Explain combine-and-quote-strings, split-string-and-unquote.
[emacs.git] / lisp / eshell / em-basic.el
blob458f6918de45f313990751b7347d3bc54c747456
1 ;;; em-basic.el --- basic shell builtin commands
3 ;; Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004,
4 ;; 2005, 2006, 2007 Free Software Foundation, Inc.
6 ;; Author: John Wiegley <johnw@gnu.org>
8 ;; This file is part of GNU Emacs.
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, or (at your option)
13 ;; any later version.
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.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to the
22 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
23 ;; Boston, MA 02110-1301, USA.
25 (provide 'em-basic)
27 (eval-when-compile (require 'esh-maint))
29 (defgroup eshell-basic nil
30 "The \"basic\" code provides a set of convenience functions which
31 are traditionally considered shell builtins. Since all of the
32 functionality provided by them is accessible through Lisp, they are
33 not really builtins at all, but offer a command-oriented way to do the
34 same thing."
35 :tag "Basic shell commands"
36 :group 'eshell-module)
38 ;;; Commentary:
40 ;; There are very few basic Eshell commands -- so-called builtins.
41 ;; They are: echo, umask, and version.
43 ;;;_* `echo'
45 ;; The `echo' command repeats its arguments to the screen. It is
46 ;; optional whether this is done in a Lisp-friendly fashion (so that
47 ;; the value of echo is useful to a Lisp command using the result of
48 ;; echo as an argument), or whether it should try to act like a normal
49 ;; shell echo, and always result in a flat string being returned.
51 (defcustom eshell-plain-echo-behavior nil
52 "*If non-nil, `echo' tries to behave like an ordinary shell echo.
53 This comes at some detriment to Lisp functionality. However, the Lisp
54 equivalent of `echo' can always be achieved by using `identity'."
55 :type 'boolean
56 :group 'eshell-basic)
58 ;;;
59 ;; An example of the difference is the following:
61 ;; echo Hello world
63 ;; If `eshell-plain-echo-behavior' is non-nil, this will yield the
64 ;; string "Hello world". If Lisp behavior is enabled, however, it
65 ;; will yield a list whose two elements are the strings "Hello" and
66 ;; "world". The way to write an equivalent expression for both would
67 ;; be:
69 ;; echo "Hello world"
71 ;; This always returns a single string.
73 ;;;_* `umask'
75 ;; The umask command changes the default file permissions for newly
76 ;; created files. It uses the same syntax as bash.
78 ;;;_* `version'
80 ;; This command reports the version number for Eshell and all its
81 ;; dependent module, including the date when those modules were last
82 ;; modified.
84 ;;; Code:
86 (require 'esh-opt)
88 ;;; Functions:
90 (defun eshell-echo (args &optional output-newline)
91 "Implementation code for a Lisp version of `echo'.
92 It returns a formatted value that should be passed to `eshell-print'
93 or `eshell-printn' for display."
94 (if eshell-plain-echo-behavior
95 (concat (apply 'eshell-flatten-and-stringify args) "\n")
96 (let ((value
97 (cond
98 ((= (length args) 0) "")
99 ((= (length args) 1)
100 (car args))
102 (mapcar
103 (function
104 (lambda (arg)
105 (if (stringp arg)
106 (set-text-properties 0 (length arg) nil arg))
107 arg))
108 args)))))
109 (if output-newline
110 (cond
111 ((stringp value)
112 (concat value "\n"))
113 ((listp value)
114 (append value (list "\n")))
116 (concat (eshell-stringify value) "\n")))
117 value))))
119 (defun eshell/echo (&rest args)
120 "Implementation of `echo'. See `eshell-plain-echo-behavior'."
121 (eshell-eval-using-options
122 "echo" args
123 '((?n nil nil output-newline "terminate with a newline")
124 (?h "help" nil nil "output this help screen")
125 :preserve-args
126 :usage "[-n] [object]")
127 (eshell-echo args output-newline)))
129 (defun eshell/printnl (&rest args)
130 "Print out each of the argument, separated by newlines."
131 (let ((elems (eshell-flatten-list args)))
132 (while elems
133 (eshell-printn (eshell-echo (list (car elems))))
134 (setq elems (cdr elems)))))
136 (defun eshell/listify (&rest args)
137 "Return the argument(s) as a single list."
138 (if (> (length args) 1)
139 args
140 (if (listp (car args))
141 (car args)
142 (list (car args)))))
144 (defun eshell/umask (&rest args)
145 "Shell-like implementation of `umask'."
146 (eshell-eval-using-options
147 "umask" args
148 '((?S "symbolic" nil symbolic-p "display umask symbolically")
149 (?h "help" nil nil "display this usage message")
150 :usage "[-S] [mode]")
151 (if (or (not args) symbolic-p)
152 (let ((modstr
153 (concat "000"
154 (format "%o"
155 (logand (lognot (default-file-modes))
156 511)))))
157 (setq modstr (substring modstr (- (length modstr) 3)))
158 (when symbolic-p
159 (let ((mode (default-file-modes)))
160 (setq modstr
161 (format
162 "u=%s,g=%s,o=%s"
163 (concat (and (= (logand mode 64) 64) "r")
164 (and (= (logand mode 128) 128) "w")
165 (and (= (logand mode 256) 256) "x"))
166 (concat (and (= (logand mode 8) 8) "r")
167 (and (= (logand mode 16) 16) "w")
168 (and (= (logand mode 32) 32) "x"))
169 (concat (and (= (logand mode 1) 1) "r")
170 (and (= (logand mode 2) 2) "w")
171 (and (= (logand mode 4) 4) "x"))))))
172 (eshell-printn modstr))
173 (setcar args (eshell-convert (car args)))
174 (if (numberp (car args))
175 (set-default-file-modes
176 (- 511 (car (read-from-string
177 (concat "?\\" (number-to-string (car args)))))))
178 (error "setting umask symbolically is not yet implemented"))
179 (eshell-print
180 "Warning: umask changed for all new files created by Emacs.\n"))
181 nil))
183 (eval-when-compile
184 (defvar print-func))
186 ;;; arch-tag: 385a31b1-cb95-46f0-9829-9d352ee77db8
187 ;;; em-basic.el ends here