less.js/lib/less/plugin-api.js

(function (root, registerPlugin) { 
if (typeof define === 'function' && define.amd) { define([], registerPlugin);
} else if (typeof module === 'object' && module.exports) { module.exports = registerPlugin();
} else { if (!root.less) { root.less = {}; } if (!root.less.plugins) { root.less.plugins = []; }
root.less.plugins.push(registerPlugin()); } }

(this, function () {
    return {
        install: function(less, pluginManager, functions) {
            // functions.add('')
        }
    };
}));