    # File lib/merb-core/bootloader.rb, line 1323
      def self.run
        require 'rack'
        if File.exists?(Merb.dir_for(:config) / "rack.rb")
          Merb::Config[:rackup] ||= Merb.dir_for(:config) / "rack.rb"
        end

        if Merb::Config[:rackup]
          rackup_code = File.read(Merb::Config[:rackup])
          Merb::Config[:app] = eval("::Rack::Builder.new {( #{rackup_code}\n )}.to_app", TOPLEVEL_BINDING, Merb::Config[:rackup])
        else
          Merb::Config[:app] = ::Rack::Builder.new {
             use Merb::Rack::Head # handle head requests
             use Merb::Rack::ContentLength # report content length
             if prefix = ::Merb::Config[:path_prefix]
               use Merb::Rack::PathPrefix, prefix
             end
             use Merb::Rack::Static, Merb.dir_for(:public)
             run Merb::Rack::Application.new
           }.to_app
        end

        nil
      end