https://github.com/bates64/nearley-moo

ultra-fast tokenizer plugin for nearley :cow2:
https://github.com/bates64/nearley-moo

Last synced: about 1 month ago
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ultra-fast tokenizer plugin for nearley :cow2:

• Host: GitHub
• URL: https://github.com/bates64/nearley-moo
• Owner: bates64
• Created: 2017-03-19T19:41:45.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2017-07-11T15:17:45.000Z (over 7 years ago)
• Last Synced: 2024-11-28T18:11:51.387Z (about 1 month ago)
• Language: JavaScript
• Homepage:
• Size: 2.93 KB
• Stars: 4
• Watchers: 1
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md

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README

        
## nearley-moo

#### [moo (ultra-fast tokenizer)](https://github.com/tjvr/moo) plugin for [nearley](https://github.com/Hardmath123/nearley) :cow2:

[![npm](https://img.shields.io/npm/v/nearley-moo.svg)](https://npmjs.com/package/nearley-moo)

## install

**with npm**

```sh

npm install nearley-moo --save

```

**with yarn**

```sh

yarn add nearley-moo

```

## usage

**index.js**

```js

const moo = require('moo')

const nearley = require('nearley')

const grammar = require('./grammar.js') // compiled from grammar.ne

const tokens = require('./tokens.js')

const nm = require('nearley-moo').parser(nearley, grammar) // curried

let parser = nm(moo.compile(tokens))

// ignored tokens will not be passed to nearley

// helpful for whitespace and/or comments

parser.ignore('whitespace') // may be Array or String

// feed your lexer+parser combo as normal

parser.feed('if true then moomoomoo else cows')

console.log(parser.results) // just like nearley

```

**tokens.js**

```js

module.exports = {

  whitespace: /[ \t]+/,

  moo: /(moo)+/,

  cows: /cows/,

  boolean: [ 'true', 'false' ],

  keyword: [ 'if', 'then', 'else'],

}

```

**grammar.ne**

```ne

@{%

const nm = require('nearley-moo')

const tokens = require('./tokens.js')

nm(tokens)

%}

main -> %keyword_if expression %keyword_then expression %keyword_else expression

expression -> boolean

            | %moo

            | %cows

boolean -> %boolean_true  {% d => true %}

         | %boolean_false {% d => false %}

```