app

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 293
          def app(blocks)
            if to.is_a?(Class) && to < ActionController::Metal
              Routing::RouteSet::StaticDispatcher.new to
            else
              if to.respond_to?(:call)
                Constraints.new(to, blocks, Constraints::CALL)
              elsif blocks.any?
                Constraints.new(dispatcher(defaults.key?(:controller)), blocks, Constraints::SERVE)
              else
                dispatcher(defaults.key?(:controller))
              end
            end
          end