jison

Jison
=====
* issues
* discuss


An API for creating parsers in JavaScript
-----------------------------------------

Jison generates bottom-up parsers in JavaScript. Its API is similar to Bison's, hence the name. It supports many of Bison's major features, plus some of its own. If you are new to parser generators such as Bison, and Context-free Grammars in general, a [good introduction][1] is found in the Bison manual. If you already know Bison, Jison should be easy to pickup.

Briefly, Jison takes a JSON encoded grammar or Bison style grammar and outputs a JavaScript file capable of parsing the language described by that grammar. You can then use the generated script to parse inputs and accept, reject, or perform actions based on the input.

Installation
------------
Jison can be installed for Node using npm

Using npm:

npm install jison -g

Usage from the command line
-----------------------

Clone the github repository for examples:

git clone git://github.com/zaach/jison.git
cd jison/examples

Now you're ready to generate some parsers:

jison calculator.jison

This will generate calculator.js in your current working directory. This file can be used to parse an input file, like so:

echo "2^32 / 1024" > testcalc
node calculator.js testcalc

This will print out 4194304.

Full cli option list:

Usage: jison [file] [lexfile] [options]

file file containing a grammar
lexfile file containing a lexical grammar

Options:
-j, --json force jison to expect a grammar in JSON format
-o FILE, --outfile FILE Filename and base module name of the generated parser
-t, --debug Debug mode
-m TYPE, --module-type TYPE The type of module to generate (commonjs, amd, js)
-p TYPE, --parser-type TYPE The type of algorithm to use for the parser (lr0, slr, lalr, lr)
-V, --version print version and exit

Usage from a CommonJS module
--------------------------

You can generate parsers programatically from JavaScript as well. Assuming Jison is in your commonjs environment's load path:

``javascript
// mygenerator.js
var Parser = require("jison").Parser;

// a grammar in JSON
var grammar = {
"lex": {
"rules": [
["\\s+", "/ skip whitespace /"],
["[a-f0-9]+", "return 'HEX';"]
]
},

"bnf": {
"hex_strings" :[ "hex_strings HEX",
"HEX" ]
}
};

// grammar can also be a string that uses jison's grammar format
var parser = new Parser(grammar);

// generate source, ready to be written to disk
var parserSource = parser.generate();

// you can also use the parser directly from memory

// returns true
parser.parse("adfe34bc e82a");

// throws lexical error
parser.parse("adfe34bc zxg");
``

More Documentation
------------------
For more information on creating grammars and using the generated parsers, read the documentation.

How to contribute
-----------------

See CONTRIBUTING.md for contribution guidelines, how to run the tests, etc.

Projects using Jison
------------------

View them on the wiki, or add your own.

Contributors
------------
Githubbers

Special thanks to Jarred Ligatti, Manuel E. Bermúdez

License
-------

> Copyright (c) 2009-2014 Zachary Carter
>
> Permission is hereby granted, free of
> charge, to any person obtaining a
> copy of this software and associated
> documentation files (the "Software"),
> to deal in the Software without
> restriction, including without
> limitation the rights to use, copy,
> modify, merge, publish, distribute,
> sublicense, and/or sell copies of the
> Software, and to permit persons to
> whom the Software is furnished to do
> so, subject to the following
> conditions:
>
> The above copyright notice and this
> permission notice shall be included
> in all copies or substantial portions
> of the Software.
>
> THE SOFTWARE IS PROVIDED "AS IS",
> WITHOUT WARRANTY OF ANY KIND, EXPRESS
> OR IMPLIED, INCLUDING BUT NOT LIMITED
> TO THE WARRANTIES OF MERCHANTABILITY,
> FITNESS FOR A PARTICULAR PURPOSE AND
> NONINFRINGEMENT. IN NO EVENT SHALL THE
> AUTHORS OR COPYRIGHT HOLDERS BE
> LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> LIABILITY, WHETHER IN AN ACTION OF
> CONTRACT, TORT OR OTHERWISE, ARISING
> FROM, OUT OF OR IN CONNECTION WITH THE
> SOFTWARE OR THE USE OR OTHER DEALINGS
> IN THE SOFTWARE.

[1]: http://dinosaur.compilertools.net/bison/bison_4.html