get_to_from_path

# File actionpack/lib/action_dispatch/routing/mapper.rb, line 1645
        def get_to_from_path(path, to, action)
          return to if to || action

          path_without_format = path.sub(/\(\.:format\)$/, '')
          if using_match_shorthand?(path_without_format)
            path_without_format.gsub(%{^/}, "").sub(%{/([^/]*)$}, '#\1').tr("-", "_")
          else
            nil
          end
        end