| 1 | ;;; env.el --- functions to manipulate environment variables. |
| 2 | |
| 3 | ;; Copyright (C) 1991, 1994 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Maintainer: FSF |
| 6 | ;; Keywords: processes, unix |
| 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 2, or (at your option) |
| 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 the |
| 22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 23 | ;; Boston, MA 02111-1307, USA. |
| 24 | |
| 25 | ;;; Commentary: |
| 26 | |
| 27 | ;; UNIX processes inherit a list of name-to-string associations from their |
| 28 | ;; parents called their `environment'; these are commonly used to control |
| 29 | ;; program options. This package permits you to set environment variables |
| 30 | ;; to be passed to any sub-process run under Emacs. |
| 31 | |
| 32 | ;;; Code: |
| 33 | |
| 34 | ;; History list for environment variable names. |
| 35 | (defvar read-envvar-name-history nil) |
| 36 | |
| 37 | (defun read-envvar-name (prompt &optional mustmatch) |
| 38 | "Read environment variable name, prompting with PROMPT. |
| 39 | Optional second arg MUSTMATCH, if non-nil, means require existing envvar name. |
| 40 | If it is also not t, RET does not exit if it does non-null completion." |
| 41 | (completing-read prompt |
| 42 | (mapcar (function |
| 43 | (lambda (enventry) |
| 44 | (list (substring enventry 0 |
| 45 | (string-match "=" enventry))))) |
| 46 | process-environment) |
| 47 | nil mustmatch nil 'read-envvar-name-history)) |
| 48 | |
| 49 | ;; History list for VALUE argument to setenv. |
| 50 | (defvar setenv-history nil) |
| 51 | |
| 52 | ;;;###autoload |
| 53 | (defun setenv (variable &optional value unset) |
| 54 | "Set the value of the environment variable named VARIABLE to VALUE. |
| 55 | VARIABLE should be a string. VALUE is optional; if not provided or is |
| 56 | `nil', the environment variable VARIABLE will be removed. |
| 57 | |
| 58 | Interactively, a prefix argument means to unset the variable. |
| 59 | Interactively, the current value (if any) of the variable |
| 60 | appears at the front of the history list when you type in the new value. |
| 61 | |
| 62 | This function works by modifying `process-environment'." |
| 63 | (interactive |
| 64 | (if current-prefix-arg |
| 65 | (list (read-envvar-name "Clear environment variable: " 'exact) nil t) |
| 66 | (let ((var (read-envvar-name "Set environment variable: " nil))) |
| 67 | ;; Here finally we specify the args to give call setenv with. |
| 68 | (list var (read-from-minibuffer (format "Set %s to value: " var) |
| 69 | nil nil nil 'setenv-history |
| 70 | (getenv var)))))) |
| 71 | (if unset (setq value nil)) |
| 72 | (if (string-match "=" variable) |
| 73 | (error "Environment variable name `%s' contains `='" variable) |
| 74 | (let ((pattern (concat "\\`" (regexp-quote (concat variable "=")))) |
| 75 | (case-fold-search nil) |
| 76 | (scan process-environment) |
| 77 | found) |
| 78 | (if (string-equal "TZ" variable) |
| 79 | (set-time-zone-rule value)) |
| 80 | (while scan |
| 81 | (cond ((string-match pattern (car scan)) |
| 82 | (setq found t) |
| 83 | (if (eq nil value) |
| 84 | (setq process-environment (delq (car scan) process-environment)) |
| 85 | (setcar scan (concat variable "=" value))) |
| 86 | (setq scan nil))) |
| 87 | (setq scan (cdr scan))) |
| 88 | (or found |
| 89 | (if value |
| 90 | (setq process-environment |
| 91 | (cons (concat variable "=" value) |
| 92 | process-environment))))))) |
| 93 | |
| 94 | (provide 'env) |
| 95 | |
| 96 | ;;; env.el ends here |