A Gopher URL takes the form:
where <gopher-path> is one of
<gophertype><selector> <gophertype><selector>%09<search> <gophertype><selector>%09<search>%09<gopher+_string>
If :<port> is omitted, the port defaults to 70. <gophertype> is a single-character field to denote the Gopher type of the resource to which the URL refers. The entire <gopher-path> may also be empty, in which case the delimiting "/" is also optional and the <gophertype> defaults to "1".
<selector> is the Gopher selector string. In the Gopher protocol, Gopher selector strings are a sequence of octets which may contain any octets except 09 hexadecimal (US-ASCII HT or tab) 0A hexadecimal (US-ASCII character LF), and 0D (US-ASCII character CR).
Gopher clients specify which item to retrieve by sending the Gopher selector string to a Gopher server.
Within the <gopher-path>, no characters are reserved.
Note that some Gopher <selector> strings begin with a copy of the <gophertype> character, in which case that character will occur twice consecutively. The Gopher selector string may be an empty string; this is how Gopher clients refer to the top-level directory on a Gopher server.