less/less.js — pull request #1670 by joscha (2013-11-20 18:17:57+00:00)
Title: Allow to inject variables into a call to the parse method

This adds an additional `vars` parameter to the `parse` method. It allows a user to inject variables into a less string before compiling.
E.g.:
```javascript
var parser = new(less.Parser);
var vars = {
'my-width': '50px'
};
parser.parse('.class { width: @my-width; }', vars, function (err, tree) {
if (err) { return console.error(err) }
console.log(tree.toCSS()); // .class { width: 50px; }
});
```

This change is 100% backwards compatible.