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163 lines
6.6 KiB
EmacsLisp
163 lines
6.6 KiB
EmacsLisp
;;; minibuf-eldef.el --- Only show defaults in prompts when applicable
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;;
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;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
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;; 2005 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 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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;;
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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-default-in-prompt-regexps
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'(("\\( (default\\>.*)\\):? \\'" . 1) ("\\( \\[.*\\]\\):? *\\'" . 1))
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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 either a string, which should be a regexp matching the
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default portion of the prompt, or a cons cell, who's car is a regexp
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matching the default part of the prompt, and who's cdr indicates the
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regexp subexpression that matched.")
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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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(inhibit-point-motion-hooks t))
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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 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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(if (re-search-forward (if (stringp match) match (car match)) nil t)
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(setq regexps nil)
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(setq match nil)))))
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(if (not match)
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;; Nope, so just make sure our 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 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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(cond (minibuf-eldef-showing-default-in-prompt
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(overlay-put minibuf-eldef-overlay 'invisible nil)
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(overlay-put minibuf-eldef-overlay 'intangible nil))
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(t
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(overlay-put minibuf-eldef-overlay 'invisible t)
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(overlay-put minibuf-eldef-overlay 'intangible t)))))
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;;; Note this definition must be at the end of the file, because
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;;; `define-minor-mode' actually calls the mode-function if the
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;;; associated variable is non-nil, which requires that all needed
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;;; functions be already defined. [This is arguably a bug in d-m-m]
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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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When active, minibuffer prompts that show a default value only show the
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default when it's applicable -- that is, when hitting RET would yield
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the default value. If the user modifies the input such that hitting RET
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would enter a non-default value, the prompt is modified to remove the
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default indication.
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With prefix argument ARG, turn on if positive, otherwise off.
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Returns non-nil if the new state is enabled."
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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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;; arch-tag: 7e421fae-c275-4729-b0da-7836af377d3d
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;;; minibuf-eldef.el ends here
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