;;; minibuf-eldef.el --- Only show defaults in prompts when applicable -*- lexical-binding: t -*- ;; ;; Copyright (C) 2000-2023 Free Software Foundation, Inc. ;; ;; Author: Miles Bader ;; 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 . ;;; 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") (make-obsolete-variable 'minibuffer-eldef-shorten-default 'minibuffer-default-prompt-format "29.1") (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)) (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