A Lotus::View sneak peek: Lotus::Presenter

lotus_presenter.rb

module Lotus
  module Presenter
    def initialize(object)
      @object = object
    end

    protected
    def method_missing(m, *args, &blk)
      if @object.respond_to?(m)
        @object.__send__ m, *args, &blk
      else
        super
      end
    end
  end
end

class Map
  attr_reader :locations

  def initialize(locations)
    @locations = locations
  end

  def location_names
    @locations.join(', ')
  end
end

class MapPresenter
  include Lotus::Presenter

  def count
    locations.count
  end

  def location_names
    super.upcase
  end

  def inspect_object
    @object.inspect
  end
end

map = Map.new(['Rome', 'Boston'])
presenter = MapPresenter.new(map)

# access a map method
puts presenter.locations # => ['Rome', 'Boston']

# access presenter concrete methods
puts presenter.count # => 1

# uses super to access original object implementation
puts presenter.location_names # => 'ROME, BOSTON'

# it has private access to the original object
puts presenter.inspect_object # => #<Map:0x007fdeada0b2f0 @locations=["Rome", "Boston"]>

Beautiful! You've actually built the project I've never gotten to finish, a Ruby MVP framework of OO purity.

I'm hoping you're doing what I'd do, only allow presenter objects to be locally accessible to template rendering scope which would remove Rails ugly Controller "helper" mismatch. If only my current project was built with this. :drool:

@ cheapRoc The way I use presenters are to instantiate them in the view.

require 'lotus/view'

module Dashboard
  class Index
    include Lotus::View

    def map
      MapPresenter.new(...)
    end
  end
end

and use in the template:

<p><%= map.location_names %></p>