lisp/eshell/em-basic.el

   1 ;;; em-basic.el --- basic shell builtin commands
   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-basic)
  25
  26 (eval-when-compile (require 'esh-maint))
  27
  28 (defgroup eshell-basic nil
  29   "The \"basic\" code provides a set of convenience functions which
  30 are traditionally considered shell builtins.  Since all of the
  31 functionality provided by them is accessible through Lisp, they are
  32 not really builtins at all, but offer a command-oriented way to do the
  33 same thing."
  34   :tag "Basic shell commands"
  35   :group 'eshell-module)
  36
  37 ;;; Commentary:
  38
  39 ;; There are very few basic Eshell commands -- so-called builtins.
  40 ;; They are: echo, umask, and version.
  41 ;;
  42 ;;;_* `echo'
  43 ;;
  44 ;; The `echo' command repeats its arguments to the screen.  It is
  45 ;; optional whether this is done in a Lisp-friendly fashion (so that
  46 ;; the value of echo is useful to a Lisp command using the result of
  47 ;; echo as an argument), or whether it should try to act like a normal
  48 ;; shell echo, and always result in a flat string being returned.
  49
  50 (defcustom eshell-plain-echo-behavior nil
  51   "*If non-nil, `echo' tries to behave like an ordinary shell echo.
  52 This comes at some detriment to Lisp functionality.  However, the Lisp
  53 equivalent of `echo' can always be achieved by using `identity'."
  54   :type 'boolean
  55   :group 'eshell-basic)
  56
  57 ;;;
  58 ;; An example of the difference is the following:
  59 ;;
  60 ;;   echo Hello world
  61 ;;
  62 ;; If `eshell-plain-echo-behavior' is non-nil, this will yield the
  63 ;; string "Hello world".  If Lisp behavior is enabled, however, it
  64 ;; will yield a list whose two elements are the strings "Hello" and
  65 ;; "world".  The way to write an equivalent expression for both would
  66 ;; be:
  67 ;;
  68 ;;   echo "Hello world"
  69 ;;
  70 ;; This always returns a single string.
  71 ;;
  72 ;;;_* `umask'
  73 ;;
  74 ;; The umask command changes the default file permissions for newly
  75 ;; created files.  It uses the same syntax as bash.
  76 ;;
  77 ;;;_* `version'
  78 ;;
  79 ;; This command reports the version number for Eshell and all its
  80 ;; dependent module, including the date when those modules were last
  81 ;; modified.
  82
  83 ;;; Code:
  84
  85 (require 'esh-opt)
  86
  87 ;;; Functions:
  88
  89 (defun eshell-echo (args &optional output-newline)
  90   "Implementation code for a Lisp version of `echo'.
  91 It returns a formatted value that should be passed to `eshell-print'
  92 or `eshell-printn' for display."
  93   (if eshell-plain-echo-behavior
  94       (concat (apply 'eshell-flatten-and-stringify args) "\n")
  95     (let ((value
  96            (cond
  97             ((= (length args) 0) "")
  98             ((= (length args) 1)
  99              (car args))
 100             (t
 101              (mapcar
 102               (function
 103                (lambda (arg)
 104                  (if (stringp arg)
 105                      (set-text-properties 0 (length arg) nil arg))
 106                  arg))
 107               args)))))
 108       (if output-newline
 109           (cond
 110            ((stringp value)
 111             (concat value "\n"))
 112            ((listp value)
 113             (append value (list "\n")))
 114            (t
 115             (concat (eshell-stringify value) "\n")))
 116         value))))
 117
 118 (defun eshell/echo (&rest args)
 119   "Implementation of `echo'.  See `eshell-plain-echo-behavior'."
 120   (eshell-eval-using-options
 121    "echo" args
 122    '((?n nil nil output-newline "terminate with a newline")
 123      (?h "help" nil nil "output this help screen")
 124      :preserve-args
 125      :usage "[-n] [object]")
 126    (eshell-echo args output-newline)))
 127
 128 (defun eshell/printnl (&rest args)
 129   "Print out each of the argument, separated by newlines."
 130   (let ((elems (eshell-flatten-list args)))
 131     (while elems
 132       (eshell-printn (eshell-echo (list (car elems))))
 133       (setq elems (cdr elems)))))
 134
 135 (defun eshell/listify (&rest args)
 136   "Return the argument(s) as a single list."
 137   (if (> (length args) 1)
 138       args
 139     (if (listp (car args))
 140         (car args)
 141       (list (car args)))))
 142
 143 (defun eshell/umask (&rest args)
 144   "Shell-like implementation of `umask'."
 145   (eshell-eval-using-options
 146    "umask" args
 147    '((?S "symbolic" nil symbolic-p "display umask symbolically")
 148      (?h "help" nil nil  "display this usage message")
 149      :usage "[-S] [mode]")
 150    (if (or (not args) symbolic-p)
 151        (let ((modstr
 152               (concat "000"
 153                       (format "%o"
 154                               (logand (lognot (default-file-modes))
 155                                       511)))))
 156          (setq modstr (substring modstr (- (length modstr) 3)))
 157          (when symbolic-p
 158            (let ((mode (default-file-modes)))
 159              (setq modstr
 160                    (format
 161                     "u=%s,g=%s,o=%s"
 162                     (concat (and (= (logand mode 64) 64) "r")
 163                             (and (= (logand mode 128) 128) "w")
 164                             (and (= (logand mode 256) 256) "x"))
 165                     (concat (and (= (logand mode 8) 8) "r")
 166                             (and (= (logand mode 16) 16) "w")
 167                             (and (= (logand mode 32) 32) "x"))
 168                     (concat (and (= (logand mode 1) 1) "r")
 169                             (and (= (logand mode 2) 2) "w")
 170                             (and (= (logand mode 4) 4) "x"))))))
 171          (eshell-printn modstr))
 172      (setcar args (eshell-convert (car args)))
 173      (if (numberp (car args))
 174          (set-default-file-modes
 175           (- 511 (car (read-from-string
 176                        (concat "?\\" (number-to-string (car args)))))))
 177        (error "setting umask symbolically is not yet implemented"))
 178      (eshell-print
 179       "Warning: umask changed for all new files created by Emacs.\n"))
 180    nil))
 181
 182 (eval-when-compile
 183   (defvar print-func))
 184
 185 ;;; arch-tag: 385a31b1-cb95-46f0-9829-9d352ee77db8
 186 ;;; em-basic.el ends here