mirror of
https://github.com/scratchfoundation/scratch-vm.git
synced 2024-12-23 22:42:27 -05:00
87 lines
2.4 KiB
Markdown
87 lines
2.4 KiB
Markdown
## scratch-vm
|
|
#### Scratch VM is a library for representing, running, and maintaining the state of computer programs written using [Scratch Blocks](https://github.com/LLK/scratch-blocks).
|
|
|
|
[](https://travis-ci.org/LLK/scratch-vm)
|
|
[](https://david-dm.org/LLK/scratch-vm)
|
|
[](https://david-dm.org/LLK/scratch-vm#info=devDependencies)
|
|
|
|
## Installation
|
|
```bash
|
|
npm install scratch-vm
|
|
```
|
|
|
|
## Setup
|
|
```js
|
|
var VirtualMachine = require('scratch-vm');
|
|
var vm = new VirtualMachine();
|
|
|
|
// Block events
|
|
workspace.addChangeListener(vm.blockListener);
|
|
var flyoutWorkspace = workspace.toolbox_.flyout_.workspace_;
|
|
flyoutWorkspace.addChangeListener(vm.flyoutBlockListener);
|
|
|
|
// 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
|
|
{
|
|
"7AJZR#NA;m*b}R]pdq63": {
|
|
"id": "7AJZR#NA;m*b}R]pdq63",
|
|
"opcode": "control_wait",
|
|
"inputs": {
|
|
"DURATION": {
|
|
"name": "DURATION",
|
|
"block": ",xA8/S!Z6+kR,9dph.rO"
|
|
}
|
|
},
|
|
"fields": {},
|
|
"next": null,
|
|
"topLevel": true
|
|
},
|
|
",xA8/S!Z6+kR,9dph.rO": {
|
|
"id": ",xA8/S!Z6+kR,9dph.rO",
|
|
"opcode": "math_number",
|
|
"inputs": {},
|
|
"fields": {
|
|
"NUM": {
|
|
"name": "NUM",
|
|
"value": "1"
|
|
}
|
|
},
|
|
"next": null,
|
|
"topLevel": false
|
|
}
|
|
}
|
|
```
|
|
|
|
## Testing
|
|
```bash
|
|
make test
|
|
```
|
|
|
|
```bash
|
|
make coverage
|
|
```
|
|
|
|
## Donate
|
|
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, design, community, and resource development efforts. Donations of any size are appreciated. Thank you!
|