scope

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 323
        def scope(*args)
          options = args.extract_options!
          options = options.dup

          if name_prefix = options.delete(:name_prefix)
            options[:as] ||= name_prefix
            ActiveSupport::Deprecation.warn ":name_prefix was deprecated in the new router syntax. Use :as instead.", caller
          end

          options[:path] = args.first if args.first.is_a?(String)
          recover = {}

          options[:constraints] ||= {}
          unless options[:constraints].is_a?(Hash)
            block, options[:constraints] = options[:constraints], {}
          end

          scope_options.each do |option|
            if value = options.delete(option)
              recover[option] = @scope[option]
              @scope[option]  = send("merge_#{option}_scope", @scope[option], value)
            end
          end

          recover[:block] = @scope[:blocks]
          @scope[:blocks] = merge_blocks_scope(@scope[:blocks], block)

          recover[:options] = @scope[:options]
          @scope[:options]  = merge_options_scope(@scope[:options], options)

          yield
          self
        ensure
          scope_options.each do |option|
            @scope[option] = recover[option] if recover.has_key?(option)
          end

          @scope[:options] = recover[:options]
          @scope[:blocks]  = recover[:block]
        end