-;;; 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, 2000-2016 Free Software Foundation, Inc.
-;; Maintainer: FSF
+;; Maintainer: emacs-devel@gnu.org
;; Keywords: processes, unix
;; Package: emacs
(defconst env--substitute-vars-regexp
"\\$\\(?:\\(?1:[[:alnum:]_]+\\)\\|{\\(?1:[^{}]+\\)}\\|\\$\\)")
-(defun substitute-env-vars (string &optional only-defined)
+(defun substitute-env-vars (string &optional when-undefined)
"Substitute environment variables referred to in STRING.
`$FOO' where FOO is an environment variable name means to substitute
the value of that variable. The variable name should be terminated
with a character not a letter, digit or underscore; otherwise, enclose
the entire variable name in braces. For instance, in `ab$cd-x',
`$cd' is treated as an environment variable.
-If ONLY-DEFINED is nil, references to undefined environment variables
-are replaced by the empty string; if it is non-nil, they are left unchanged.
+
+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 env--substitute-vars-regexp string start)
(cond ((match-beginning 1)
- (let ((value (getenv (match-string 1 string))))
- (if (and (null value) only-defined)
+ (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)
+ (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.