module ActiveAdmin::Menu::MenuNode

def [](id) 

def [](id)
  @children[normalize_id(id)]
end

def []=(id, child) 

def []=(id, child)
  @children[normalize_id(id)] = child
end

def _add(options)

If this ID is already taken, transfer the children of the existing item to the new item.
The method that actually adds new menu items. Called by the public method. 
def _add(options)
  item = ActiveAdmin::MenuItem.new(options)
  item.send :children=, self[item.id].children if self[item.id]
  self[item.id] = item
end

def add(options)


menu.add parent: 'Dashboard', label: 'My Child Dashboard'
menu.add label: 'Dashboard'
menu = Menu.new
Example 2:

end
dash.add label: 'My Child Dashboard'
menu.add label: 'Dashboard' do |dash|
menu = Menu.new
Example 1:

as shown in the below examples. Both create an identical menu structure.
Recursively builds any given menu items. There are two syntaxes supported, 
def add(options)
  item = if parent = options.delete(:parent)
    (self[parent] || add(:label => parent)).add options
  else
    _add options.merge :parent => self
  end
  yield(item) if block_given?
  item
end

def current?(item)

Used in the UI to visually distinguish which menu item is selected. 
def current?(item)
  self == item || include?(item)
end

def include?(item)

Whether any children match the given item. 
def include?(item)
  @children.values.include? item
end

def initialize 

def initialize
  @children = {}
end

def items(context = nil)

Sorts by priority first, then alphabetically by label if needed.
Returns sorted array of menu items that should be displayed in this context. 
def items(context = nil)
  @children.values.select{ |i| i.display?(context) }.sort do |a,b|
    result = a.priority       <=> b.priority
    result = a.label(context) <=> b.label(context) if result == 0
    result
  end
end

def normalize_id(id) 

def normalize_id(id)
  case id
  when String, Symbol
    id.to_s.downcase.gsub ' ', '_'
  else
    raise TypeError, "#{id.class} isn't supported as a Menu ID"
  end
end