Regexp::Common::URI::gopher -- Returns a pattern for gopher URIs.

       Damian Conway (damian@conway.org)

       Bound to be plenty.

$RE{URI}{gopher}{-notab}
       Gopher URIs are poorly defined. Originally, RFC 1738 defined gopher URIs, but they were later redefined
       in an internet draft. One that was expired in June 1997.

       The internet draft for gopher URIs defines them as follows:

           "gopher:" "//" host [ ":" port ] "/" gopher-type selector
                               [ "%09" search [ "%09" gopherplus_string ]]

       Unfortunally, a selector is defined in such a way that characters may be escaped using the URI escape
       mechanism. This includes tabs, which escaped are %09. Hence, the syntax cannot distinguish between a URI
       that has both a selector and a search part, and an URI where the selector includes an escaped tab. (The
       text of the draft forbids tabs to be present in the selector though).

       "$RE{URI}{gopher}" follows the defined syntax. To disallow escaped tabs in the selector and search parts,
       use "$RE{URI}{gopher}{-notab}".

       There are other differences between the text and the given syntax.  According to the text, selector
       strings cannot have tabs, linefeeds or carriage returns in them. The text also allows the entire gopher-path, (the part after the slash following the hostport) to be empty; if this is empty the slash may be
       omitted as well. However, this isn't reflected in the syntax.

       Under "{-keep}", the following are returned:

       $1  The entire URI.

       $2  The scheme.

       $3  The host (name or address).

       $4  The port (if any).

       $5  The "gopher-path", the part after the / following the host and port.

       $6  The gopher-type.

       $7  The  selector. (When no "{-notab}" is used, this includes the search and gopherplus_string, including
           the separating escaped tabs).

       $8  The search, if given. (Only when "{-notab}" is given).

       $9  The gopherplus_string, if given. (Only when "{-notab}" is given).

       head1 REFERENCES

       [RFC1738]
           Berners-Lee, Tim, Masinter, L., McCahill, M.: UniformResourceLocators(URL). December 1994.

       [RFC1808]
           Fielding, R.: RelativeUniformResourceLocators(URL). June 1995.

       [GOPHERURL]
           Krishnan, Murali R., Casey, James: "A Gopher URL Format". Expired  Internet  draft  draft-murali-url-gopher. December 1996.

       This software is Copyright (c) 2001 - 2024, Damian Conway and Abigail.

       This module is free software, and maybe used under any of the following licenses:

        1) The Perl Artistic License.     See the file COPYRIGHT.AL.
        2) The Perl Artistic License 2.0. See the file COPYRIGHT.AL2.
        3) The BSD License.               See the file COPYRIGHT.BSD.
        4) The MIT License.               See the file COPYRIGHT.MIT.

perl v5.38.2                                       2024-08-10                   Regexp::Common::URI::gopher(3pm)

       This package is maintained by Abigail (regexp-common@abigail.freedom.nl).

       Regexp::Common::URI::gopher -- Returns a pattern for gopher URIs.

       Regexp::Common::URI for other supported URIs.

           use Regexp::Common qw /URI/;

           while (<>) {
               /$RE{URI}{gopher}/       and  print "Contains a gopher URI.\n";
           }