-;;; env.el --- functions to manipulate environment variables
+;;; env.el --- functions to manipulate environment variables -*- lexical-binding:t -*-
-;; Copyright (C) 1991, 1994, 2000-2012 Free Software Foundation, Inc.
+;; Copyright (C) 1991, 1994, 2000-2014 Free Software Foundation, Inc.
-;; Maintainer: FSF
+;; Maintainer: emacs-devel@gnu.org
;; Keywords: processes, unix
;; Package: emacs
;;; Code:
-(eval-when-compile (require 'cl))
-
;; History list for environment variable names.
(defvar read-envvar-name-history nil)
;; History list for VALUE argument to setenv.
(defvar setenv-history nil)
+(defconst env--substitute-vars-regexp
+ "\\$\\(?:\\(?1:[[:alnum:]_]+\\)\\|{\\(?1:[^{}]+\\)}\\|\\$\\)")
-(defun substitute-env-vars (string)
+(defun substitute-env-vars (string &optional when-undefined)
"Substitute environment variables referred to in STRING.
`$FOO' where FOO is an environment variable name means to substitute
the value of that variable. The variable name should be terminated
the entire variable name in braces. For instance, in `ab$cd-x',
`$cd' is treated as an environment variable.
+If WHEN-DEFINED is nil, references to undefined environment variables
+are replaced by the empty string; if it is a function, the function is called
+with the variable name as argument and should return the text with which
+to replace it or nil to leave it unchanged.
+If it is non-nil and not a function, references to undefined variables are
+left unchanged.
+
Use `$$' to insert a single dollar sign."
(let ((start 0))
- (while (string-match
- (eval-when-compile
- (rx (or (and "$" (submatch (1+ (regexp "[[:alnum:]_]"))))
- (and "${" (submatch (minimal-match (0+ anything))) "}")
- "$$")))
- string start)
+ (while (string-match env--substitute-vars-regexp string start)
(cond ((match-beginning 1)
- (let ((value (getenv (match-string 1 string))))
- (setq string (replace-match (or value "") t t string)
- start (+ (match-beginning 0) (length value)))))
- ((match-beginning 2)
- (let ((value (getenv (match-string 2 string))))
- (setq string (replace-match (or value "") t t string)
- start (+ (match-beginning 0) (length value)))))
+ (let* ((var (match-string 1 string))
+ (value (getenv var)))
+ (if (and (null value)
+ (if (functionp when-undefined)
+ (null (setq value (funcall when-undefined var)))
+ when-undefined))
+ (setq start (match-end 0))
+ (setq string (replace-match (or value "") t t string)
+ start (+ (match-beginning 0) (length value))))))
(t
(setq string (replace-match "$" t t string)
start (+ (match-beginning 0) 1)))))
string))
+(defun substitute-env-in-file-name (filename)
+ (substitute-env-vars filename
+ ;; How 'bout we lookup other tables than the env?
+ ;; E.g. we could accept bookmark names as well!
+ (if (memq system-type '(windows-nt ms-dos))
+ (lambda (var) (getenv (upcase var)))
+ t)))
(defun setenv-internal (env variable value keep-empty)
"Set VARIABLE to VALUE in ENV, adding empty entries if KEEP-EMPTY.
the environment. Otherwise, value is a string.
If optional parameter FRAME is non-nil, then it should be a
-frame. This function will look up VARIABLE in its 'environment
+frame. This function will look up VARIABLE in its `environment'
parameter.
Otherwise, this function searches `process-environment' for