shallow_scope

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 1713
          def shallow_scope(path, options = {}) #:nodoc:
            scope = { :as   => @scope[:shallow_prefix],
                      :path => @scope[:shallow_path] }
            @scope = @scope.new scope

            scope(path, options) { yield }
          ensure
            @scope = @scope.parent
          end