X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/b3b8e915784908ca28639e48158018dec9746de4..b2a577ecba1690db0f631f5fcf514685a7be06aa:/lisp/env.el

diff --git a/lisp/env.el b/lisp/env.el
index 256a3338e6..02e4e04b62 100644
--- a/lisp/env.el
+++ b/lisp/env.el
@@ -1,56 +1,95 @@
 ;;; env.el --- functions to manipulate environment variables.
 
-;;; Copyright Free Software Foundation 1991
+;; 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:
 
+;; 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)
+
 ;;;###autoload
-(defun setenv (variable &optional value)
+(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 "sSet environment variable: \nsSet %s to value: ")
+  (interactive
+   (if current-prefix-arg
+       (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)
     (let ((pattern (concat "\\`" (regexp-quote (concat variable "="))))
-	  (scan 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))
-          (if (eq nil value)
-              (setq process-environment (delq (car scan) process-environment))
-            (setcar scan (concat variable "=" value)))
-	  (setq scan nil))
-	 ((null (setq scan (cdr scan)))
-	  (setq process-environment
-		(cons (concat variable "=" value) process-environment))))))))
+	(cond ((string-match pattern (car scan))
+	       (setq found t)
+	       (if (eq nil value)
+		   (setq process-environment (delq (car scan) process-environment))
+		 (setcar scan (concat variable "=" value)))
+	       (setq scan nil)))
+	(setq scan (cdr scan)))
+      (or found
+	  (if value
+	      (setq process-environment
+		    (cons (concat variable "=" value)
+			  process-environment)))))))
 
 (provide 'env)