(telnet): Add optional port arg.

lisp/net/telnet.el

@@ -197,18 +197,28 @@ rejecting one login and prompting again for a username and password.")
 ;;;###autoload (add-hook 'same-window-regexps "\\*telnet-.*\\*\\(\\|<[0-9]+>\\)")
 
 ;;;###autoload
-(defun telnet (host)
+(defun telnet (host &optional port)
   "Open a network login connection to host named HOST (a string).
+Optional arg PORT specifies alternative port to connect to.
+Interactively, use \\[universal-argument] prefix to be prompted for port number.
+
 Communication with HOST is recorded in a buffer `*PROGRAM-HOST*'
 where PROGRAM is the telnet program being used.  This program
 is controlled by the contents of the global variable `telnet-host-properties',
 falling back on the value of the global variable `telnet-program'.
 Normally input is edited in Emacs and sent a line at a time."
-  (interactive "sOpen connection to host: ")
+  (interactive (list (read-string "Open connection to host: ")
+		     (cond
+		      ((null current-prefix-arg) nil)
+		      ((consp current-prefix-arg) (read-string "Port: "))
+		      (t (prefix-numeric-value current-prefix-arg)))))
+  (if (and port (numberp port))
+      (setq port (int-to-string port)))
   (let* ((comint-delimiter-argument-list '(?\  ?\t))
 	 (properties (cdr (assoc host telnet-host-properties)))
 	 (telnet-program (if properties (car properties) telnet-program))
-         (name (concat telnet-program "-" (comint-arguments host 0 nil) ))
+	 (hname (if port (concat host ":" port) host))
+         (name (concat telnet-program "-" (comint-arguments hname 0 nil) ))
 	 (buffer (get-buffer (concat "*" name "*")))
 	 (telnet-options (if (cdr properties) (cons "-l" (cdr properties))))
 	 process)
@@ -221,7 +231,9 @@ Normally input is edited in Emacs and sent a line at a time."
       ;; Don't send the `open' cmd till telnet is ready for it.
       (accept-process-output process)
       (erase-buffer)
-      (send-string process (concat "open " host "\n"))
+      (send-string process (concat "open " host
+				   (if port " " "") (or port "")
+				   "\n"))
       (telnet-mode)
       (setq comint-input-sender 'telnet-simple-send)
       (setq telnet-count telnet-initial-count))))