PEGjs Coffee Plugin 

Plugin for PEG.js to use CoffeeScript in actions. Because all I want
for christmas is CoffeeScript.

Status

The basic functionality is finished. Please test it and add feature
requests and issues here.

Requirements

* PEG.js (who would have guessed that?)
* CoffeeScript

Installation

#### Node.js

``bash
$ npm install pegjs-coffee-plugin
`
Then in your code call
`coffee-script
PEG = require 'pegjs'
coffee = require 'pegjs-coffee-plugin'

`

#### Browser

Download the
development
or the
minified version.
Now include all needed scripts in your html file like this.
`html


`

Usage

$3

After you have loaded all scripts you can do

`coffee-script
grammar = '' # Define your grammar
parser = PEG.buildParser grammar, plugins: [coffee]
`

$3


Just pass the pegjs commandline like this
`bash
$ pegjs --plugin pegjs-coffee-plugin myGrammar.pegcoffee myCompiledGrammar.js
`

Added Features

You now have a save scope shared between all actions and predicates.
To begin it is empty, then all declarations from the initializer are
added. Afterwards you can add and remove stuff as much as you like.
This scope is there even if you don't use the initializer. So you can
do something like the following.
`coffee-script
start = a { @result }
a = "a" { @result = "awesome" }
`
And this will correctly return "awesome" if you call parse("a").

Also all variable assignments in an action are safely scoped to the
action. { result = "awesome" } becomes { var result; result =
"awesome" }. This gives you the ability to explicitly share variables
with other actions via this and the security to just assign
variables for local use like you are used to when writing CoffeeScript.




Syntax changes


There is no need to call return anymore. You can just do
`coffee-script
start = a:"a" { "Great Stuff" }
`
which is the equivalent of

`javascript
start = a:"a" { return "Great Stuff"; }
`

If you declare variables in your initializer you set them on this.
`coffee-script
{
@result = ""
}
start
= awesome / rule { @result }
awesome
= "awesome" { @result = "awesome" }
rule
= "rule" { @result = "rule }
`


-------------

Development




$3

* Node.js with npm
* mocha
* expect.js
* http-server
* JSHint
* UglifyJS

$3

Clone the repo and run the install
`bash
$ git clone https://github.com/dignifiedquire/pegjs-coffee-plugin.git
$ cd pegjs-cofee-plugin
$ npm install && npm install pegjs
`

$3

`bash
$ make build
`

Running the tests

For the Node.js tests run
`bash
$ make test
`
and for the browser tests
`bash
$ make test-browser
``
and open your browser on localhost:3000.

Todo

* more tests
* make bower package