = new (defaultBlockPackages[packageName])(this);
+            var packageContents = packageObject.getPrimitives();
+            for (var op in packageContents) {
+                if (packageContents.hasOwnProperty(op)) {
+                    this._primitives[op] =
+                        packageContents[op].bind(packageObject);
+                }
+            }
+        }
+    }
+};
+
+/**
+ * Retrieve the function associated with the given opcode.
+ * @param {!string} opcode The opcode to look up.
+ * @return {Function} The function which implements the opcode.
+ */
+Runtime.prototype.getOpcodeFunction = function (opcode) {
+    return this._primitives[opcode];
+};
+
+// -----------------------------------------------------------------------------
+// -----------------------------------------------------------------------------
+
 /**
  * Create a thread and push it to the list of threads.
  * @param {!string} id ID of block that starts the stack
@@ -306,4 +352,14 @@ Runtime.prototype._getSubstack = function (id) {
     return this.blocks[id].fields['SUBSTACK'];
 };
 
+/**
+ * Helper to get the opcode for a particular block
+ * @param {?string} id ID of block to query
+ * @return {?string} the opcode corresponding to that block
+ */
+Runtime.prototype._getOpcode = function (id) {
+    if (typeof this.blocks[id] === 'undefined') return null;
+    return this.blocks[id].opcode;
+};
+
 module.exports = Runtime;

src/engine/sequencer.js

@@ -58,10 +58,28 @@ Sequencer.prototype.stepThreads = function (threads) {
  * @param {!Thread} thread Thread object to step
  */
 Sequencer.prototype.stepThread = function (thread) {
-    // @todo Actually run the blocks
-    // Currently goes to the next block in the sequence.
-    var nextBlock = this.runtime._getNextBlock(thread.nextBlock);
-    thread.nextBlock = nextBlock;
+    var opcode = this.runtime._getOpcode(thread.nextBlock);
+
+    if (!opcode) {
+        console.warn('Could not get opcode for block: ' + thread.nextBlock);
+    }
+    else {
+        var blockFunction = this.runtime.getOpcodeFunction(opcode);
+        if (!blockFunction) {
+            console.warn('Could not get implementation for opcode: ' + opcode);
+        }
+        else {
+            try {
+                blockFunction();
+            }
+            catch(e) {
+                console.error('Exception calling block function',
+                    {opcode: opcode, exception: e});
+            }
+        }
+    }
+
+    thread.nextBlock = this.runtime._getNextBlock(thread.nextBlock);
 };
 
 module.exports = Sequencer;