205 lines
8.3 KiB
EmacsLisp
205 lines
8.3 KiB
EmacsLisp
;;; minibuf-eldef.el --- Only show defaults in prompts when applicable -*- lexical-binding: t -*-
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;;
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;; Copyright (C) 2000-2024 Free Software Foundation, Inc.
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;;
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;; Author: Miles Bader <miles@gnu.org>
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;; Keywords: convenience
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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 3 of the License, or
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;; (at your option) 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. If not, see <https://www.gnu.org/licenses/>.
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;;; Commentary:
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;;
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;; Defines the mode `minibuffer-electric-default-mode'.
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;;
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;; When active, minibuffer prompts that show a default value only show
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;; the default when it's applicable -- that is, when hitting RET would
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;; yield the default value. If the user modifies the input such that
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;; hitting RET would enter a non-default value, the prompt is modified
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;; to remove the default indication (which is restored if the input is
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;; ever restore to the match the initial input).
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;;; Code:
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(defvar minibuffer-eldef-shorten-default)
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(defun minibuffer-default--in-prompt-regexps ()
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(cons
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(list
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(concat
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"\\("
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(if (string-match "%s" minibuffer-default-prompt-format)
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(concat
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(regexp-quote (substring minibuffer-default-prompt-format
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0 (match-beginning 0)))
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"\\(.*?\\)"
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(regexp-quote (substring minibuffer-default-prompt-format
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(match-end 0))))
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(regexp-quote minibuffer-default-prompt-format))
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"\\): ")
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1 (and minibuffer-eldef-shorten-default " [\\2]"))
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`(("\\( (default\\(?: is\\)? \\(.*\\))\\):? \\'"
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1 ,(if minibuffer-eldef-shorten-default " [\\2]"))
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("([^(]+?\\(, default\\(?: is\\)? \\(.*\\)\\)):? \\'" 1)
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("\\( \\[.*\\]\\):? *\\'" 1))))
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(defcustom minibuffer-eldef-shorten-default nil
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"If non-nil, shorten \"(default ...)\" to \"[...]\" in minibuffer prompts."
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:set (lambda (symbol value)
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(set-default symbol value)
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(setq-default minibuffer-default-in-prompt-regexps
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(minibuffer-default--in-prompt-regexps)))
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:type 'boolean
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:group 'minibuffer
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:version "24.3")
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(make-obsolete-variable 'minibuffer-eldef-shorten-default
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'minibuffer-default-prompt-format "29.1")
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(defvar minibuffer-default-in-prompt-regexps
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(minibuffer-default--in-prompt-regexps)
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"A list of regexps matching the parts of minibuffer prompts showing defaults.
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When `minibuffer-electric-default-mode' is active, these regexps are
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used to identify the portions of prompts to elide.
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Each entry is of the form (REGEXP MATCH-NUM &optional REWRITE),
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where REGEXP should match the default part of the prompt,
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MATCH-NUM is the subgroup that matched the actual default indicator,
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and REWRITE, if present, is a string to pass to `replace-match' that
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should be displayed in its place.")
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;;; Internal variables
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;; A list of minibuffers to which we've added a post-command-hook.
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(defvar minibuf-eldef-frobbed-minibufs nil)
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;;; The following are all local variables in the minibuffer
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;; Input pre-inserted into the minibuffer before the user can edit it.
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(defvar minibuf-eldef-initial-input)
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(make-variable-buffer-local 'minibuf-eldef-initial-input)
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;; and the length of the buffer with it inserted.
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(defvar minibuf-eldef-initial-buffer-length)
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(make-variable-buffer-local 'minibuf-eldef-initial-buffer-length)
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;; True if the current minibuffer prompt contains the default spec.
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(defvar minibuf-eldef-showing-default-in-prompt)
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(make-variable-buffer-local 'minibuf-eldef-showing-default-in-prompt)
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;; An overlay covering the default portion of the prompt
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(defvar minibuf-eldef-overlay)
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(make-variable-buffer-local 'minibuf-eldef-overlay)
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;;; Hook functions
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;; This function goes on minibuffer-setup-hook
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(defun minibuf-eldef-setup-minibuffer ()
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"Set up a minibuffer for `minibuffer-electric-default-mode'.
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The prompt and initial input should already have been inserted."
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(let ((regexps minibuffer-default-in-prompt-regexps)
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(match nil))
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(save-excursion
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(save-restriction
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;; Narrow to only the prompt.
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(goto-char (point-min))
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(narrow-to-region (point) (minibuffer-prompt-end))
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;; See if the prompt contains a default input indicator.
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(while regexps
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(setq match (pop regexps))
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(cond
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((not (re-search-forward (if (stringp match) match (car match))
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nil t))
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;; No match yet, try the next rule.
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(setq match nil))
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((and (consp (cdr-safe match)) (nth 2 match))
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;; Matched a replacement rule.
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(let* ((inhibit-read-only t)
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(buffer-undo-list t)
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(submatch (nth 1 match))
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(replacement (nth 2 match))
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(props (text-properties-at (match-beginning submatch))))
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(replace-match replacement nil nil nil submatch)
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(set-text-properties (match-beginning submatch)
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(match-end submatch)
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props)
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;; Replacement done, now keep trying with subsequent rules.
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(setq match nil)
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(goto-char (point-min))))
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;; Matched a non-replacement (i.e. electric hide) rule, no need to
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;; keep trying.
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(t (setq regexps nil))))))
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(if (not match)
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;; No match for electric hiding, so just make sure our
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;; post-command-hook isn't left around.
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(remove-hook 'post-command-hook #'minibuf-eldef-update-minibuffer t)
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;; Yup; set things up so we can frob the prompt as the state of
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;; the input string changes.
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(setq match (if (consp match) (cdr match) 0))
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(setq match (if (consp match) (car match) match))
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(setq minibuf-eldef-overlay
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(make-overlay (match-beginning match) (match-end match)))
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(setq minibuf-eldef-showing-default-in-prompt t)
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(setq minibuf-eldef-initial-input
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(minibuffer-contents-no-properties))
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(setq minibuf-eldef-initial-buffer-length (point-max))
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(add-to-list 'minibuf-eldef-frobbed-minibufs (current-buffer))
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(add-hook 'post-command-hook #'minibuf-eldef-update-minibuffer nil t))))
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;; post-command-hook to swap prompts when necessary
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(defun minibuf-eldef-update-minibuffer ()
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"Update a minibuffer's prompt to include a default only when applicable.
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This is intended to be used as a minibuffer `post-command-hook' for
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`minibuffer-electric-default-mode'; the minibuffer should have already
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been set up by `minibuf-eldef-setup-minibuffer'."
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(unless (eq minibuf-eldef-showing-default-in-prompt
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(and (= (point-max) minibuf-eldef-initial-buffer-length)
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(string-equal (minibuffer-contents-no-properties)
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minibuf-eldef-initial-input)))
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;; Swap state.
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(setq minibuf-eldef-showing-default-in-prompt
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(not minibuf-eldef-showing-default-in-prompt))
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(overlay-put minibuf-eldef-overlay 'invisible
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(not minibuf-eldef-showing-default-in-prompt))))
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;;;###autoload
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(define-minor-mode minibuffer-electric-default-mode
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"Toggle Minibuffer Electric Default mode.
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Minibuffer Electric Default mode is a global minor mode. When
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enabled, minibuffer prompts that show a default value only show
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the default when it's applicable -- that is, when hitting RET
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would yield the default value. If the user modifies the input
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such that hitting RET would enter a non-default value, the prompt
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is modified to remove the default indication."
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:global t
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:group 'minibuffer
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(if minibuffer-electric-default-mode
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;; Enable the mode
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(add-hook 'minibuffer-setup-hook 'minibuf-eldef-setup-minibuffer)
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;; Disable the mode
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(remove-hook 'minibuffer-setup-hook 'minibuf-eldef-setup-minibuffer)
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;; Remove our entry from any post-command-hook variable's it's still in
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(dolist (minibuf minibuf-eldef-frobbed-minibufs)
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(with-current-buffer minibuf
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(remove-hook 'post-command-hook #'minibuf-eldef-update-minibuffer t)))
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(setq minibuf-eldef-frobbed-minibufs nil)))
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(provide 'minibuf-eldef)
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;;; minibuf-eldef.el ends here
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