lisp/eshell/em-banner.el

   1 ;;; em-banner.el --- sample module that displays a login banner
   2
   3 ;; Copyright (C) 1999, 2000 Free Software Foundation
   4
   5 ;; Author: John Wiegley <johnw@gnu.org>
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22 ;; Boston, MA 02111-1307, USA.
  23
  24 (provide 'em-banner)
  25
  26 (eval-when-compile (require 'esh-maint))
  27
  28 (defgroup eshell-banner nil
  29   "This sample module displays a welcome banner at login.
  30 It exists so that others wishing to create their own Eshell extension
  31 modules may have a simple template to begin with."
  32   :tag "Login banner"
  33   :link '(info-link "(eshell)Login banner")
  34   :group 'eshell-module)
  35
  36 ;;; Commentary:
  37
  38 ;; There is nothing to be done or configured in order to use this
  39 ;; module, other than to select it by customizing the variable
  40 ;; `eshell-modules-list'.  It will then display a version information
  41 ;; message whenever Eshell is loaded.
  42 ;;
  43 ;; This code is only an example of a how to write a well-formed
  44 ;; extension module for Eshell.  The better way to display login text
  45 ;; is to use the `eshell-script' module, and to echo the desired
  46 ;; strings from the user's `eshell-login-script' file.
  47 ;;
  48 ;; There is one configuration variable, which demonstrates how to
  49 ;; properly define a customization variable in an extension module.
  50 ;; In this case, it allows the user to change the string which
  51 ;; displays at login time.
  52
  53 ;;; User Variables:
  54
  55 (defcustom eshell-banner-message "Welcome to the Emacs shell\n\n"
  56   "*The banner message to be displayed when Eshell is loaded.
  57 This can be any sexp, and should end with at least two newlines."
  58   :type 'sexp
  59   :group 'eshell-banner)
  60
  61 (put 'eshell-banner-message 'risky-local-variable t)
  62
  63 ;;; Code:
  64
  65 (require 'esh-util)
  66
  67 (defcustom eshell-banner-load-hook '(eshell-banner-initialize)
  68   "*A list of functions to run when `eshell-banner' is loaded."
  69   :type 'hook
  70   :group 'eshell-banner)
  71
  72 (defun eshell-banner-initialize ()
  73   "Output a welcome banner on initialization."
  74   ;; it's important to use `eshell-interactive-print' rather than
  75   ;; `insert', because `insert' doesn't know how to interact with the
  76   ;; I/O code used by Eshell
  77   (unless eshell-non-interactive-p
  78     (assert eshell-mode)
  79     (assert eshell-banner-message)
  80     (let ((msg (eval eshell-banner-message)))
  81       (assert msg)
  82       (eshell-interactive-print msg))))
  83
  84 (eshell-deftest banner banner-displayed
  85   "Startup banner is displayed at point-min"
  86   (assert eshell-banner-message)
  87   (let ((msg (eval eshell-banner-message)))
  88     (assert msg)
  89     (goto-char (point-min))
  90     (looking-at msg)))
  91
  92 ;;; em-banner.el ends here