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|
;;; minibuf-eldef.el --- Only show defaults in prompts when applicable -*- lexical-binding: t -*-
;;
;; Copyright (C) 2000-2022 Free Software Foundation, Inc.
;;
;; Author: Miles Bader <miles@gnu.org>
;; Keywords: convenience
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;;
;; Defines the mode `minibuffer-electric-default-mode'.
;;
;; When active, minibuffer prompts that show a default value only show
;; the default when it's applicable -- that is, when hitting RET would
;; yield the default value. If the user modifies the input such that
;; hitting RET would enter a non-default value, the prompt is modified
;; to remove the default indication (which is restored if the input is
;; ever restore to the match the initial input).
;;; Code:
(defvar minibuffer-eldef-shorten-default)
(defun minibuffer-default--in-prompt-regexps ()
(cons
(list
(concat
"\\("
(if (string-match "%s" minibuffer-default-prompt-format)
(concat
(regexp-quote (substring minibuffer-default-prompt-format
0 (match-beginning 0)))
"\\(.*?\\)"
(regexp-quote (substring minibuffer-default-prompt-format
(match-end 0))))
(regexp-quote minibuffer-default-prompt-format))
"\\): ")
1 (and minibuffer-eldef-shorten-default " [\\2]"))
`(("\\( (default\\(?: is\\)? \\(.*\\))\\):? \\'"
1 ,(if minibuffer-eldef-shorten-default " [\\2]"))
("([^(]+?\\(, default\\(?: is\\)? \\(.*\\)\\)):? \\'" 1)
("\\( \\[.*\\]\\):? *\\'" 1))))
(defcustom minibuffer-eldef-shorten-default nil
"If non-nil, shorten \"(default ...)\" to \"[...]\" in minibuffer prompts."
:set (lambda (symbol value)
(set-default symbol value)
(setq-default minibuffer-default-in-prompt-regexps
(minibuffer-default--in-prompt-regexps)))
:type 'boolean
:group 'minibuffer
:version "24.3")
(defvar minibuffer-default-in-prompt-regexps
(minibuffer-default--in-prompt-regexps)
"A list of regexps matching the parts of minibuffer prompts showing defaults.
When `minibuffer-electric-default-mode' is active, these regexps are
used to identify the portions of prompts to elide.
Each entry is of the form (REGEXP MATCH-NUM &optional REWRITE),
where REGEXP should match the default part of the prompt,
MATCH-NUM is the subgroup that matched the actual default indicator,
and REWRITE, if present, is a string to pass to `replace-match' that
should be displayed in its place.")
;;; Internal variables
;; A list of minibuffers to which we've added a post-command-hook.
(defvar minibuf-eldef-frobbed-minibufs nil)
;;; The following are all local variables in the minibuffer
;; Input pre-inserted into the minibuffer before the user can edit it.
(defvar minibuf-eldef-initial-input)
(make-variable-buffer-local 'minibuf-eldef-initial-input)
;; and the length of the buffer with it inserted.
(defvar minibuf-eldef-initial-buffer-length)
(make-variable-buffer-local 'minibuf-eldef-initial-buffer-length)
;; True if the current minibuffer prompt contains the default spec.
(defvar minibuf-eldef-showing-default-in-prompt)
(make-variable-buffer-local 'minibuf-eldef-showing-default-in-prompt)
;; An overlay covering the default portion of the prompt
(defvar minibuf-eldef-overlay)
(make-variable-buffer-local 'minibuf-eldef-overlay)
;;; Hook functions
;; This function goes on minibuffer-setup-hook
(defun minibuf-eldef-setup-minibuffer ()
"Set up a minibuffer for `minibuffer-electric-default-mode'.
The prompt and initial input should already have been inserted."
(let ((regexps minibuffer-default-in-prompt-regexps)
(match nil)
(inhibit-point-motion-hooks t))
(save-excursion
(save-restriction
;; Narrow to only the prompt.
(goto-char (point-min))
(narrow-to-region (point) (minibuffer-prompt-end))
;; See if the prompt contains a default input indicator.
(while regexps
(setq match (pop regexps))
(cond
((not (re-search-forward (if (stringp match) match (car match))
nil t))
;; No match yet, try the next rule.
(setq match nil))
((and (consp (cdr-safe match)) (nth 2 match))
;; Matched a replacement rule.
(let* ((inhibit-read-only t)
(buffer-undo-list t)
(submatch (nth 1 match))
(replacement (nth 2 match))
(props (text-properties-at (match-beginning submatch))))
(replace-match replacement nil nil nil submatch)
(set-text-properties (match-beginning submatch)
(match-end submatch)
props)
;; Replacement done, now keep trying with subsequent rules.
(setq match nil)
(goto-char (point-min))))
;; Matched a non-replacement (i.e. electric hide) rule, no need to
;; keep trying.
(t (setq regexps nil))))))
(if (not match)
;; No match for electric hiding, so just make sure our
;; post-command-hook isn't left around.
(remove-hook 'post-command-hook #'minibuf-eldef-update-minibuffer t)
;; Yup; set things up so we can frob the prompt as the state of
;; the input string changes.
(setq match (if (consp match) (cdr match) 0))
(setq match (if (consp match) (car match) match))
(setq minibuf-eldef-overlay
(make-overlay (match-beginning match) (match-end match)))
(setq minibuf-eldef-showing-default-in-prompt t)
(setq minibuf-eldef-initial-input
(minibuffer-contents-no-properties))
(setq minibuf-eldef-initial-buffer-length (point-max))
(add-to-list 'minibuf-eldef-frobbed-minibufs (current-buffer))
(add-hook 'post-command-hook #'minibuf-eldef-update-minibuffer nil t))))
;; post-command-hook to swap prompts when necessary
(defun minibuf-eldef-update-minibuffer ()
"Update a minibuffer's prompt to include a default only when applicable.
This is intended to be used as a minibuffer `post-command-hook' for
`minibuffer-electric-default-mode'; the minibuffer should have already
been set up by `minibuf-eldef-setup-minibuffer'."
(unless (eq minibuf-eldef-showing-default-in-prompt
(and (= (point-max) minibuf-eldef-initial-buffer-length)
(string-equal (minibuffer-contents-no-properties)
minibuf-eldef-initial-input)))
;; Swap state.
(setq minibuf-eldef-showing-default-in-prompt
(not minibuf-eldef-showing-default-in-prompt))
(overlay-put minibuf-eldef-overlay 'invisible
(not minibuf-eldef-showing-default-in-prompt))))
;;;###autoload
(define-minor-mode minibuffer-electric-default-mode
"Toggle Minibuffer Electric Default mode.
Minibuffer Electric Default mode is a global minor mode. When
enabled, minibuffer prompts that show a default value only show
the default when it's applicable -- that is, when hitting RET
would yield the default value. If the user modifies the input
such that hitting RET would enter a non-default value, the prompt
is modified to remove the default indication."
:global t
:group 'minibuffer
(if minibuffer-electric-default-mode
;; Enable the mode
(add-hook 'minibuffer-setup-hook 'minibuf-eldef-setup-minibuffer)
;; Disable the mode
(remove-hook 'minibuffer-setup-hook 'minibuf-eldef-setup-minibuffer)
;; Remove our entry from any post-command-hook variable's it's still in
(dolist (minibuf minibuf-eldef-frobbed-minibufs)
(with-current-buffer minibuf
(remove-hook 'post-command-hook #'minibuf-eldef-update-minibuffer t)))
(setq minibuf-eldef-frobbed-minibufs nil)))
(provide 'minibuf-eldef)
;;; minibuf-eldef.el ends here
|
