WIP

.eslintrc

@@ -0,0 +1,17 @@
+{
+    "rules": {
+        "curly": [2, "multi-line"],
+        "eol-last": [2],
+        "indent": [2, 4],
+        "quotes": [2, "single"],
+        "linebreak-style": [2, "unix"],
+        "max-len": [2, 80, 4],
+        "semi": [2, "always"],
+        "strict": [2, "never"]
+    },
+    "env": {
+        "node": true,
+        "browser": true
+    },
+    "extends": "eslint:recommended"
+}

.npmrc

@@ -1,5 +0,0 @@
-engine-strict=true
-save-exact=true
-save-prefix=~
-init-license=BSD-3-Clause
-init-author-name=Massachusetts Institute of Technology

Makefile

@@ -1,12 +1,21 @@
 ESLINT=./node_modules/.bin/eslint
 NODE=node
 TAP=./node_modules/.bin/tap
+WEBPACK=./node_modules/.bin/webpack --progress --colors
+
+# ------------------------------------------------------------------------------
+
+build:
+	$(WEBPACK)
+
+watch:
+	$(WEBPACK) --watch
 
 # ------------------------------------------------------------------------------
 
 lint:
-	$(ESLINT) ./*.js
-	$(ESLINT) ./lib/*.js
+	$(ESLINT) ./src/*.js
+	$(ESLINT) ./src/**/*.js
 	$(ESLINT) ./test/**/*.js
 
 test:
@@ -21,4 +30,4 @@ benchmark:
 
 # ------------------------------------------------------------------------------
 
-.PHONY: lint test coverage benchmark
+.PHONY: build lint test coverage benchmark

README.md

@@ -5,9 +5,29 @@
 npm install scratch-vm
 ```
 
-## Integration
+## Setup
 ```js
+var VirtualMachine = require('scratch-vm');
+var vm = new VirtualMachine();
 
+// Block events
+
+// UI events
+
+// Listen for events
+```
+
+## Standalone Build
+```bash
+make build
+```
+
+```html
+<script src="/path/to/vm.js"></script>
+<script>
+    var vm = new window.VirtualMachine();
+    // do things
+</script>
 ```
 
 ## Testing

package.json

@@ -1,7 +1,7 @@
 {
   "name": "scratch-vm",
   "version": "1.0.0",
-  "description": "",
+  "description": "Virtual Machine for Scratch 3.0",
   "author": "Massachusetts Institute of Technology",
   "license": "BSD-3-Clause",
   "homepage": "https://github.com/LLK/scratch-vm#readme",
@@ -9,13 +9,15 @@
     "type": "git",
     "url": "git+ssh://git@github.com/LLK/scratch-vm.git"
   },
-  "main": "index.js",
+  "main": "./src/index.js",
   "scripts": {
     "test": "make test"
   },
+  "dependencies": {},
   "devDependencies": {
     "benchmark": "2.1.0",
     "eslint": "2.7.0",
-    "tap": "5.7.1"
+    "tap": "5.7.1",
+    "webpack": "1.13.0"
   }
 }

src/engine/primatives.js

@@ -0,0 +1,41 @@
+function Primitives () {
+
+}
+
+Primitives.prototype.event_whenflagclicked = function (thread, runtime) {
+    // No-op: flags are started by the interpreter but don't do any action
+    // Take 1/3 second to show running state
+    if (Date.now() - thread.blockFirstTime < 300) {
+        thread.yield = true;
+        return;
+    }
+};
+
+Primitives.prototype.control_repeat = function (thread, runtime) {
+    // Take 1/3 second to show running state
+    if (Date.now() - thread.blockFirstTime < 300) {
+        thread.yield = true;
+        return;
+    }
+    if (thread.repeatCounter == -1) {
+        thread.repeatCounter = 10; // @todo from the arg
+    }
+    if (thread.repeatCounter > 0) {
+        thread.repeatCounter -= 1;
+        runtime.interpreter.startSubstack(thread);
+    } else {
+        thread.repeatCounter = -1;
+        thread.nextBlock = runtime.getNextBlock(thread.blockPointer);
+    }
+};
+
+Primitives.prototype.control_forever = function (thread, runtime) {
+    // Take 1/3 second to show running state
+    if (Date.now() - thread.blockFirstTime < 300) {
+        thread.yield = true;
+        return;
+    }
+    runtime.interpreter.startSubstack(thread);
+};
+
+module.exports = Primitives;

src/engine/runtime.js

@@ -0,0 +1,119 @@
+var Primitives = require('./primatives');
+var Sequencer = require('./sequencer');
+var Thread = require('./thread');
+
+var STEP_THREADS_INTERVAL = 1000 / 30;
+
+/**
+ * A simple runtime for blocks.
+ */
+function Runtime () {
+    this.sequencer = new Sequencer(this);
+    this.primitives = new Primitives();
+
+    // State
+    this.blocks = {};
+    this.stacks = [];
+}
+
+Runtime.prototype.createBlock = function (e) {
+    // Create new block
+    this.blocks[e.id] = {
+        id: e.id,
+        opcode: e.opcode,
+        next: null,
+        inputs: {}
+    };
+
+    // Push block id to stacks array. New blocks are always a stack even if only
+    // momentary. If the new block is added to an existing stack this stack will
+    // be removed by the `moveBlock` method below.
+    this.stacks.push(e.id);
+};
+
+Runtime.prototype.moveBlock = function (e) {
+    var _this = this;
+
+    // Block has a new parent
+    if (e.oldParent === undefined && e.newParent !== undefined) {
+        // Remove stack
+        _this._deleteStack(e.id);
+
+        // Update new parent
+        if (e.newInput === undefined) {
+            _this.blocks[e.newParent].next = e.id;
+        } else {
+            _this.blocks[e.newParent].inputs[e.newInput] = e.id;
+        }
+    }
+
+    // Block was removed from parent
+    if (e.newParentId === undefined && e.oldParent !== undefined) {
+        // Add stack
+        _this.stacks.push(e.id);
+
+        // Update old parent
+        if (e.oldInput === undefined) {
+            _this.blocks[e.oldParent].next = null;
+        } else {
+            delete _this.blocks[e.oldParent].inputs[e.oldInput];
+        }
+    }
+};
+
+Runtime.prototype.changeBlock = function (e) {
+    // @todo
+};
+
+Runtime.prototype.deleteBlock = function (e) {
+    // @todo Stop threads running on this stack
+
+    // Delete children
+    var block = this.blocks[e.id];
+    if (block.next !== null) {
+        this.deleteBlock({id: block.next});
+    }
+
+    // Delete inputs
+    for (var i in block.inputs) {
+        this.deleteBlock({id: block.inputs[i]});
+    }
+
+    // Delete stack
+    this._deleteStack(e.id);
+
+    // Delete block
+    delete this.blocks[e.id];
+};
+
+Runtime.prototype.runAllStacks = function () {
+    // @todo
+};
+
+Runtime.prototype.runStack = function () {
+    // @todo
+};
+
+Runtime.prototype.stopAllStacks = function () {
+    // @todo
+};
+
+// -----------------------------------------------------------------------------
+// -----------------------------------------------------------------------------
+
+Runtime.prototype._deleteStack = function (id) {
+    var i = this.stacks.indexOf(id);
+    if (i > -1) this.stacks.splice(i, 1);
+};
+
+Runtime.prototype._getNextBlock = function (id) {
+    if (typeof this.blocks[id] === 'undefined') return null;
+    return this.blocks[id].next;
+};
+
+Runtime.prototype._getSubstack = function (id) {
+    if (typeof this.blocks[id] === 'undefined') return null;
+    return this.blocks[id].inputs['SUBSTACK'];
+};
+
+module.exports = Runtime;

src/engine/sequencer.js

@@ -0,0 +1,29 @@
+var Timer = require('../util/timer');
+
+/**
+ * Constructor
+ */
+function Sequencer (runtime) {
+    // Bi-directional binding for runtime
+    this.runtime = runtime;
+
+    // State
+    this.runningThreads = [];
+    this.workTime = 30;
+    this.timer = new Timer();
+    this.currentTime = 0;
+}
+
+Sequencer.prototype.stepAllThreads = function () {
+
+};
+
+Sequencer.prototype.stepThread = function (thread) {
+
+};
+
+Sequencer.prototype.startSubstack = function (thread) {
+
+};
+
+module.exports = Sequencer;

src/engine/thread.js

@@ -0,0 +1,19 @@
+/**
+ * Thread is an internal data structure used by the interpreter. It holds the
+ * state of a thread so it can continue from where it left off, and it has
+ * a stack to support nested control structures and procedure calls.
+ *
+ * @param {String} Unique block identifier
+ */
+function Thread (id) {
+    this.topBlockId = id;
+    this.blockPointer = id;
+    this.blockFirstTime = -1;
+    this.nextBlock = null;
+    this.waiting = null;
+    this.runningDeviceBlock = false;
+    this.stack = [];
+    this.repeatCounter = -1;
+}
+
+module.exports = Thread;

src/index.js

@@ -0,0 +1,148 @@
+var EventEmitter = require('events');
+var util = require('util');
+
+var Runtime = require('./engine/runtime');
+
+/**
+ * Handles connections between blocks, stage, and extensions.
+ *
+ * @author Andrew Sliwinski <ascii@media.mit.edu>
+ */
+function VirtualMachine () {
+    var instance = this;
+
+    // Bind event emitter and runtime to VM instance
+    EventEmitter.call(instance);
+    instance.runtime = new Runtime();
+
+    /**
+     * Event listener for blockly. Handles validation and serves as a generic
+     * adapter between the blocks and the runtime interface.
+     *
+     * @param {Object} Blockly "block" event
+     */
+    instance.blockListener = function (e) {
+        // Validate event
+        if (typeof e !== 'object') return;
+        if (typeof e.blockId !== 'string') return;
+
+        // Blocks
+        switch (e.type) {
+        case 'create':
+            instance.runtime.createBlock({
+                id: e.blockId,
+                opcode: e.xml.attributes.type.value
+            });
+            break;
+        case 'move':
+            instance.runtime.moveBlock({
+                id: e.blockId,
+                oldParent: e.oldParentId,
+                oldInput: e.oldInputName,
+                newParent: e.newParentId,
+                newInput: e.newInputName
+            });
+            break;
+        case 'change':
+            instance.runtime.changeBlock({
+                id: e.blockId
+            });
+            break;
+        case 'delete':
+            instance.runtime.deleteBlock({
+                id: e.blockId
+            });
+            break;
+        }
+    };
+
+    // @todo UI listener
+
+    // @todo Forward runtime events
+
+    // Event dispatcher
+    // this.types = keymirror({
+    //     // Messages to runtime
+    //     CREATE_BLOCK: null,
+    //     MOVE_BLOCK: null,
+    //     CHANGE_BLOCK: null,
+    //     DELETE_BLOCK: null,
+    //
+    //     ADD_DEVICE: null,
+    //     REMOVE_DEVICE: null,
+    //
+    //     RUN_STRIP: null,
+    //     RUN_ALL_STRIPS: null,
+    //     STOP_ALL_STRIPS: null,
+    //     RUN_PALETTE_BLOCK: null,
+    //
+    //     // Messages from runtime - subscribe to these
+    //     FEEDBACK_EXECUTING_BLOCK: null,
+    //     FEEDBACK_STOPPED_EXECUTING_BLOCK: null,
+    //     DEVICE_RUN_OP: null,
+    //     DEVICE_STOP_OP: null,
+    //
+    //     // Tell back the interpreter device has finished an op
+    //     DEVICE_FINISHED_OP: null
+    // });
+
+    // Bind block event stream
+    // setTimeout(function () {
+    //     _this.emit('foo', 'bar');
+    // }, 1000);
+}
+
+/**
+ * Inherit from EventEmitter
+ */
+util.inherits(VirtualMachine, EventEmitter);
+
+// VirtualMachine.prototype.changeListener = function (e) {
+//     var _this = this;
+//     console.dir(this);
+//
+//     switch (e.type) {
+//     case 'create':
+//         console.dir(e);
+//         _this.runtime.createBlock(
+//             e.blockId,
+//             event.xml.attributes.type.value
+//         );
+//         break;
+//     case 'change':
+//         // @todo
+//         break;
+//     case 'move':
+//         // @todo
+//         break;
+//     case 'delete':
+//         // @todo
+//         break;
+//     }
+// };
+//
+// VirtualMachine.prototype.tapListener = function (e) {
+//     // @todo
+// };
+
+VirtualMachine.prototype.start = function () {
+    this.runtime.runAllGreenFlags();
+};
+
+VirtualMachine.prototype.stop = function () {
+    this.runtime.stop();
+};
+
+VirtualMachine.prototype.save = function () {
+    // @todo Serialize runtime state
+};
+
+VirtualMachine.prototype.load = function () {
+    // @todo Deserialize and apply runtime state
+};
+
+/**
+ * Export and bind to `window`
+ */
+module.exports = VirtualMachine;
+if (typeof window !== 'undefined') window.VirtualMachine = module.exports;

src/util/timer.js

@@ -0,0 +1,21 @@
+/**
+ * Constructor
+ * @todo Swap out Date.now() with microtime module that works in node & browsers
+ */
+function Timer () {
+    this.startTime = 0;
+}
+
+Timer.prototype.time = function () {
+    return Date.now();
+};
+
+Timer.prototype.start = function () {
+    this.startTime = this.time();
+};
+
+Timer.prototype.stop = function () {
+    return this.startTime - this.time();
+};
+
+module.exports = Timer;

test/fixtures/blocks.js

@@ -0,0 +1,26 @@
+var events = require('events');
+var util = require('util');
+
+/**
+ * Simulates event emitter / listener patterns from Scratch Blocks.
+ *
+ * @author Andrew Sliwinski <ascii@media.mit.edu>
+ */
+function Blocks () {
+
+}
+
+/**
+ * Inherit from EventEmitter to enable messaging.
+ */
+util.inherits(VirtualMachine, events.EventEmitter);
+
+Blocks.prototype.spaghetti = function () {
+    this.emit('');
+};
+
+Blocks.prototype.spam = function () {
+    this.emit('');
+};
+
+module.exports = Blocks;

test/unit/runtime.js

@@ -0,0 +1,81 @@
+var test = require('tap').test;
+var Runtime = require('../../src/engine/runtime');
+
+test('spec', function (t) {
+    var r = new Runtime();
+
+    t.type(Runtime, 'function');
+    t.type(r, 'object');
+    t.ok(r instanceof Runtime);
+
+    t.type(r.blocks, 'object');
+    t.type(r.stacks, 'object');
+    t.ok(Array.isArray(r.stacks));
+
+    t.type(r.createBlock, 'function');
+    t.type(r.moveBlock, 'function');
+    t.type(r.changeBlock, 'function');
+    t.type(r.deleteBlock, 'function');
+
+    t.end();
+});
+
+test('create', function (t) {
+    var r = new Runtime();
+    r.createBlock({
+        id: 'foo',
+        opcode: 'TEST_BLOCK'
+    });
+
+    t.type(r.blocks['foo'], 'object');
+    t.equal(r.blocks['foo'].opcode, 'TEST_BLOCK');
+    t.notEqual(r.stacks.indexOf('foo'), -1);
+    t.end();
+});
+
+test('move', function (t) {
+    var r = new Runtime();
+    r.createBlock({
+        id: 'foo',
+        opcode: 'TEST_BLOCK'
+    });
+    r.createBlock({
+        id: 'bar',
+        opcode: 'TEST_BLOCK'
+    });
+
+    // Attach 'bar' to the end of 'foo'
+    r.moveBlock({
+        id: 'bar',
+        newParent: 'foo'
+    });
+    t.equal(r.stacks.length, 1);
+    t.equal(Object.keys(r.blocks).length, 2);
+    t.equal(r.blocks['foo'].next, 'bar');
+
+    // Detach 'bar' from 'foo'
+    r.moveBlock({
+        id: 'bar',
+        oldParent: 'foo'
+    });
+    t.equal(r.stacks.length, 2);
+    t.equal(Object.keys(r.blocks).length, 2);
+    t.equal(r.blocks['foo'].next, null);
+
+    t.end();
+});
+
+test('delete', function (t) {
+    var r = new Runtime();
+    r.createBlock({
+        id: 'foo',
+        opcode: 'TEST_BLOCK'
+    });
+    r.deleteBlock({
+        id: 'foo'
+    });
+
+    t.type(r.blocks['foo'], 'undefined');
+    t.equal(r.stacks.indexOf('foo'), -1);
+    t.end();
+});

test/unit/spec.js

@@ -1,6 +1,18 @@
 var test = require('tap').test;
-var vm = require('../../index');
+var VirtualMachine = require('../../src/index');
 
 test('spec', function (t) {
+    var vm = new VirtualMachine('foo');
+
+    t.type(VirtualMachine, 'function');
+    t.type(vm, 'object');
+
+    t.type(vm.blockListener, 'function');
+    // t.type(vm.uiListener, 'function');
+    // t.type(vm.start, 'function');
+    // t.type(vm.stop, 'function');
+    // t.type(vm.save, 'function');
+    // t.type(vm.load, 'function');
+
     t.end();
 });

test/unit/thread.js

@@ -0,0 +1,10 @@
+var test = require('tap').test;
+var Thread = require('../../src/engine/thread');
+
+test('spec', function (t) {
+    var thread = new Thread('foo');
+
+    t.type(Thread, 'function');
+    t.type(thread, 'object');
+    t.end();
+});

test/unit/timer.js

@@ -0,0 +1,41 @@
+var test = require('tap').test;
+var Timer = require('../../src/util/timer');
+
+test('spec', function (t) {
+    var timer = new Timer();
+
+    t.type(Timer, 'function');
+    t.type(timer, 'object');
+
+    t.type(timer.startTime, 'number');
+    t.type(timer.time, 'function');
+    t.type(timer.start, 'function');
+    t.type(timer.stop, 'function');
+
+    t.end();
+});
+
+test('time', function (t) {
+    var timer = new Timer();
+    var time = timer.time();
+
+    t.ok(Date.now() >= time);
+    t.end();
+});
+
+test('start / stop', function (t) {
+    var timer = new Timer();
+    var start = timer.time();
+    var delay = 100;
+    var threshold = 1000 / 60;  // 60 hz
+
+    // Start timer
+    timer.start();
+
+    // Wait and stop timer
+    setTimeout(function () {
+        var stop = timer.stop();
+        t.ok(stop >= -(delay + threshold) && stop <= -(delay - threshold));
+        t.end();
+    }, delay);
+});

webpack.config.js

@@ -0,0 +1,18 @@
+var webpack = require('webpack');
+
+module.exports = {
+    entry: {
+        'vm': './src/index.js',
+        'vm.min': './src/index.js'
+    },
+    output: {
+        path: __dirname,
+        filename: '[name].js'
+    },
+    plugins: [
+        new webpack.optimize.UglifyJsPlugin({
+            include: /\.min\.js$/,
+            minimize: true
+        })
+    ]
+};