https://github.com/rksm/estree-to-js

Parser / JSON + visitor generator of the markdown estree spec (https://github.com/estree/estree)
https://github.com/rksm/estree-to-js

Last synced: about 1 month ago
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Parser / JSON + visitor generator of the markdown estree spec (https://github.com/estree/estree)

• Host: GitHub
• URL: https://github.com/rksm/estree-to-js
• Owner: rksm
• License: mit
• Created: 2016-02-19T21:28:33.000Z (almost 9 years ago)
• Default Branch: master
• Last Pushed: 2024-10-11T14:07:15.000Z (3 months ago)
• Last Synced: 2024-10-13T10:25:22.810Z (3 months ago)
• Language: JavaScript
• Homepage:
• Size: 57.6 KB
• Stars: 0
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# estree-to-js

Parser / JSON + visitor generator of the markdown [estree spec](https://github.com/estree/estree);

# Usage

## npdejs API

### estree-to-js interface:

```js

var estree = require("estree-to-js");

var visitorSource = estree.fetch("es6")

  .then(estree.parse)

  .then(spec => estree.createVisitor(spec, []/*exceptions*/, "MyVisitor"))

  .catch(console.error)

```

### Visitors

Creation of visitor:

```js

var visitor;

visitorSource

  .then(source => eval(source + "\n" + "MyVisitor"))

  .then(MyVisitor => visitor = new MyVisitor());

```

#### Print path example

visitors have an `accept(node, state, path)` method and visitNodeType methods

like `visitVariableDeclaration(node, state, path)`. You can customize it to

your needs, for example:

```js

var lang = require("lively.lang"), ast = require("lively.ast");

visitor.accept = lang.fun.wrap(visitor.accept, (proceed, node, state, path) => {

  state.push(path.join(".") + " - " + node.type);

  proceed(node, state, path);

});

var state = [];

visitor.accept(ast.parse("var x = 1+3"), state, []);

console.log(state.join("\n")); // =>

                               //   - Program

                               //   body.0 - VariableDeclaration

                               //   body.0.declarations.0 - VariableDeclarator

                               //   ...

```

#### Rewriting example

```js

var replacer = (node) => lang.obj.merge(node, {id: {type: "Identifier", name: "foo_" + node.id.name}})

var visitor = new MyVisitor();

visitor.accept = lang.fun.wrap(visitor.accept, (proceed, node, state, path) => {

  if (node.type === "VariableDeclarator") node = replacer(node);

  return proceed(node, state, path);

});

var rewritten = visitor.accept(ast.parse("var x = 1 + 3"), null, []);

ast.stringify(rewritten); // => var foo_x = 1 + 3;

```

## command line

    --out			file output file to write

    --generate-json-spec	fetch and parse markdown source and generate JSON spec from it (default)

    --generate-visitor	generate source code for AST visitor class

    --json-spec		file to json spec. If specified it is used instead of fetching + parsing

### Examples:

- `./bin/estree-to-js.js es6` prints JSON spec of es6 estree

- `./bin/estree-to-js.js es6 --generate-visitor` prints JS source es6 estree visitor class

# License

[MIT](LICENSE)