diff options
Diffstat (limited to 'lisp/env.el')
| -rw-r--r-- | lisp/env.el | 47 |
1 files changed, 44 insertions, 3 deletions
diff --git a/lisp/env.el b/lisp/env.el index e0eebae61cc..b285da4847b 100644 --- a/lisp/env.el +++ b/lisp/env.el @@ -30,6 +30,23 @@ ;;; 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." + (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 unset) "Set the value of the environment variable named VARIABLE to VALUE. @@ -37,12 +54,36 @@ 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: " t) nil t) + (let* ((var (read-envvar-name "Set environment variable: " nil)) + (oldval (getenv var)) + newval + oldhist) + ;; Don't put the current value on the history + ;; if it is already there. + (if (equal oldval (car setenv-history)) + (setq oldval nil)) + ;; Now if OLDVAL is non-nil, we should add it to the history. + (if oldval + (setq setenv-history (cons oldval setenv-history))) + (setq oldhist setenv-history) + (setq newval (read-from-minibuffer (format "Set %s to value: " var) + nil nil nil 'setenv-history)) + ;; If we added the current value to the history, remove it. + ;; Note that read-from-minibuffer may have added the new value. + ;; Don't remove that! + (if oldval + (if (eq oldhist setenv-history) + (setq setenv-history (cdr setenv-history)) + (setcdr setenv-history (cdr (cdr setenv-history))))) + ;; Here finally we specify the args to give call setenv with. + (list var newval)))) (if unset (setq value nil)) (if (string-match "=" variable) (error "Environment variable name `%s' contains `='" variable) |