def irc_eql?(first, second, casemapping = :rfc1459)
      return irc_upcase(first, casemapping) == irc_upcase(second, casemapping)
    end
def irc_eql?(first, second, casemapping = :rfc1459)
      return irc_upcase(first, casemapping) == irc_upcase(second, casemapping)
    end
Check an IRC identifier (nick, channel) for equality.
 @param [String] first The first IRC string to compare.
 @param [String] second The second IRC string to compare.
 @param [Symbol] casemapping The IRC casemappig to use for the comparison.
 @return [Boolean] Will be `true` if the strings only differ in case or
   not all, but `false` otherwise.