'event_whenstopclicked',
    'sensing_openurl'

This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.

This program is based on [scratchfoundation/scratch-vm](https://github.com/scratchfoundation/scratch-vm), which is under this license:

```
Copyright (c) 2016, Massachusetts Institute of Technology
All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
```

        // Block ID
        case 'motion_changexyby':
            return {
                // "kind" is code generator ID.
                kind: 'motion.changeXY',
                dx: this.descendInputOfBlock(block, 'DX'), // Added X input.
                dy: this.descendInputOfBlock(block, 'DY') // Added Y input.
            };

        // Check for this block's code generator ID.
        case 'motion.changeXY':
            // Add code to generated JavaScript.
            this.source += `target.setXY(target.x + ${this.descendInput(node.dx).asNumber() /* Insert added X input. */ }, target.y + ${this.descendInput(node.dy).asNumber() /* Insert added Y input. */ });\n`;
            break;

    /**
     * Start all threads that start with the green flag.
     */
    greenFlag () {
        // Emit stop event to allow blocks to clean up any state.
        this.emit(Runtime.PROJECT_STOP_ALL);
        // Dispose all clones.
        const newTargets = [];
        for (let i = 0; i < this.targets.length; i++) {
            this.targets[i].onStopAll();
            if (Object.prototype.hasOwnProperty.call(this.targets[i], 'isOriginal') &&
                !this.targets[i].isOriginal) {
                this.targets[i].dispose();
            } else {
                newTargets.push(this.targets[i]);
            }
        }
        this.targets = newTargets;
        // Dispose of the active thread.
        if (this.sequencer.activeThread !== null) {
            this._stopThread(this.sequencer.activeThread);
        }
        // Remove all remaining threads from executing in the next tick.
        this.threads = [];
        this.threadMap.clear();
        this.resetRunId();
        this.emit(Runtime.PROJECT_START);
        this.updateCurrentMSecs();
        this.ioDevices.clock.resetProjectTimer();
        this.targets.forEach(target => target.clearEdgeActivatedValues());
        // Inform all targets of the green flag.
        for (let i = 0; i < this.targets.length; i++) {
            this.targets[i].onGreenFlag();
        }
        this.startHats('event_whenflagclicked');
    }
    /**
     * Stop "everything."
     */
    stopAll () {
    
        // Emit stop event to allow blocks to clean up any state.
        this.emit(Runtime.PROJECT_STOP_ALL);
        // Dispose all clones.
        const newTargets = [];
        for (let i = 0; i < this.targets.length; i++) {
            this.targets[i].onStopAll();
            if (Object.prototype.hasOwnProperty.call(this.targets[i], 'isOriginal') &&
                !this.targets[i].isOriginal) {
                this.targets[i].dispose();
            } else {
                newTargets.push(this.targets[i]);
            }
        }
        this.targets = newTargets;
        // Dispose of the active thread.
        if (this.sequencer.activeThread !== null) {
            this._stopThread(this.sequencer.activeThread);
        }
        this.startHats('event_whenstopclicked');
    }

// irgen
        case 'control_all_at_once':
            // In Scratch 3, this block behaves like "if 1 = 1"
            return {
                kind: 'control.allAtOnce',
                condition: {
                    kind: 'constant',
                    value: true
                },
                whenTrue: this.descendSubstack(block, 'SUBSTACK'),
                whenFalse: []
            };
// jsgen
        case 'control.allAtOnce':
            this.isWarp = false;
            this.descendStack(node.do, new Frame(false));
            this.isWarp = true;
            break;