Widget wrapper around cell

cell.rb

# app/concepts/widget/cell.rb
# A very basic "Widget" that is a container of Cell objects                           
# When rendered, it recursively renders all cells that it
# contains.
class Widget < Cell::Concept

  attr_reader :parent
  attr_reader :children

  # Create a new widget
  # All widgets are created as orphans
  def initialize(*args)
    super
    @parent = nil 
    @children = []
  end 

  # Accept an orphan widget as a child
  def <<(w)
    if w.parent.nil?
      @children << w
      w.parent = self
    else
      raise Widget::HasParent
    end 
  end 

  def show(options={})
    out = ''
    @children.each { |c| out << c.show(options) }
    out.html_safe
  end 

protected

  attr_writer :parent

end

I use this to build dynamic messaging object (flash on steroids) that is accessible from anywhere. Any method can write a message and it will be rendered in the layout.

They can do this:

    Message.now( {error: t('.failure')}, scope: 'sign_in')

which makes use of the below, where @messages is a widget cell.

    # send messages into the current action
    def now(messages, options={})
      send :now, messages, options
    end 

    def send(mode, messages, options={})
      @messages ||= Widget.new

      if messages.respond_to? :each
        messages.each do |type,text|
          case mode
          when :now
            @messages << Message::Cell.new({type => text}, options)
          when :next
            @flash[type] = text
          end 
        end 
      else
        raise InvalidMessage
      end