https://github.com/tgrospic/pegjs-livescript-plugin
PEG.js LiveScript plugin
https://github.com/tgrospic/pegjs-livescript-plugin
language-plugin livescript pegjs syntax-highlighting
Last synced: 3 months ago
JSON representation
PEG.js LiveScript plugin
- Host: GitHub
- URL: https://github.com/tgrospic/pegjs-livescript-plugin
- Owner: tgrospic
- License: mit
- Created: 2015-09-03T15:55:31.000Z (over 9 years ago)
- Default Branch: master
- Last Pushed: 2017-04-15T17:22:22.000Z (about 8 years ago)
- Last Synced: 2025-02-04T04:52:45.308Z (4 months ago)
- Topics: language-plugin, livescript, pegjs, syntax-highlighting
- Language: LiveScript
- Size: 7.81 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# PEG.js LiveScript plugin
[![build status][travis-image]][travis-url]
[![npm version][version-image]][version-url]
[PEG.js][peg-js] is a great tool for generating parsers in JavaScript with very concise grammar.
For more in-depth entertainment on packrat parsers and PEGs;
here is the wild stuff [Packrat Parsing and Parsing Expression Grammars][peg-bford].
[LiveScript][livescript] is a glorious language which compiles to JavaScript.
The _everything-is-expression_ style and its sugary syntax makes me a smile every time. :smile:
This plugin, following the example of the existing CoffeeScript plugins
[[Dignifiedquire/pegjs-coffee-plugin][cp1], [ttilley/pegcoffee][cp2]],
allows writing PEG.js grammar with
[LiveScript][livescript] code in _initializer_, _actions_ and _predicates_.
_There is a little difference in comparison with Coffee plugins.
Context `this` or `@` remains unchanged._
## Installation
```sh
$ npm install pegjs-livescript-plugin
```
## Usage
#### Node.js
```ls
require! { PEG, 'pegjs-livescript-plugin' }
grammar = "Start = cs:.* { cs.join '' }"
# Build parser with LiveScript plugin
parser = PEG.buildParser grammar, plugins: [pegjs-livescript-plugin]
parser.parse 'PEG is fun!'
```
#### CLI
```sh
$ pegjs --plugin pegjs-livescript-plugin my-grammar.pegls
```
#### PEG.js LiveScript
```ls
# .pegls - PEG.js LiveScript grammar
{
my-var = 42
join-chars = (chars) ->
chars.join ''
}
Start
= cs:.* {
# my-var := 4711 # SyntaxError: assignment to undeclared "myVar"
my-var = 4711 # initializer variable `my-var == 42` is shadowed
join-chars cs
}
```
compiles to JavaScript
```js
{
var myVar, joinChars;
myVar = 42;
joinChars = function(chars){
return myVar + chars.join(''); // myVar === 42
};
}
Start
= ch:.* {
var myVar;
return myVar = 4711, joinChars(cs);
}
```
__Note__: variables defined in one scope (between `{` `}`) can not be modified in a different scope
not even with `:=`. Each scope is compiled separately which causes re-declaration of variables.
It seems to me that this is actually a _smart_ restriction (consequence) but I'm open to suggestions.
## Tests
```sh
$ npm test
```
## Todo
- browser build/test
- better compile/runtime error report (sourcemap?!)
- accept compiler options (eg. `const: true`)
## License
[The MIT License (MIT)][license]
[peg-js]: https://github.com/pegjs/pegjs
[peg-bford]: http://bford.info/packrat
[livescript]: https://github.com/gkz/LiveScript
[cp1]: https://github.com/Dignifiedquire/pegjs-coffee-plugin
[cp2]: https://github.com/ttilley/pegcoffee
[travis-image]: https://api.travis-ci.org/tgrospic/pegjs-livescript-plugin.svg
[travis-url]: https://travis-ci.org/tgrospic/pegjs-livescript-plugin
[version-image]: https://img.shields.io/npm/v/pegjs-livescript-plugin.svg
[version-url]: https://www.npmjs.com/package/pegjs-livescript-plugin
[license]: https://github.com/tgrospic/pegjs-livescript-plugin/blob/master/LICENSE