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1bbda2d6 | 1 | ;;; env.el --- functions to manipulate environment variables. |
c88ab9ce | 2 | |
dffc4996 | 3 | ;;; Copyright 1991, 1994 Free Software Foundation, Inc. |
971571b9 | 4 | |
e5167999 | 5 | ;; Maintainer: FSF |
d9ecc911 | 6 | ;; Keywords: processes, unix |
e5167999 | 7 | |
6449c898 JB |
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 | |
e5167999 | 12 | ;;; the Free Software Foundation; either version 2, or (at your option) |
6449c898 JB |
13 | ;;; 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; see the file COPYING. If not, write to | |
22 | ;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. | |
23 | ||
d9ecc911 ER |
24 | ;;; Commentary: |
25 | ||
26 | ;; UNIX processes inherit a list of name-to-string associations from | |
27 | ;; their parents called their `environment'; these are commonly used | |
28 | ;; to control program options. This package permits you to set | |
29 | ;; environment variables to be passed to any sub-process run under Emacs. | |
30 | ||
e5167999 ER |
31 | ;;; Code: |
32 | ||
99ac138a RS |
33 | ;; History list for environment variable names. |
34 | (defvar read-envvar-name-history nil) | |
35 | ||
36 | (defun read-envvar-name (prompt &optional mustmatch) | |
37 | "Read environment variable name, prompting with PROMPT. | |
38 | Optional second arg MUSTMATCH, if non-nil, means require existing envvar name." | |
39 | (completing-read prompt | |
40 | (mapcar (function | |
41 | (lambda (enventry) | |
42 | (list (substring enventry 0 | |
43 | (string-match "=" enventry))))) | |
44 | process-environment) | |
45 | nil mustmatch nil 'read-envvar-name-history)) | |
46 | ||
47 | ;; History list for VALUE argument to setenv. | |
48 | (defvar setenv-history nil) | |
49 | ||
aa673ecc | 50 | ;;;###autoload |
cbfe666b | 51 | (defun setenv (variable &optional value unset) |
6449c898 | 52 | "Set the value of the environment variable named VARIABLE to VALUE. |
1bbda2d6 NF |
53 | VARIABLE should be a string. VALUE is optional; if not provided or is |
54 | `nil', the environment variable VARIABLE will be removed. | |
cbfe666b RS |
55 | |
56 | Interactively, a prefix argument means to unset the variable. | |
99ac138a RS |
57 | Interactively, the current value (if any) of the variable |
58 | appears at the front of the history list when you type in the new value. | |
59 | ||
b6a5978e | 60 | This function works by modifying `process-environment'." |
cbfe666b RS |
61 | (interactive |
62 | (if current-prefix-arg | |
99ac138a RS |
63 | (list (read-envvar-name "Clear environment variable: " t) nil t) |
64 | (let* ((var (read-envvar-name "Set environment variable: " nil)) | |
65 | (oldval (getenv var)) | |
66 | newval | |
67 | oldhist) | |
68 | ;; Don't put the current value on the history | |
69 | ;; if it is already there. | |
70 | (if (equal oldval (car setenv-history)) | |
71 | (setq oldval nil)) | |
72 | ;; Now if OLDVAL is non-nil, we should add it to the history. | |
73 | (if oldval | |
74 | (setq setenv-history (cons oldval setenv-history))) | |
75 | (setq oldhist setenv-history) | |
76 | (setq newval (read-from-minibuffer (format "Set %s to value: " var) | |
77 | nil nil nil 'setenv-history)) | |
78 | ;; If we added the current value to the history, remove it. | |
79 | ;; Note that read-from-minibuffer may have added the new value. | |
80 | ;; Don't remove that! | |
81 | (if oldval | |
82 | (if (eq oldhist setenv-history) | |
83 | (setq setenv-history (cdr setenv-history)) | |
84 | (setcdr setenv-history (cdr (cdr setenv-history))))) | |
85 | ;; Here finally we specify the args to give call setenv with. | |
86 | (list var newval)))) | |
cbfe666b | 87 | (if unset (setq value nil)) |
6449c898 | 88 | (if (string-match "=" variable) |
1bbda2d6 | 89 | (error "Environment variable name `%s' contains `='" variable) |
971571b9 | 90 | (let ((pattern (concat "\\`" (regexp-quote (concat variable "=")))) |
7e68de56 | 91 | (case-fold-search nil) |
cbfe666b RS |
92 | (scan process-environment) |
93 | found) | |
94 | (while scan | |
95 | (cond ((string-match pattern (car scan)) | |
96 | (setq found t) | |
97 | (if (eq nil value) | |
98 | (setq process-environment (delq (car scan) process-environment)) | |
99 | (setcar scan (concat variable "=" value))) | |
100 | (setq scan nil))) | |
101 | (setq scan (cdr scan))) | |
102 | (or found | |
103 | (if value | |
a3cda273 | 104 | (setq process-environment |
cbfe666b RS |
105 | (cons (concat variable "=" value) |
106 | process-environment))))))) | |
49116ac0 | 107 | |
1bbda2d6 NF |
108 | (provide 'env) |
109 | ||
110 | ;;; env.el ends here |