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186 lines
7.0 KiB
EmacsLisp
186 lines
7.0 KiB
EmacsLisp
;;; env.el --- functions to manipulate environment variables
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;; Copyright (C) 1991, 1994, 2000, 2001, 2002, 2003, 2004,
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;; 2005, 2006 Free Software Foundation, Inc.
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;; Maintainer: FSF
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;; Keywords: processes, unix
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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;; Boston, MA 02110-1301, USA.
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;;; Commentary:
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;; UNIX processes inherit a list of name-to-string associations from their
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;; parents called their `environment'; these are commonly used to control
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;; program options. This package permits you to set environment variables
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;; to be passed to any sub-process run under Emacs.
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;; Note that the environment string `process-environment' is not
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;; decoded, but the args of `setenv' and `getenv' are normally
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;; multibyte text and get coding conversion.
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;;; Code:
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;; History list for environment variable names.
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(defvar read-envvar-name-history nil)
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(defun read-envvar-name (prompt &optional mustmatch)
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"Read environment variable name, prompting with PROMPT.
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Optional second arg MUSTMATCH, if non-nil, means require existing envvar name.
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If it is also not t, RET does not exit if it does non-null completion."
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(completing-read prompt
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(mapcar (lambda (enventry)
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(list (if enable-multibyte-characters
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(decode-coding-string
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(substring enventry 0
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(string-match "=" enventry))
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locale-coding-system t)
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(substring enventry 0
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(string-match "=" enventry)))))
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process-environment)
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nil mustmatch nil 'read-envvar-name-history))
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;; History list for VALUE argument to setenv.
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(defvar setenv-history nil)
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(defun substitute-env-vars (string)
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"Substitute environment variables referred to in STRING.
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`$FOO' where FOO is an environment variable name means to substitute
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the value of that variable. The variable name should be terminated
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with a character not a letter, digit or underscore; otherwise, enclose
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the entire variable name in braces. For instance, in `ab$cd-x',
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`$cd' is treated as an environment variable.
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Use `$$' to insert a single dollar sign."
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(let ((start 0))
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(while (string-match
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(eval-when-compile
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(rx (or (and "$" (submatch (1+ (regexp "[[:alnum:]_]"))))
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(and "${" (submatch (minimal-match (0+ anything))) "}")
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"$$")))
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string start)
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(cond ((match-beginning 1)
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(let ((value (getenv (match-string 1 string))))
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(setq string (replace-match (or value "") t t string)
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start (+ (match-beginning 0) (length value)))))
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((match-beginning 2)
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(let ((value (getenv (match-string 2 string))))
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(setq string (replace-match (or value "") t t string)
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start (+ (match-beginning 0) (length value)))))
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(t
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(setq string (replace-match "$" t t string)
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start (+ (match-beginning 0) 1)))))
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string))
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;; Fixme: Should `process-environment' be recoded if LC_CTYPE &c is set?
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(defun setenv (variable &optional value substitute-env-vars)
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"Set the value of the environment variable named VARIABLE to VALUE.
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VARIABLE should be a string. VALUE is optional; if not provided or
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nil, the environment variable VARIABLE will be removed.
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Interactively, a prefix argument means to unset the variable.
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Interactively, the current value (if any) of the variable
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appears at the front of the history list when you type in the new value.
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Interactively, always replace environment variables in the new value.
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SUBSTITUTE-ENV-VARS, if non-nil, means to substitute environment
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variables in VALUE with `substitute-env-vars', which see.
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This is normally used only for interactive calls.
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The return value is the new value of VARIABLE, or nil if
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it was removed from the environment.
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This function works by modifying `process-environment'.
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As a special case, setting variable `TZ' calls `set-time-zone-rule' as
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a side-effect."
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(interactive
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(if current-prefix-arg
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(list (read-envvar-name "Clear environment variable: " 'exact) nil)
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(let* ((var (read-envvar-name "Set environment variable: " nil))
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(value (getenv var)))
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(when value
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(add-to-history 'setenv-history value))
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;; Here finally we specify the args to give call setenv with.
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(list var
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(read-from-minibuffer (format "Set %s to value: " var)
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nil nil nil 'setenv-history
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value)
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t))))
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(if (and (multibyte-string-p variable) locale-coding-system)
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(let ((codings (find-coding-systems-string (concat variable value))))
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(unless (or (eq 'undecided (car codings))
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(memq (coding-system-base locale-coding-system) codings))
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(error "Can't encode `%s=%s' with `locale-coding-system'"
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variable (or value "")))))
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(and value
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substitute-env-vars
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(setq value (substitute-env-vars value)))
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(if (multibyte-string-p variable)
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(setq variable (encode-coding-string variable locale-coding-system)))
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(if (and value (multibyte-string-p value))
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(setq value (encode-coding-string value locale-coding-system)))
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(if (string-match "=" variable)
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(error "Environment variable name `%s' contains `='" variable)
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(let ((pattern (concat "\\`" (regexp-quote (concat variable "="))))
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(case-fold-search nil)
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(scan process-environment)
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found)
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(if (string-equal "TZ" variable)
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(set-time-zone-rule value))
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(while scan
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(cond ((string-match pattern (car scan))
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(setq found t)
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(if (eq nil value)
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(setq process-environment (delq (car scan)
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process-environment))
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(setcar scan (concat variable "=" value)))
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(setq scan nil)))
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(setq scan (cdr scan)))
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(or found
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(if value
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(setq process-environment
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(cons (concat variable "=" value)
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process-environment))))))
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value)
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(defun getenv (variable)
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"Get the value of environment variable VARIABLE.
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VARIABLE should be a string. Value is nil if VARIABLE is undefined in
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the environment. Otherwise, value is a string.
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This function consults the variable `process-environment'
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for its value."
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(interactive (list (read-envvar-name "Get environment variable: " t)))
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(let ((value (getenv-internal (if (multibyte-string-p variable)
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(encode-coding-string
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variable locale-coding-system)
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variable))))
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(if (and enable-multibyte-characters value)
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(setq value (decode-coding-string value locale-coding-system)))
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(when (interactive-p)
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(message "%s" (if value value "Not set")))
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value))
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(provide 'env)
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;;; arch-tag: b7d6a8f7-bc81-46db-8e39-8d721d4ed0b8
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;;; env.el ends here
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