* lisp/replace.el: History for query replace pairs.

(query-replace-defaults): Promote to a list of cons cell.  Doc fix.
(query-replace-from-to-separator): New variable.
(query-replace-read-from): Let-bind query-replace-from-to-history
to a list of FROM-TO strings created from query-replace-defaults
and separated by query-replace-from-to-separator.  Use it as
the history while reading from the minibuffer.  Split the returned
string by the separator to get FROM and TO parts, and add them
to the history variables.
(query-replace-read-to): Add FROM-TO pairs to query-replace-defaults.
(query-replace-regexp-eval): Let-bind query-replace-defaults to nil.
http://lists.gnu.org/archive/html/emacs-devel/2014-11/msg00253.html

* lisp/isearch.el (isearch-text-char-description): Keep characters
intact and put formatted strings with the `display' property.

lisp/ChangeLog

@@ -1,3 +1,21 @@
+2014-11-07  Juri Linkov  <juri@jurta.org>
+
+	* replace.el: History for query replace pairs.
+	(query-replace-defaults): Promote to a list of cons cell.  Doc fix.
+	(query-replace-from-to-separator): New variable.
+	(query-replace-read-from): Let-bind query-replace-from-to-history
+	to a list of FROM-TO strings created from query-replace-defaults
+	and separated by query-replace-from-to-separator.  Use it as
+	the history while reading from the minibuffer.  Split the returned
+	string by the separator to get FROM and TO parts, and add them
+	to the history variables.
+	(query-replace-read-to): Add FROM-TO pairs to query-replace-defaults.
+	(query-replace-regexp-eval): Let-bind query-replace-defaults to nil.
+	http://lists.gnu.org/archive/html/emacs-devel/2014-11/msg00253.html
+
+	* isearch.el (isearch-text-char-description): Keep characters
+	intact and put formatted strings with the `display' property.
+
 2014-11-07  Martin Rudalics  <rudalics@gmx.at>
 
 	* cus-start.el (frame-resize-pixelwise): Fix group.

lisp/isearch.el

@@ -2873,8 +2873,12 @@ since they have special meaning in a regexp."
 
 (defun isearch-text-char-description (c)
   (cond
-   ((< c ?\s) (propertize (format "^%c" (+ c 64)) 'face 'escape-glyph))
-   ((= c ?\^?) (propertize "^?" 'face 'escape-glyph))
+   ((< c ?\s) (propertize
+	       (char-to-string c)
+	       'display (propertize (format "^%c" (+ c 64)) 'face 'escape-glyph)))
+   ((= c ?\^?) (propertize
+		(char-to-string c)
+		'display (propertize "^?" 'face 'escape-glyph)))
    (t (char-to-string c))))
 
 ;; General function to unread characters or events.

lisp/replace.el

@@ -56,8 +56,8 @@ See `query-replace-from-history-variable' and
 
 (defvar query-replace-defaults nil
   "Default values of FROM-STRING and TO-STRING for `query-replace'.
-This is a cons cell (FROM-STRING . TO-STRING), or nil if there is
-no default value.")
+This is a list of cons cells (FROM-STRING . TO-STRING), or nil
+if there are no default values.")
 
 (defvar query-replace-interactive nil
   "Non-nil means `query-replace' uses the last search string.
@@ -67,6 +67,12 @@ That becomes the \"string to replace\".")
 to the minibuffer that reads the string to replace, or invoke replacements
 from Isearch by using a key sequence like `C-s C-s M-%'." "24.3")
 
+(defvar query-replace-from-to-separator
+  (propertize "\0"
+	      'display (propertize " \u2192 " 'face 'minibuffer-prompt)
+	      'separator t)
+  "String that separates FROM and TO in the history of replacement pairs.")
+
 (defcustom query-replace-from-history-variable 'query-replace-history
   "History list to use for the FROM argument of `query-replace' commands.
 The value of this variable should be a symbol; that symbol
@@ -132,11 +138,19 @@ wants to replace FROM with TO."
   (if query-replace-interactive
       (car (if regexp-flag regexp-search-ring search-ring))
     (let* ((history-add-new-input nil)
+	   (query-replace-from-to-history
+	    (append
+	     (when query-replace-from-to-separator
+	       (mapcar (lambda (from-to)
+			 (concat (query-replace-descr (car from-to))
+				 query-replace-from-to-separator
+				 (query-replace-descr (cdr from-to))))
+		       query-replace-defaults))
+	     (symbol-value query-replace-from-history-variable)))
+	   (minibuffer-allow-text-properties t) ; separator uses text-properties
 	   (prompt
-	    (if query-replace-defaults
-		(format "%s (default %s -> %s): " prompt
-			(query-replace-descr (car query-replace-defaults))
-			(query-replace-descr (cdr query-replace-defaults)))
+	    (if (and query-replace-defaults query-replace-from-to-separator)
+		(format "%s (default %s): " prompt (car query-replace-from-to-history))
 	      (format "%s: " prompt)))
 	   (from
 	    ;; The save-excursion here is in case the user marks and copies
@@ -144,26 +158,36 @@ wants to replace FROM with TO."
 	    ;; That should not clobber the region for the query-replace itself.
 	    (save-excursion
 	      (if regexp-flag
-		  (read-regexp prompt nil query-replace-from-history-variable)
+		  (read-regexp prompt nil 'query-replace-from-to-history)
 		(read-from-minibuffer
-		 prompt nil nil nil query-replace-from-history-variable
+		 prompt nil nil nil 'query-replace-from-to-history
 		 (car (if regexp-flag regexp-search-ring search-ring)) t)))))
       (if (and (zerop (length from)) query-replace-defaults)
-	  (cons (car query-replace-defaults)
+	  (cons (caar query-replace-defaults)
 		(query-replace-compile-replacement
-		 (cdr query-replace-defaults) regexp-flag))
-	(add-to-history query-replace-from-history-variable from nil t)
-	;; Warn if user types \n or \t, but don't reject the input.
-	(and regexp-flag
-	     (string-match "\\(\\`\\|[^\\]\\)\\(\\\\\\\\\\)*\\(\\\\[nt]\\)" from)
-	     (let ((match (match-string 3 from)))
-	       (cond
-		((string= match "\\n")
-		 (message "Note: `\\n' here doesn't match a newline; to do that, type C-q C-j instead"))
-		((string= match "\\t")
-		 (message "Note: `\\t' here doesn't match a tab; to do that, just type TAB")))
-	       (sit-for 2)))
-	from))))
+		 (cdar query-replace-defaults) regexp-flag))
+	(let* ((to (if (and (string-match query-replace-from-to-separator from)
+			    (get-text-property (match-beginning 0) 'separator from))
+		       (query-replace-compile-replacement
+			(substring-no-properties from (match-end 0)) regexp-flag)))
+	       (from (if to (substring-no-properties from 0 (match-beginning 0))
+		       (substring-no-properties from))))
+	  (add-to-history query-replace-from-history-variable from nil t)
+	  ;; Warn if user types \n or \t, but don't reject the input.
+	  (and regexp-flag
+	       (string-match "\\(\\`\\|[^\\]\\)\\(\\\\\\\\\\)*\\(\\\\[nt]\\)" from)
+	       (let ((match (match-string 3 from)))
+		 (cond
+		  ((string= match "\\n")
+		   (message "Note: `\\n' here doesn't match a newline; to do that, type C-q C-j instead"))
+		  ((string= match "\\t")
+		   (message "Note: `\\t' here doesn't match a tab; to do that, just type TAB")))
+		 (sit-for 2)))
+	  (if (not to)
+	      from
+	    (add-to-history query-replace-to-history-variable to nil t)
+	    (add-to-history 'query-replace-defaults (cons from to) nil t)
+	    (cons from to)))))))
 
 (defun query-replace-compile-replacement (to regexp-flag)
   "Maybe convert a regexp replacement TO to Lisp.
@@ -216,7 +240,7 @@ the original string if not."
 		 nil nil nil
 		 query-replace-to-history-variable from t)))
        (add-to-history query-replace-to-history-variable to nil t)
-       (setq query-replace-defaults (cons from to))
+       (add-to-history 'query-replace-defaults (cons from to) nil t)
        to))
    regexp-flag))
 
@@ -421,7 +445,7 @@ for Lisp calls." "22.1"))
 	     ;; Let-bind the history var to disable the "foo -> bar"
 	     ;; default.  Maybe we shouldn't disable this default, but
 	     ;; for now I'll leave it off.  --Stef
-	     (let ((query-replace-to-history-variable nil))
+	     (let ((query-replace-defaults nil))
 	       (query-replace-read-from "Query replace regexp" t)))
 	    (to (list (read-from-minibuffer
 		       (format "Query replace regexp %s with eval: "