Commit cbfe666b authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

(setenv): Rewrite. Provide a way to unset interactively.

parent dad146f9
......@@ -31,30 +31,38 @@
;;; Code:
(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.
This function works by modifying `process-environment'."
(interactive "sSet environment variable: \nsSet %s to value: ")
(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))))))
(if unset (setq value nil))
(if (string-match "=" variable)
(error "Environment variable name `%s' contains `='" variable)
(let ((pattern (concat "\\`" (regexp-quote (concat variable "="))))
(case-fold-search nil)
(scan process-environment))
(if scan
(scan process-environment)
(while scan
((string-match pattern (car scan))
(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))
((null (setq scan (cdr scan)))
(setq process-environment
(cons (concat variable "=" value) process-environment)))))
(setq scan nil)))
(setq scan (cdr scan)))
(or found
(if value
(setq process-environment
(cons (concat variable "=" value) process-environment))))))
(cons (concat variable "=" value)
(provide 'env)
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