lisp/talk.el

   1 ;;; talk.el --- allow several users to talk to each other through Emacs
   2
   3 ;; Copyright (C) 1995, 2001-2012 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: comm, frames
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; This is a multi-user talk package that runs in Emacs.
  26 ;; Use talk-connect to bring a new person into the conversation.
  27
  28 ;;; Code:
  29
  30 (defvar talk-display-alist nil
  31   "Alist of displays on which Emacs talk is now running.
  32 Each element has the form (DISPLAY FRAME BUFFER).")
  33
  34 ;;;###autoload
  35 (defun talk-connect (display)
  36   "Connect to display DISPLAY for the Emacs talk group."
  37   (interactive "sTalk to display: ")
  38   ;; Make sure we have an entry for the current display.
  39   (let ((mydisp (cdr (assq 'display (frame-parameters (selected-frame))))))
  40     (talk-add-display mydisp))
  41   ;; Make sure we have an entry for the specified display.
  42   (talk-add-display display)
  43   ;; Add the new buffers to all talk frames.
  44   (talk-update-buffers))
  45
  46 ;;;###autoload
  47 (defun talk ()
  48   "Connect to the Emacs talk group from the current X display or tty frame."
  49   (interactive)
  50   (let ((type (frame-live-p (selected-frame))))
  51     (if (or (eq type t) (eq type 'x))
  52         (talk-add-display
  53          (terminal-name (frame-terminal (selected-frame))))
  54       (error "Unknown frame type")))
  55   (talk-update-buffers))
  56
  57 (defun talk-add-display (display)
  58   (let* ((elt (assoc display talk-display-alist))
  59          (name (concat "*talk-" display "*"))
  60          frame buffer)
  61     (if (and elt (frame-live-p (nth 1 elt)))
  62         (setq frame (nth 1 elt))
  63       (setq frame (make-frame-on-display display (list (cons 'name name)))))
  64     (if (not (and elt (buffer-name (get-buffer (setq buffer (nth 2 elt))))))
  65         (setq buffer (get-buffer-create name)))
  66     (add-to-list 'delete-frame-functions 'talk-handle-delete-frame)
  67     (setq talk-display-alist
  68           (cons (list display frame buffer) (delq elt talk-display-alist)))))
  69
  70 (defun talk-handle-delete-frame (frame)
  71   (dolist (d talk-display-alist)
  72     (when (eq (nth 1 d) frame)
  73       (setq talk-display-alist (delq d talk-display-alist))
  74       (talk-update-buffers))))
  75
  76 (defun talk-disconnect ()
  77   "Disconnect this display from the Emacs talk group."
  78   (interactive)
  79   (let* ((mydisp (cdr (assq 'display (frame-parameters (selected-frame)))))
  80          (elt (assoc mydisp talk-display-alist)))
  81     (delete-frame (nth 1 elt))
  82     (kill-buffer (nth 2 elt))
  83     (setq talk-display-alist (delq elt talk-display-alist))
  84     (talk-update-buffers)))
  85
  86 (defun talk-update-buffers ()
  87   "Update all the talk frames so that each shows all the talk buffers."
  88   (let ((tail talk-display-alist))
  89     (while tail
  90       (let ((frame (nth 1 (car tail)))
  91             (this-buffer (nth 2 (car tail)))
  92             (buffers
  93              (mapcar (function (lambda (elt) (nth 2 elt)))
  94                      talk-display-alist)))
  95         ;; Put this display's own talk buffer
  96         ;; at the front of the list.
  97         (setq buffers (cons this-buffer (delq this-buffer buffers)))
  98         (talk-split-up-frame frame buffers))
  99       (setq tail (cdr tail)))))
 100
 101 (defun talk-split-up-frame (frame buffers)
 102   "Split FRAME into equal-sized windows displaying the buffers in BUFFERS.
 103 Select the first of these windows, displaying the first of the buffers."
 104   (let ((lines-per-buffer (/ (frame-height frame) (length buffers)))
 105         (old-frame (selected-frame)))
 106     (unwind-protect
 107         (progn
 108           (select-frame frame)
 109           (select-window (frame-first-window frame))
 110           (delete-other-windows)
 111           (while (progn
 112                    (switch-to-buffer (car buffers))
 113                    (setq buffers (cdr buffers)))
 114             (split-window-below lines-per-buffer)
 115             (other-window 1))
 116           (select-window (frame-first-window frame)))
 117       (select-frame old-frame))))
 118
 119 (provide 'talk)
 120
 121 ;;; talk.el ends here