Subject: Re: bug#12443: 24.2.50; Default values in the minibuffer prompt (fix inconsisntecy)

From: Stefan Monnier <[email-masked]>
Date: Fri, 14 Sep 2012 11:56:50 -0400

> I see no reason for this inconsistency,

Agreed.  The officially sanctioned behavior is to use "(default ...)".

> neither I see the need for the "default " part.

That would make the job of minibuffer-electric-default-mode harder
(more false positives).

> So, hereby I propose to fix this, i.e., to omit the "default " in
> those commands where this is currently shown.

I find the "(default ...)" text to use up too much space for my own taste, so
I use the patch below to rewrite it on-the-fly to "[...]".

        Stefan

Using submit branch file:///home/monnier/src/emacs/bzr/trunk/
=== modified file 'lisp/minibuf-eldef.el'
--- lisp/minibuf-eldef.el	2012-04-09 13:05:48 +0000
+++ lisp/minibuf-eldef.el	2012-09-14 15:54:47 +0000
@@ -34,15 +34,17 @@
 ;;; Code:
 
 (defvar minibuffer-default-in-prompt-regexps
-  '(("\\( (default\\>.*)\\):? \\'" . 1) ("\\( \\[.*\\]\\):? *\\'" . 1))
+  '(("\\( (default\\(?: is\\)? \\(.*\\))\\):? \\'" 1 " [\\2]")
+    ("\\( \\[.*\\]\\):? *\\'" 1))
   "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 either a string, which should be a regexp matching the
-default portion of the prompt, or a cons cell, who's car is a regexp
-matching the default part of the prompt, and who's cdr indicates the
-regexp subexpression that matched.")
+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
@@ -85,15 +87,25 @@
 	;; See the prompt contains a default input indicator
 	(while regexps
 	  (setq match (pop regexps))
-	  (if (re-search-forward (if (stringp match) match (car match)) nil t)
-	      (setq regexps nil)
+	  (if (re-search-forward (car match) nil t)
+              (if (consp (cddr match))
+                  (let ((inhibit-read-only t)
+                        (buffer-undo-list t)
+                        (props (text-properties-at (match-beginning (cadr match)))))
+                    (replace-match (caddr match) nil nil nil (cadr match))
+                    (set-text-properties (match-beginning (cadr match))
+                                         (match-end (cadr match))
+                                         props)
+                    (setq match nil)
+                    (goto-char (point-min)))
+                (setq regexps nil))
 	    (setq match nil)))))
     (if (not match)
 	;; Nope, 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 (cadr match))
       (setq minibuf-eldef-overlay
 	    (make-overlay (match-beginning match) (match-end match)))
       (setq minibuf-eldef-showing-default-in-prompt t)
@@ -124,10 +136,6 @@
 	   (overlay-put minibuf-eldef-overlay 'intangible t)))))
 
 
-;;; Note this definition must be at the end of the file, because
-;;; `define-minor-mode' actually calls the mode-function if the
-;;; associated variable is non-nil, which requires that all needed
-;;; functions be already defined.  [This is arguably a bug in d-m-m]
 ;;;###autoload
 (define-minor-mode minibuffer-electric-default-mode
   "Toggle Minibuffer Electric Default mode.