(read_minibuf): Clean up the binding stack if

[bpt/emacs.git] / lisp / env.el

diff --git a/lisp/env.el b/lisp/env.el
index e0eebae..4981fe6 100644 (file)
--- a/lisp/env.el
+++ b/lisp/env.el
@@ -1,48 +1,72 @@
 ;;; env.el --- functions to manipulate environment variables.
 
-;;; Copyright 1991, 1994 Free Software Foundation, Inc.
+;; Copyright (C) 1991, 1994 Free Software Foundation, Inc.
 
 ;; Maintainer: FSF
 ;; Keywords: processes, unix
 
-;;; This file is part of GNU Emacs.
+;; This file is part of GNU Emacs.
 
-;;; GNU Emacs is free software; you can redistribute it and/or modify
-;;; it under the terms of the GNU General Public License as published by
-;;; the Free Software Foundation; either version 2, or (at your option)
-;;; any later version.
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
 
-;;; GNU Emacs is distributed in the hope that it will be useful,
-;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-;;; GNU General Public License for more details.
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
 
-;;; You should have received a copy of the GNU General Public License
-;;; along with GNU Emacs; see the file COPYING.  If not, write to
-;;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
 
 ;;; Commentary:
 
-;; UNIX processes inherit a list of name-to-string associations from
-;; their parents called their `environment'; these are commonly used
-;; to control program options.  This package permits you to set
-;; environment variables to be passed to any sub-process run under Emacs.
+;; UNIX processes inherit a list of name-to-string associations from their
+;; parents called their `environment'; these are commonly used to control
+;; program options.  This package permits you to set environment variables
+;; to be passed to any sub-process run under Emacs.
 
 ;;; Code:
 
-;;;###autoload
+;; History list for environment variable names.
+(defvar read-envvar-name-history nil)
+
+(defun read-envvar-name (prompt &optional mustmatch)
+  "Read environment variable name, prompting with PROMPT.
+Optional second arg MUSTMATCH, if non-nil, means require existing envvar name.
+If it is also not t, RET does not exit if it does non-null completion."
+  (completing-read prompt
+                  (mapcar (function
+                           (lambda (enventry)
+                             (list (substring enventry 0
+                                              (string-match "=" enventry)))))
+                          process-environment)
+                  nil mustmatch nil 'read-envvar-name-history))
+
+;; History list for VALUE argument to setenv.
+(defvar setenv-history nil)
+
 (defun setenv (variable &optional value unset)
   "Set the value of the environment variable named VARIABLE to VALUE.
 VARIABLE should be a string.  VALUE is optional; if not provided or is
 `nil', the environment variable VARIABLE will be removed.  
 
 Interactively, a prefix argument means to unset the variable.
+Interactively, the current value (if any) of the variable
+appears at the front of the history list when you type in the new value.
+
 This function works by modifying `process-environment'."
   (interactive
    (if current-prefix-arg
-       (list (read-string "Clear environment variable: ") nil t)
-     (let ((var (read-string "Set environment variable: ")))
-       (list var (read-string (format "Set %s to value: " var))))))
+       (list (read-envvar-name "Clear environment variable: " 'exact) nil t)
+     (let ((var (read-envvar-name "Set environment variable: " nil)))
+       ;; Here finally we specify the args to give call setenv with.
+       (list var (read-from-minibuffer (format "Set %s to value: " var)
+                                      nil nil nil 'setenv-history
+                                      (getenv var))))))
   (if unset (setq value nil))
   (if (string-match "=" variable)
       (error "Environment variable name `%s' contains `='" variable)
@@ -50,6 +74,8 @@ This function works by modifying `process-environment'."
          (case-fold-search nil)
          (scan process-environment)
          found)
+      (if (string-equal "TZ" variable)
+         (set-time-zone-rule value))
       (while scan
        (cond ((string-match pattern (car scan))
               (setq found t)
@@ -64,6 +90,19 @@ This function works by modifying `process-environment'."
                    (cons (concat variable "=" value)
                          process-environment)))))))
 
+(defun getenv (variable)
+  "Get the value of environment variable VARIABLE.
+VARIABLE should be a string.  Value is nil if VARIABLE is undefined in
+the environment.  Otherwise, value is a string.
+
+This function consults the variable `process-environment'
+for its value."
+  (interactive (list (read-envvar-name "Get environment variable: " t)))
+  (let ((value (getenv-internal variable)))
+    (when (interactive-p)
+      (message "%s" (if value value "Not set")))
+    value))
+
 (provide 'env)
 
 ;;; env.el ends here