example.rb

Gluttonberg::PageDescription.add do
  page :home do
    home    true
    label   "Home Page"
    view    "home"
    layout  "default"
    
    section :main do
      label "Main"
      type  :rich_text
      
      config :option => 1
    end
  end
  
  page :redirect do
    label       "Redirect"
    description "An example of a redirect"
    redirect_to :url, Merb::Router.url(:custom_route)
    # redirect_to :page
    # redirect_to do
    #   user = User.first
    #   Merb::Router.resource(user)
    # end
  end
end

page_dsl.rb

module Gluttonberg
  class PageDescription
    @@_descriptions = {}
    @@_home_page    = nil
    
    attr_accessor :options
    
    def initialize(name)
      @options = {:name => name, :home => false, :behaviour => :default}
      @sections = []
      @@_descriptions[name] = self
    end
    
    %w(label view layout limit description).each do |opt|
      class_eval %{
        def #{opt}(opt_value)
          @options[:#{opt}] = opt_value
        end
      }
    end
    
    def self.add(&blk)
      class_eval(&blk)
    end
    
    def self.page(name, &blk)
      new(name).instance_eval(&blk)
    end
    
    def home(bool)
      if bool
        @@_home_page = self
        @options[:limit] = 1
      elsif @@_home_page == self
        @@_home_page = nil
        @options.delete(:limit)
      end
    end
    
    def section(name, &blk)
      new_section = Section.new(name)
      new_section.instance_eval(&blk)
      @sections << new_section
    end
    
    def redirect_to(type_or_blk, opt = nil)
      if type_or_blk.is_a? Proc
        @redirect_type  = :block
        @redirect_block = type_or_blk
      else
        @redirect_type    = type_or_blk
        @redirect_option  = opt if opt
      end
    end
    
    def redirect?
      !@redirect_type.nil?
    end
    
    def redirect_url(page, params)
      path = case @redirect_type
        when :block     then @redirect_block.call
        when :url       then @redirect_option
        when :page      then redirect_to_page(page, params)
        when :component then Merb::Router.url(@redirect_option)
      end
      Router.localized_url(path, params)
    end
    
    private
    
    def redirect_to_page(page, params)
      localization = PageLocalization.first(
        :fields   => [:path],
        :page_id  => page.redirect_target_id,
        :locale   => params[:locale],
        :dialect  => params[:dialect]
      )
      raise DataMapper::ObjectNotFoundError unless localization
      localization.path
    end
    
    class Section
      attr_accessor :options, :custom
      
      def initialize(name)
        @options = {:name => name, :limit => 1}
      end
      
      %w(type limit).each do |opt|
        class_eval %{
          def #{opt}(opt_value)
            @options[:#{opt}] = opt_value
          end
        }
      end
      
      def config(opts)
        @config ||= {}
        @config.merge!(opts)
      end
    end # Section
  end # PageDescription
end # Gluttonberg