(function(undefined) {
  if (typeof(this.Opal) !== 'undefined') {
    console.warn('Opal already loaded. Loading twice can cause troubles, please fix your setup.');
    return this.Opal;
  }

  // The Opal object that is exposed globally
  var Opal = this.Opal = {};

  // All bridged classes - keep track to donate methods from Object
  var bridged_classes = Opal.bridged_classes = [];

  // TopScope is used for inheriting constants from the top scope
  var TopScope = function(){};

  // Opal just acts as the top scope
  TopScope.prototype = Opal;

  // To inherit scopes
  Opal.constructor = TopScope;

  // List top scope constants
  Opal.constants = [];

  // This is a useful reference to global object inside ruby files
  Opal.global = this;

  // Minify common function calls
  var $hasOwn = Opal.hasOwnProperty;
  var $slice  = Opal.slice = Array.prototype.slice;

  // Generates unique id for every ruby object
  var unique_id = 0;

  // Return next unique id
  Opal.uid = function() {
    return unique_id++;
  };

  // Table holds all class variables
  Opal.cvars = {};

  // Globals table
  Opal.gvars = {};

  // Get constants
  Opal.get = function(name) {
    var constant = this[name];

    if (constant == null) {
      return this.base.$const_missing(name);
    }

    return constant;
  };

  /*
   * Create a new constants scope for the given class with the given
   * base. Constants are looked up through their parents, so the base
   * scope will be the outer scope of the new klass.
   */
  function create_scope(base, klass, id) {
    var const_alloc = function() {};
    var const_scope = const_alloc.prototype = new base.constructor();

    klass.$$scope       = const_scope;
    klass.$$base_module = base.base;

    const_scope.base        = klass;
    const_scope.constructor = const_alloc;
    const_scope.constants   = [];

    if (id) {
      klass.$$orig_scope = base;
      base[id] = base.constructor[id] = klass;
      base.constants.push(id);
    }
  }

  Opal.create_scope = create_scope;

  /*
   * A `class Foo; end` expression in ruby is compiled to call this runtime
   * method which either returns an existing class of the given name, or creates
   * a new class in the given `base` scope.
   *
   * If a constant with the given name exists, then we check to make sure that
   * it is a class and also that the superclasses match. If either of these
   * fail, then we raise a `TypeError`. Note, superklass may be null if one was
   * not specified in the ruby code.
   *
   * We pass a constructor to this method of the form `function ClassName() {}`
   * simply so that classes show up with nicely formatted names inside debuggers
   * in the web browser (or node/sprockets).
   *
   * The `base` is the current `self` value where the class is being created
   * from. We use this to get the scope for where the class should be created.
   * If `base` is an object (not a class/module), we simple get its class and
   * use that as the base instead.
   *
   * @param [Object] base where the class is being created
   * @param [Class] superklass superclass of the new class (may be null)
   * @param [String] id the name of the class to be created
   * @param [Function] constructor function to use as constructor
   * @return [Class] new or existing ruby class
   */
  Opal.klass = function(base, superklass, id, constructor) {
    // If base is an object, use its class
    if (!base.$$is_class) {
      base = base.$$class;
    }

    // Not specifying a superclass means we can assume it to be Object
    if (superklass === null) {
      superklass = ObjectClass;
    }

    var klass = base.$$scope[id];

    // If a constant exists in the scope, then we must use that
    if ($hasOwn.call(base.$$scope, id) && klass.$$orig_scope === base.$$scope) {
      // Make sure the existing constant is a class, or raise error
      if (!klass.$$is_class) {
        throw Opal.TypeError.$new(id + " is not a class");
      }

      // Make sure existing class has same superclass
      if (superklass !== klass.$$super && superklass !== ObjectClass) {
        throw Opal.TypeError.$new("superclass mismatch for class " + id);
      }
    }
    else if (typeof(superklass) === 'function') {
      // passed native constructor as superklass, so bridge it as ruby class
      return bridge_class(id, superklass);
    }
    else {
      // if class doesnt exist, create a new one with given superclass
      klass = boot_class(superklass, constructor);

      // name class using base (e.g. Foo or Foo::Baz)
      klass.$$name = id;

      // every class gets its own constant scope, inherited from current scope
      create_scope(base.$$scope, klass, id);

      // Name new class directly onto current scope (Opal.Foo.Baz = klass)
      base[id] = base.$$scope[id] = klass;

      // Copy all parent constants to child, unless parent is Object
      if (superklass !== ObjectClass && superklass !== BasicObjectClass) {
        Opal.donate_constants(superklass, klass);
      }

      // call .inherited() hook with new class on the superclass
      if (superklass.$inherited) {
        superklass.$inherited(klass);
      }
    }

    return klass;
  };

  // Create generic class with given superclass.
  function boot_class(superklass, constructor) {
    var alloc = boot_class_alloc(null, constructor, superklass)

    return boot_class_object(superklass, alloc);
  }

  // Make `boot_class` available to the JS-API
  Opal.boot = boot_class;

  /*
   * The class object itself (as in `Class.new`)
   *
   * @param [(Opal) Class] superklass Another class object (as in `Class.new`)
   * @param [constructor]  alloc      The constructor that holds the prototype
   *                                  that will be used for instances of the
   *                                  newly constructed class.
   */
  function boot_class_object(superklass, alloc) {
    var singleton_class = function() {};
    singleton_class.prototype = superklass.constructor.prototype;

    function OpalClass() {}
    OpalClass.prototype = new singleton_class();

    var klass = new OpalClass();

    setup_module_or_class_object(klass, OpalClass, superklass, alloc.prototype);

    // @property $$alloc This is the constructor of instances of the current
    //                   class. Its prototype will be used for method lookup
    klass.$$alloc = alloc;

    // @property $$proto.$$class Make available to instances a reference to the
    //                           class they belong to.
    klass.$$proto.$$class = klass;

    return klass;
  }

  /*
   * Adds common/required properties to a module or class object
   * (as in `Module.new` / `Class.new`)
   *
   * @param module      The module or class that needs to be prepared
   *
   * @param constructor The constructor of the module or class itself,
   *                    usually it's already assigned by using `new`. Some
   *                    ipothesis on why it's needed can be found below.
   *
   * @param superklass  The superclass of the class/module object, for modules
   *                    is `Module` (of `ModuleClass` in JS context)
   *
   * @param prototype   The prototype on which the class/module methods will
   *                    be stored.
   */
  function setup_module_or_class_object(module, constructor, superklass, prototype) {
    // @property $$id Each class is assigned a unique `id` that helps
    //                comparation and implementation of `#object_id`
    module.$$id = unique_id++;

    // @property $$proto This is the prototype on which methods will be defined
    module.$$proto = prototype;

    // @property constructor keeps a ref to the constructor, but apparently the
    //                       constructor is already set on:
    //
    //                          `var module = new constructor` is called.
    //
    //                       Maybe there are some browsers not abiding (IE6?)
    module.constructor = constructor;

    // @property $$is_class Clearly mark this as a class-like
    module.$$is_class = true;

    // @property $$super the superclass, doesn't get changed by module inclusions
    module.$$super = superklass;

    // @property $$parent direct parent class or module
    //                    starts with the superclass, after module inclusion is
    //                    the last included module
    module.$$parent = superklass;

    // @property $$methods keeps track of methods defined on the class
    //                     but seems to be used just by `define_basic_object_method`
    //                     and for donating (Ruby) Object methods to bridged classes
    //                     TODO: check if it can be removed
    module.$$methods = [];

    // @property $$inc included modules
    module.$$inc = [];
  }

  // Define new module (or return existing module)
  Opal.module = function(base, id) {
    var module;

    if (!base.$$is_class) {
      base = base.$$class;
    }

    if ($hasOwn.call(base.$$scope, id)) {
      module = base.$$scope[id];

      if (!module.$$is_mod && module !== ObjectClass) {
        throw Opal.TypeError.$new(id + " is not a module");
      }
    }
    else {
      module = boot_module_object();
      module.$$name = id;

      create_scope(base.$$scope, module, id);

      // Name new module directly onto current scope (Opal.Foo.Baz = module)
      base[id] = base.$$scope[id] = module;
    }

    return module;
  };

  /*
   * Internal function to create a new module instance. This simply sets up
   * the prototype hierarchy and method tables.
   */
  function boot_module_object() {
    var mtor = function() {};
    mtor.prototype = ModuleClass.constructor.prototype;

    function module_constructor() {}
    module_constructor.prototype = new mtor();

    var module = new module_constructor();
    var module_prototype = {};

    setup_module_or_class_object(module, module_constructor, ModuleClass, module_prototype);

    module.$$is_mod = true;
    module.$$dep    = [];

    return module;
  }

  /*
   * Get (or prepare) the singleton class for the passed object.
   *
   * @param object [Ruby Object]
   */
  Opal.get_singleton_class = function(object) {
    if (object.$$meta) {
      return object.$$meta;
    }

    if (object.$$is_class) {
      return build_class_singleton_class(object);
    }

    return build_object_singleton_class(object);
  };

  /*
   * Build the singleton class for an existing class.
   *
   * NOTE: Actually in MRI a class' singleton class inherits from its
   * superclass' singleton class which in turn inherits from Class;
   */
  function build_class_singleton_class(klass) {
    var meta = new Opal.Class.$$alloc;

    meta.$$class = Opal.Class;
    meta.$$proto = klass.constructor.prototype;

    meta.$$is_singleton = true;
    meta.$$inc          = [];
    meta.$$methods      = [];
    meta.$$scope        = klass.$$scope;

    return klass.$$meta = meta;
  }

  /*
   * Build the singleton class for a Ruby (non class) Object.
   */
  function build_object_singleton_class(object) {
    var orig_class = object.$$class,
        class_id   = "#<Class:#<" + orig_class.$$name + ":" + orig_class.$$id + ">>";

    var Singleton = function () {};
    var meta = Opal.boot(orig_class, Singleton);
    meta.$$name   = class_id;

    meta.$$proto  = object;
    meta.$$class  = orig_class.$$class;
    meta.$$scope  = orig_class.$$scope;
    meta.$$parent = orig_class;
    return object.$$meta = meta;
  }

  /*
   * The actual inclusion of a module into a class.
   */
  Opal.append_features = function(module, klass) {
    var included = klass.$$inc;

    // check if this module is already included in the klass
    for (var j = 0, jj = included.length; j < jj; j++) {
      if (included[j] === module) {
        return;
      }
    }

    included.push(module);
    module.$$dep.push(klass);

    // iclass
    var iclass = {
      $$name:   module.$$name,
      $$proto:  module.$$proto,
      $$parent: klass.$$parent,
      $$module: module,
      $$iclass: true
    };

    klass.$$parent = iclass;

    var donator   = module.$$proto,
        prototype = klass.$$proto,
        methods   = module.$$methods;

    for (var i = 0, length = methods.length; i < length; i++) {
      var method = methods[i], current;


      if ( prototype.hasOwnProperty(method) &&
          !(current = prototype[method]).$$donated && !current.$$stub ) {
        // if the target class already has a method of the same name defined
        // and that method was NOT donated, then it must be a method defined
        // by the class so we do not want to override it
      }
      else {
        prototype[method] = donator[method];
        prototype[method].$$donated = true;
      }
    }

    if (klass.$$dep) {
      Opal.donate(klass, methods.slice(), true);
    }

    Opal.donate_constants(module, klass);
  };

  // Boot a base class (makes instances).
  function boot_class_alloc(id, constructor, superklass) {
    if (superklass) {
      var ctor = function() {};
          ctor.prototype   = superklass.$$proto || superklass.prototype;

      if (id) {
        ctor.displayName = id;
      }

      constructor.prototype = new ctor();
    }

    constructor.prototype.constructor = constructor;

    return constructor;
  }

  /*
   * Builds the class object for core classes:
   * - make the class object have a singleton class
   * - make the singleton class inherit from its parent singleton class
   *
   * @param id         [String]      the name of the class
   * @param alloc      [Function]    the constructor for the core class instances
   * @param superclass [Class alloc] the constructor of the superclass
   */
  function boot_core_class_object(id, alloc, superclass) {
    var superclass_constructor = function() {};
        superclass_constructor.prototype = superclass.prototype;

    var singleton_class = function() {};
        singleton_class.prototype = new superclass_constructor();

    singleton_class.displayName = "#<Class:"+id+">";

    // the singleton_class acts as the class object constructor
    var klass = new singleton_class();

    setup_module_or_class_object(klass, singleton_class, superclass, alloc.prototype);

    klass.$$alloc = alloc;
    klass.$$name  = id;

    // Give all instances a ref to their class
    alloc.prototype.$$class = klass;

    Opal[id] = klass;
    Opal.constants.push(id);

    return klass;
  }

  /*
   * For performance, some core ruby classes are toll-free bridged to their
   * native javascript counterparts (e.g. a ruby Array is a javascript Array).
   *
   * This method is used to setup a native constructor (e.g. Array), to have
   * its prototype act like a normal ruby class. Firstly, a new ruby class is
   * created using the native constructor so that its prototype is set as the
   * target for th new class. Note: all bridged classes are set to inherit
   * from Object.
   *
   * Bridged classes are tracked in `bridged_classes` array so that methods
   * defined on Object can be "donated" to all bridged classes. This allows
   * us to fake the inheritance of a native prototype from our Object
   * prototype.
   *
   * Example:
   *
   *    bridge_class("Proc", Function);
   *
   * @param [String] name the name of the ruby class to create
   * @param [Function] constructor native javascript constructor to use
   * @return [Class] returns new ruby class
   */
  function bridge_class(name, constructor) {
    var klass = boot_class_object(ObjectClass, constructor);

    klass.$$name = name;

    create_scope(Opal, klass, name);
    bridged_classes.push(klass);

    var object_methods = BasicObjectClass.$$methods.concat(ObjectClass.$$methods);

    for (var i = 0, len = object_methods.length; i < len; i++) {
      var meth = object_methods[i];
      constructor.prototype[meth] = ObjectClass.$$proto[meth];
    }

    add_stubs_subscriber(constructor.prototype);

    return klass;
  }

  /*
   * constant assign
   */
  Opal.casgn = function(base_module, name, value) {
    var scope = base_module.$$scope;

    if (value.$$is_class && value.$$name === nil) {
      value.$$name = name;
    }

    if (value.$$is_class) {
      value.$$base_module = base_module;
    }

    scope.constants.push(name);
    return scope[name] = value;
  };

  /*
   * constant decl
   */
  Opal.cdecl = function(base_scope, name, value) {
    base_scope.constants.push(name);
    return base_scope[name] = value;
  };

  /*
   * constant get
   */
  Opal.cget = function(base_scope, path) {
    if (path == null) {
      path       = base_scope;
      base_scope = Opal.Object;
    }

    var result = base_scope;

    path = path.split('::');
    while (path.length !== 0) {
      result = result.$const_get(path.shift());
    }

    return result;
  };

  /*
   * When a source module is included into the target module, we must also copy
   * its constants to the target.
   */
  Opal.donate_constants = function(source_mod, target_mod) {
    var source_constants = source_mod.$$scope.constants,
        target_scope     = target_mod.$$scope,
        target_constants = target_scope.constants;

    for (var i = 0, length = source_constants.length; i < length; i++) {
      target_constants.push(source_constants[i]);
      target_scope[source_constants[i]] = source_mod.$$scope[source_constants[i]];
    }
  };

  /*
   * Methods stubs are used to facilitate method_missing in opal. A stub is a
   * placeholder function which just calls `method_missing` on the receiver.
   * If no method with the given name is actually defined on an object, then it
   * is obvious to say that the stub will be called instead, and then in turn
   * method_missing will be called.
   *
   * When a file in ruby gets compiled to javascript, it includes a call to
   * this function which adds stubs for every method name in the compiled file.
   * It should then be safe to assume that method_missing will work for any
   * method call detected.
   *
   * Method stubs are added to the BasicObject prototype, which every other
   * ruby object inherits, so all objects should handle method missing. A stub
   * is only added if the given property name (method name) is not already
   * defined.
   *
   * Note: all ruby methods have a `$` prefix in javascript, so all stubs will
   * have this prefix as well (to make this method more performant).
   *
   *    Opal.add_stubs(["$foo", "$bar", "$baz="]);
   *
   * All stub functions will have a private `$$stub` property set to true so
   * that other internal methods can detect if a method is just a stub or not.
   * `Kernel#respond_to?` uses this property to detect a methods presence.
   *
   * @param [Array] stubs an array of method stubs to add
   */
  Opal.add_stubs = function(stubs) {
    var subscribers = Opal.stub_subscribers;
    var subscriber;

    for (var i = 0, length = stubs.length; i < length; i++) {
      var method_name = stubs[i], stub = stub_for(method_name);

      for (var j = 0; j < subscribers.length; j++) {
        subscriber = subscribers[j];
        if (!(method_name in subscriber)) {
          subscriber[method_name] = stub;
        }
      }
    }
  };

  /*
   * Add a prototype to the subscribers list, and (TODO) add previously stubbed
   * methods.
   *
   * @param [Prototype]
   */
  function add_stubs_subscriber(prototype) {
    // TODO: Add previously stubbed methods too.
    Opal.stub_subscribers.push(prototype);
  }

  /*
   * Keep a list of prototypes that want method_missing stubs to be added.
   *
   * @default [Prototype List] BasicObject.prototype
   */
  Opal.stub_subscribers = [BasicObject.prototype];

  /*
   * Add a method_missing stub function to the given prototype for the
   * given name.
   *
   * @param [Prototype] prototype the target prototype
   * @param [String] stub stub name to add (e.g. "$foo")
   */
  function add_stub_for(prototype, stub) {
    var method_missing_stub = stub_for(stub);
    prototype[stub] = method_missing_stub;
  }

  /*
   * Generate the method_missing stub for a given method name.
   *
   * @param [String] method_name The js-name of the method to stub (e.g. "$foo")
   */
  function stub_for(method_name) {
    function method_missing_stub() {
      // Copy any given block onto the method_missing dispatcher
      this.$method_missing.$$p = method_missing_stub.$$p;

      // Set block property to null ready for the next call (stop false-positives)
      method_missing_stub.$$p = null;

      // call method missing with correct args (remove '$' prefix on method name)
      return this.$method_missing.apply(this, [method_name.slice(1)].concat($slice.call(arguments)));
    }

    method_missing_stub.$$stub = true;

    return method_missing_stub;
  }

  // Expose for other parts of Opal to use
  Opal.add_stub_for = add_stub_for;

  // Arity count error dispatcher
  Opal.ac = function(actual, expected, object, meth) {
    var inspect = (object.$$is_class ? object.$$name + '.' : object.$$class.$$name + '#') + meth;
    var msg = '[' + inspect + '] wrong number of arguments(' + actual + ' for ' + expected + ')';
    throw Opal.ArgumentError.$new(msg);
  };

  // Super dispatcher
  Opal.find_super_dispatcher = function(obj, jsid, current_func, iter, defs) {
    var dispatcher;

    if (defs) {
      dispatcher = obj.$$is_class ? defs.$$super : obj.$$class.$$proto;
    }
    else {
      if (obj.$$is_class) {
        dispatcher = obj.$$super;
      }
      else {
        dispatcher = find_obj_super_dispatcher(obj, jsid, current_func);
      }
    }

    dispatcher = dispatcher['$' + jsid];
    dispatcher.$$p = iter;

    return dispatcher;
  };

  // Iter dispatcher for super in a block
  Opal.find_iter_super_dispatcher = function(obj, jsid, current_func, iter, defs) {
    if (current_func.$$def) {
      return Opal.find_super_dispatcher(obj, current_func.$$jsid, current_func, iter, defs);
    }
    else {
      return Opal.find_super_dispatcher(obj, jsid, current_func, iter, defs);
    }
  };

  function find_obj_super_dispatcher(obj, jsid, current_func) {
    var klass = obj.$$meta || obj.$$class;
    jsid = '$' + jsid;

    while (klass) {
      if (klass.$$proto[jsid] === current_func) {
        // ok
        break;
      }

      klass = klass.$$parent;
    }

    // if we arent in a class, we couldnt find current?
    if (!klass) {
      throw new Error("could not find current class for super()");
    }

    klass = klass.$$parent;

    // else, let's find the next one
    while (klass) {
      var working = klass.$$proto[jsid];

      if (working && working !== current_func) {
        // ok
        break;
      }

      klass = klass.$$parent;
    }

    return klass.$$proto;
  };

  /*
   * Used to return as an expression. Sometimes, we can't simply return from
   * a javascript function as if we were a method, as the return is used as
   * an expression, or even inside a block which must "return" to the outer
   * method. This helper simply throws an error which is then caught by the
   * method. This approach is expensive, so it is only used when absolutely
   * needed.
   */
  Opal.ret = function(val) {
    Opal.returner.$v = val;
    throw Opal.returner;
  };

  // handles yield calls for 1 yielded arg
  Opal.yield1 = function(block, arg) {
    if (typeof(block) !== "function") {
      throw Opal.LocalJumpError.$new("no block given");
    }

    if (block.length > 1 && arg.$$is_array) {
      return block.apply(null, arg);
    }
    else {
      return block(arg);
    }
  };

  // handles yield for > 1 yielded arg
  Opal.yieldX = function(block, args) {
    if (typeof(block) !== "function") {
      throw Opal.LocalJumpError.$new("no block given");
    }

    if (block.length > 1 && args.length == 1) {
      if (args[0].$$is_array) {
        return block.apply(null, args[0]);
      }
    }

    if (!args.$$is_array) {
      args = $slice.call(args);
    }

    return block.apply(null, args);
  };

  // Finds the corresponding exception match in candidates.  Each candidate can
  // be a value, or an array of values.  Returns null if not found.
  Opal.rescue = function(exception, candidates) {
    for (var i = 0; i < candidates.length; i++) {
      var candidate = candidates[i];

      if (candidate.$$is_array) {
        var result = Opal.rescue(exception, candidate);

        if (result) {
          return result;
        }
      }
      else if (candidate['$==='](exception)) {
        return candidate;
      }
    }

    return null;
  };

  Opal.is_a = function(object, klass) {
    if (object.$$meta === klass) {
      return true;
    }

    var search = object.$$class;

    while (search) {
      if (search === klass) {
        return true;
      }

      for (var i = 0, length = search.$$inc.length; i < length; i++) {
        if (search.$$inc[i] == klass) {
          return true;
        }
      }

      search = search.$$super;
    }

    return false;
  };

  // Helper to convert the given object to an array
  Opal.to_ary = function(value) {
    if (value.$$is_array) {
      return value;
    }
    else if (value.$to_ary && !value.$to_ary.$$stub) {
      return value.$to_ary();
    }

    return [value];
  };

  /*
   * Call a ruby method on a ruby object with some arguments:
   *
   *   var my_array = [1, 2, 3, 4]
   *   Opal.send(my_array, 'length')     # => 4
   *   Opal.send(my_array, 'reverse!')   # => [4, 3, 2, 1]
   *
   * A missing method will be forwarded to the object via
   * method_missing.
   *
   * The result of either call with be returned.
   *
   * @param [Object] recv the ruby object
   * @param [String] mid ruby method to call
   */
  Opal.send = function(recv, mid) {
    var args = $slice.call(arguments, 2),
        func = recv['$' + mid];

    if (func) {
      return func.apply(recv, args);
    }

    return recv.$method_missing.apply(recv, [mid].concat(args));
  };

  Opal.block_send = function(recv, mid, block) {
    var args = $slice.call(arguments, 3),
        func = recv['$' + mid];

    if (func) {
      func.$$p = block;
      return func.apply(recv, args);
    }

    return recv.$method_missing.apply(recv, [mid].concat(args));
  };

  /*
   * Donate methods for a class/module
   */
  Opal.donate = function(klass, defined, indirect) {
    var methods = klass.$$methods, included_in = klass.$$dep;

    // if (!indirect) {
      klass.$$methods = methods.concat(defined);
    // }

    if (included_in) {
      for (var i = 0, length = included_in.length; i < length; i++) {
        var includee = included_in[i];
        var dest     = includee.$$proto;

        for (var j = 0, jj = defined.length; j < jj; j++) {
          var method = defined[j];

          dest[method] = klass.$$proto[method];
          dest[method].$$donated = true;
        }

        if (includee.$$dep) {
          Opal.donate(includee, defined, true);
        }
      }
    }
  };

  Opal.defn = function(obj, jsid, body) {
    if (obj.$$is_mod) {
      obj.$$proto[jsid] = body;
      Opal.donate(obj, [jsid]);

      if (obj.$$module_function) {
        obj[jsid] = body;
      }
    }
    else if (obj.$$is_class) {
      obj.$$proto[jsid] = body;

      if (obj === BasicObjectClass) {
        define_basic_object_method(jsid, body);
      }
      else if (obj === ObjectClass) {
        Opal.donate(obj, [jsid]);
      }
    }
    else {
      obj[jsid] = body;
    }

    return nil;
  };

  /*
   * Define a singleton method on the given object.
   */
  Opal.defs = function(obj, jsid, body) {
    if (obj.$$is_class || obj.$$is_mod) {
      obj.constructor.prototype[jsid] = body;
    }
    else {
      obj[jsid] = body;
    }
  };

  function define_basic_object_method(jsid, body) {
    BasicObjectClass.$$methods.push(jsid);
    for (var i = 0, len = bridged_classes.length; i < len; i++) {
      bridged_classes[i].$$proto[jsid] = body;
    }
  }

  Opal.hash = function() {
    if (arguments.length == 1 && arguments[0].$$class == Opal.Hash) {
      return arguments[0];
    }

    var hash = new Opal.Hash.$$alloc(),
        keys = [],
        _map = {},
        smap = {},
        key, obj, length, khash;

    hash.map   = _map;
    hash.smap  = smap;
    hash.keys  = keys;

    if (arguments.length == 1) {
      if (arguments[0].$$is_array) {
        var args = arguments[0];

        for (var i = 0, ii = args.length; i < ii; i++) {
          var pair = args[i];

          if (pair.length !== 2) {
            throw Opal.ArgumentError.$new("value not of length 2: " + pair.$inspect());
          }

          key = pair[0];
          obj = pair[1];

          if (key.$$is_string) {
            khash = key;
            map = smap;
          } else {
            khash = key.$hash();
            map = _map;
          }

          if (map[khash] == null) {
            keys.push(key);
          }

          map[khash] = obj;
        }
      }
      else {
        obj = arguments[0];
        for (key in obj) {
          khash = key.$hash();
          map[khash] = obj[khash];
          keys.push(key);
        }
      }
    }
    else {
      length = arguments.length;
      if (length % 2 !== 0) {
        throw Opal.ArgumentError.$new("odd number of arguments for Hash");
      }

      for (var j = 0; j < length; j++) {
        key = arguments[j];
        obj = arguments[++j];

        if (key.$$is_string) {
          khash = key;
          map = smap;
        } else {
          khash = key.$hash();
          map = _map;
        }

        if (map[khash] == null) {
          keys.push(key);
        }

        map[khash] = obj;
      }
    }

    return hash;
  };

  /*
   * hash2 is a faster creator for hashes that just use symbols and
   * strings as keys. The map and keys array can be constructed at
   * compile time, so they are just added here by the constructor
   * function
   */
  Opal.hash2 = function(keys, map) {
    var hash = new Opal.Hash.$$alloc();

    hash.keys = keys;
    hash.map  = {};
    hash.smap = map;

    return hash;
  };

  /*
   * Create a new range instance with first and last values, and whether the
   * range excludes the last value.
   */
  Opal.range = function(first, last, exc) {
    var range         = new Opal.Range.$$alloc();
        range.begin   = first;
        range.end     = last;
        range.exclude = exc;

    return range;
  };

  // Require system
  // --------------
  (function(Opal) {
    var loaded_features = ['corelib/runtime.js'],
        require_table   = {'corelib/runtime.js': true},
        modules         = {};

    var current_dir  = '.';

    function mark_as_loaded(filename) {
      if (require_table[filename]) {
        return false;
      }

      loaded_features.push(filename);
      require_table[filename] = true;

      return true;
    }

    function normalize_loadable_path(path) {
      var parts, part, new_parts = [], SEPARATOR = '/';

      if (current_dir !== '.') {
        path = current_dir.replace(/\/*$/, '/') + path;
      }

      parts = path.split(SEPARATOR);

      for (var i = 0, ii = parts.length; i < ii; i++) {
        part = parts[i];
        if (part == '') continue;
        (part === '..') ? new_parts.pop() : new_parts.push(part)
      }

      return new_parts.join(SEPARATOR);
    }

    function load(path) {
      mark_as_loaded(path);

      var module = modules[path];

      if (module) {
        module(Opal);
      }
      else {
        var severity = Opal.dynamic_require_severity || 'warning';
        var message  = 'cannot load such file -- ' + path;

        if (severity === "error") {
          Opal.LoadError ? Opal.LoadError.$new(message) : function(){throw message}();
        }
        else if (severity === "warning") {
          console.warn('WARNING: LoadError: ' + message);
        }
      }

      return true;
    }

    function require(path) {
      if (require_table[path]) {
        return false;
      }

      return load(path);
    }

    Opal.modules         = modules;
    Opal.loaded_features = loaded_features;

    Opal.normalize_loadable_path = normalize_loadable_path;
    Opal.mark_as_loaded          = mark_as_loaded;

    Opal.load    = load;
    Opal.require = require;
  })(Opal);

  // Initialization
  // --------------

  // The actual class for BasicObject
  var BasicObjectClass;

  // The actual Object class
  var ObjectClass;

  // The actual Module class
  var ModuleClass;

  // The actual Class class
  var ClassClass;

  // Constructor for instances of BasicObject
  function BasicObject(){}

  // Constructor for instances of Object
  function Object(){}

  // Constructor for instances of Class
  function Class(){}

  // Constructor for instances of Module
  function Module(){}

  // Constructor for instances of NilClass (nil)
  function NilClass(){}

  // Constructors for *instances* of core objects
  boot_class_alloc('BasicObject', BasicObject);
  boot_class_alloc('Object',      Object,       BasicObject);
  boot_class_alloc('Module',      Module,       Object);
  boot_class_alloc('Class',       Class,        Module);

  // Constructors for *classes* of core objects
  BasicObjectClass = boot_core_class_object('BasicObject', BasicObject, Class);
  ObjectClass      = boot_core_class_object('Object',      Object,      BasicObjectClass.constructor);
  ModuleClass      = boot_core_class_object('Module',      Module,      ObjectClass.constructor);
  ClassClass       = boot_core_class_object('Class',       Class,       ModuleClass.constructor);

  // Fix booted classes to use their metaclass
  BasicObjectClass.$$class = ClassClass;
  ObjectClass.$$class      = ClassClass;
  ModuleClass.$$class      = ClassClass;
  ClassClass.$$class       = ClassClass;

  // Fix superclasses of booted classes
  BasicObjectClass.$$super = null;
  ObjectClass.$$super      = BasicObjectClass;
  ModuleClass.$$super      = ObjectClass;
  ClassClass.$$super       = ModuleClass;

  BasicObjectClass.$$parent = null;
  ObjectClass.$$parent      = BasicObjectClass;
  ModuleClass.$$parent      = ObjectClass;
  ClassClass.$$parent       = ModuleClass;

  // Internally, Object acts like a module as it is "included" into bridged
  // classes. In other words, we donate methods from Object into our bridged
  // classes as their prototypes don't inherit from our root Object, so they
  // act like module includes.
  ObjectClass.$$dep = bridged_classes;

  Opal.base                     = ObjectClass;
  BasicObjectClass.$$scope      = ObjectClass.$$scope = Opal;
  BasicObjectClass.$$orig_scope = ObjectClass.$$orig_scope = Opal;
  Opal.Kernel                   = ObjectClass;

  ModuleClass.$$scope      = ObjectClass.$$scope;
  ModuleClass.$$orig_scope = ObjectClass.$$orig_scope;
  ClassClass.$$scope       = ObjectClass.$$scope;
  ClassClass.$$orig_scope  = ObjectClass.$$orig_scope;

  ObjectClass.$$proto.toString = function() {
    return this.$to_s();
  };

  ObjectClass.$$proto.$require = Opal.require;

  Opal.top = new ObjectClass.$$alloc();

  // Nil
  var nil_id = Opal.uid(); // nil id is traditionally 4
  Opal.klass(ObjectClass, ObjectClass, 'NilClass', NilClass);
  var nil = Opal.nil = new NilClass();
  nil.$$id = nil_id;
  nil.call = nil.apply = function() { throw Opal.LocalJumpError.$new('no block given'); };

  Opal.breaker  = new Error('unexpected break');
  Opal.returner = new Error('unexpected return');

  bridge_class('Array',     Array);
  bridge_class('Boolean',   Boolean);
  bridge_class('Numeric',   Number);
  bridge_class('String',    String);
  bridge_class('Proc',      Function);
  bridge_class('Exception', Error);
  bridge_class('Regexp',    RegExp);
  bridge_class('Time',      Date);

  TypeError.$$super = Error;
}).call(this);

if (typeof(global) !== 'undefined') {
  global.Opal = this.Opal;
  Opal.global = global;
}
if (typeof(window) !== 'undefined') {
  window.Opal = this.Opal;
  Opal.global = window;
}