split

# File lib/uri/rfc2396_parser.rb, line 120
    def split(uri)
      case uri
      when ''
        # null uri

      when @regexp[:ABS_URI]
        scheme, opaque, userinfo, host, port,
          registry, path, query, fragment = $~[1..-1]

        # URI-reference = [ absoluteURI | relativeURI ] [ "#" fragment ]

        # absoluteURI   = scheme ":" ( hier_part | opaque_part )
        # hier_part     = ( net_path | abs_path ) [ "?" query ]
        # opaque_part   = uric_no_slash *uric

        # abs_path      = "/"  path_segments
        # net_path      = "//" authority [ abs_path ]

        # authority     = server | reg_name
        # server        = [ [ userinfo "@" ] hostport ]

        if !scheme
          raise InvalidURIError,
            "bad URI(absolute but no scheme): #{uri}"
        end
        if !opaque && (!path && (!host && !registry))
          raise InvalidURIError,
            "bad URI(absolute but no path): #{uri}"
        end

      when @regexp[:REL_URI]
        scheme = nil
        opaque = nil

        userinfo, host, port, registry,
          rel_segment, abs_path, query, fragment = $~[1..-1]
        if rel_segment && abs_path
          path = rel_segment + abs_path
        elsif rel_segment
          path = rel_segment
        elsif abs_path
          path = abs_path
        end

        # URI-reference = [ absoluteURI | relativeURI ] [ "#" fragment ]

        # relativeURI   = ( net_path | abs_path | rel_path ) [ "?" query ]

        # net_path      = "//" authority [ abs_path ]
        # abs_path      = "/"  path_segments
        # rel_path      = rel_segment [ abs_path ]

        # authority     = server | reg_name
        # server        = [ [ userinfo "@" ] hostport ]

      else
        raise InvalidURIError, "bad URI(is not URI?): #{uri}"
      end

      path = '' if !path && !opaque # (see RFC2396 Section 5.2)
      ret = [
        scheme,
        userinfo, host, port,         # X
        registry,                     # X
        path,                         # Y
        opaque,                       # Y
        query,
        fragment
      ]
      return ret
    end