object @post
node :categories do |post|
  post.categories.map do |category| 
    partial("categories/show", :object => category) 
  end
end

object @post
child :categories do
  extends "categories/show"
end

# products/show.rabl
attributes :name, :dimensions, :weight, :price
# free_products/show.rabl
extends "products/show", except: :price

node :car do
  extends "cars/show", object: car
end

# users/show.rabl
object @presentation
node :blogger do
  partial "writers/info", object: presentation.blogger
end
node :author do
  partial "writers/info", object: presentation.author
end
# writers/_info.rabl
object @writer  # ignored when used as a partial so I usually don't specify it
attributes :name, :first_published_date, :birth_date, :death_date
child :publications do
  extends "publications/public"
end
# publications/public.rabl
attributes :title, :publication_date, :publisher
# publications/show.rabl
object @publication
extends "publications/public"