mirror of
https://github.com/scratchfoundation/scratch-vm.git
synced 2024-12-22 22:12:28 -05:00
93 lines
2.5 KiB
Markdown
93 lines
2.5 KiB
Markdown
## scratch-vm
|
|
|
|
[](https://travis-ci.com/LLK/scratch-vm)
|
|
|
|
## Installation
|
|
```bash
|
|
npm install scratch-vm
|
|
```
|
|
|
|
## Setup
|
|
```js
|
|
var VirtualMachine = require('scratch-vm');
|
|
var vm = new VirtualMachine();
|
|
|
|
// Block events
|
|
workspace.addChangeListener(function(e) {
|
|
// Handle "tapping" a block
|
|
if (e instanceof Blockly.Events.Ui && e.element === 'click') {
|
|
var stackBlock = workspace.getBlockById(e.blockId).getRootBlock().id;
|
|
vm.runtime.toggleStack(stackBlock);
|
|
// Otherwise, pass along to the block listener
|
|
} else {
|
|
vm.blockListener(e);
|
|
}
|
|
});
|
|
|
|
// Run threads
|
|
vm.runtime.start();
|
|
```
|
|
|
|
## Standalone Build
|
|
```bash
|
|
make build
|
|
```
|
|
|
|
```html
|
|
<script src="/path/to/vm.js"></script>
|
|
<script>
|
|
var vm = new window.VirtualMachine();
|
|
// do things
|
|
</script>
|
|
```
|
|
|
|
## Abstract Syntax Tree
|
|
|
|
#### Overview
|
|
The Virtual Machine constructs and maintains the state of an [Abstract Syntax Tree](https://en.wikipedia.org/wiki/Abstract_syntax_tree) (AST) by listening to events emitted by the [scratch-blocks](https://github.com/LLK/scratch-blocks) workspace via the `blockListener`. At any time, the current state of the AST can be viewed by inspecting the `vm.runtime.blocks` object.
|
|
|
|
#### Anatomy of a Block
|
|
```json
|
|
{
|
|
"id": "^1r~63Gdl7;Dh?I*OP3_",
|
|
"opcode": "wedo_motorclockwise",
|
|
"next": null,
|
|
"fields": {
|
|
"DURATION": {
|
|
"name": "DURATION",
|
|
"value": null,
|
|
"blocks": {
|
|
"1?P=eV(OiDY3vMk!24Ip": {
|
|
"id": "1?P=eV(OiDY3vMk!24Ip",
|
|
"opcode": "math_number",
|
|
"next": null,
|
|
"fields": {
|
|
"NUM": {
|
|
"name": "NUM",
|
|
"value": "10",
|
|
"blocks": null
|
|
}
|
|
}
|
|
}
|
|
}
|
|
},
|
|
"SUBSTACK": {
|
|
"name": "SUBSTACK",
|
|
"value": "@1ln(HsUO4!]*2*%BrE|",
|
|
"blocks": null
|
|
}
|
|
}
|
|
}
|
|
```
|
|
|
|
## Testing
|
|
```bash
|
|
make test
|
|
```
|
|
|
|
```bash
|
|
make coverage
|
|
```
|
|
|
|
## Donation
|
|
We provide [Scratch](https://scratch.mit.edu) free of charge, and want to keep it that way! Please consider making a [donation](https://secure.donationpay.org/scratchfoundation/) to support our continued engineering, community, and resource development efforts. Donations of any size are appreciated. Thank you!
|