Virtual Machine for Clip CC
#### ClipCC VM is a library for representing, running, and maintaining the state of computer programs written using ClipCC Blocks.
To install as a dependency for your own application:
``bash`
yarn install clipcc-vm`
To set up a development environment to edit clipcc-vm yourself:bash`
git clone https://github.com/LLK/clipcc-vm.git
cd clipcc-vm
yarn install
For convenience, we've included a development server with the VM. This is sometimes useful when running in an environment that's loading remote resources (e.g., SVGs from the Scratch server). If you would like to use your modified VM with the full Scratch 3.0 GUI, follow the instructions to link the VM to the GUI.
bash
yarn start
`Playground
To view the Playground, make sure the dev server's running and go to http://localhost:8073/playground/ - you will be directed to the playground, which demonstrates various tools and internal state.
Standalone Build
`bash
yarn run build
``html
`How to include in a Node.js App
For an extended setup example, check out the /src/playground directory, which includes a fully running VM instance.
`js
var VirtualMachine = require('clipcc-vm');
var vm = new VirtualMachine({appVersion: '0.0.0'});// Block events
Scratch.workspace.addChangeListener(vm.blockListener);
// Run threads
vm.start();
`Abstract Syntax Tree
#### Overview
The Virtual Machine constructs and maintains the state of an Abstract Syntax Tree (AST) by listening to events emitted by the scratch-blocks workspace via the
blockListener. Each target (code-running object, for example, a sprite) keeps an AST for its blocks. At any time, the current state of an AST can be viewed by inspecting the vm.runtime.targets[...].blocks object.#### Anatomy of a Block
The VM's block representation contains all the important information for execution and storage. Here's an example representing the "when key pressed" script on a workspace:
`json
{
"_blocks": {
"Q]PK~yJ@BTV8Y~FfISeo": {
"id": "Q]PK~yJ@BTV8Y~FfISeo",
"opcode": "event_whenkeypressed",
"inputs": {
},
"fields": {
"KEY_OPTION": {
"name": "KEY_OPTION",
"value": "space"
}
},
"next": null,
"topLevel": true,
"parent": null,
"shadow": false,
"x": -69.333333333333,
"y": 174
}
},
"_scripts": [
"Q]PK~yJ@BTV8Y~FfISeo"
]
}
`Testing
`bash
yarn test
``bash
yarn run coverage
`Publishing to GitHub Pages
`bash
yarn run deploy
`This will push the currently built playground to the gh-pages branch of the
currently tracked remote. If you would like to change where to push to, add
a repo url argument:
`bash
yarn run deploy -- -r
``