Contributing to Less.js

Thanks for thinking about contributing! Please read the contributing instructions carefully to avoid wasted work.

### Install These Tools

- node - http://nodejs.org/
- phantomjs - http://phantomjs.org/download.html

make sure the paths are setup. If you start your favourite command line and type node -v you should see the node compiler. If you run phantomjs -v you should see the phantomjs version number.

- clone your less.js repository locally
- navigate to your local less.js repository and run npm install this installs less' npm dependencies.
### Usage

Grunt is used in order to run development commands such as tests, builds, and benchmarks. You can run them either with `grunt [command_name]` if you have `grunt-cli` installed globally or with `npm run grunt -- [command_name]`.

If you go to the root of the Less repository you should be able to do `npm test` (a handy alias for `npm run grunt -- test`) - this should run all the tests. For the browser specific only, run `npm run grunt -- browsertest` If you want to try out the current version of less against a file, from here do `node bin/lessc path/to/file.less`

To debug the browser tests, run `npm run grunt -- browsertest-server` then go to http://localhost:8088/tmp/browser/ to see the test runner pages.

Optional: To get the current version of the Less compiler do `npm -g install less` - npm is the node package manager and "-g" installs it to be available globally.

You should now be able to do `lessc file.less` and if there is an appropriate `file.less` then it will be compiled and output to the stdout. You can then compare it to running locally (`node bin/lessc file.less`).

Other grunt commands

- `npm run grunt -- benchmark` - run our benchmark tests to get some numbers on performance
- `npm run grunt` -- stable to create a new release
- `npm run grunt` -- readme to generate a new readme.md in the root directory (after each release)
### How to Run Less in Other Environments

If you look in the libs folder you will see `less`, `less-node`, `less-browser`. The less folder is pure javascript with no environment specifics. if you require less/libs/less, you get a function that takes an environment object and an array of file managers. The file managers are the same file managers that can also be written as a plugin.

```less
var createLess = require("less/libs/less"),
    myLess = createLess(environment, [myFileManager]);
```
The environment api is specified in [less/libs/less/environment/environment-api.js](https://github.com/less/less.js/blob/master/lib/less/environment/environment-api.js "less/libs/less/environment/environment-api.js") and the file manager api is specified in [less/libs/less/environment/file-manager-api.js](https://github.com/less/less.js/blob/master/lib/less/environment/file-manager-api.js "less/libs/less/environment/file-manager-api.js").

For file managers we highly recommend setting the prototype as a new AbstractFileManager - this allows you to override what is needed and allows us to implement new functions without breaking existing file managers. For an example of file managers, see the 2 node implementations, the browser implementation or the npm import plugin implementation.

### Guide

If you look at http://www.gliffy.com/go/publish/4784259, This is an overview diagram of how less works. Warning! It needs updating with v2 changes.