Coffeescript inheritance.

gistfile1.js

__extends = function(child, parent) { 
  __hasProp = {}.hasOwnProperty

  for (var key in parent) { 
    if (__hasProp.call(parent, key)) 
      child[key] = parent[key]; 
  } 

  function ctor() { 
    this.constructor = child;
  } 

  ctor.prototype = parent.prototype; 
  child.prototype = new ctor(); 
  child.__super__ = parent.prototype; 
  return child; 
};