Toggle whitespace matching mode with M-s SPC.

http://lists.gnu.org/archive/html/emacs-devel/2012-09/msg00008.html

* lisp/isearch.el (search-whitespace-regexp): Doc fix.
Remove cons cell customization.
(isearch-mode-map): Bind "\M-s " to isearch-toggle-lax-whitespace.
(isearch-lax-whitespace, isearch-regexp-lax-whitespace):
New variables.
(isearch-forward, isearch-forward-regexp): Doc fix.
(isearch-toggle-lax-whitespace): New command.
(search-forward-lax-whitespace, search-backward-lax-whitespace)
(re-search-forward-lax-whitespace)
(re-search-backward-lax-whitespace): New functions.
(isearch-whitespace-regexp): Remove function.
(isearch-query-replace): Let-bind replace-search-function and
replace-re-search-function.
(isearch-occur): Let-bind search-spaces-regexp according to the
value of isearch-lax-whitespace and isearch-regexp-lax-whitespace.
(isearch-quote-char): Check isearch-regexp-lax-whitespace in the
condition for C-q SPC.
(isearch-search-fun-default): Use new functions mentioned above.
(isearch-search-forward, isearch-search-backward): Remove functions.
(isearch-search): Don't let-bind search-spaces-regexp.
(isearch-lazy-highlight-space-regexp): Remove variable.
(isearch-lazy-highlight-lax-whitespace)
(isearch-lazy-highlight-regexp-lax-whitespace): New variables.
(isearch-lazy-highlight-new-loop): Use them.
(isearch-lazy-highlight-search): Don't let-bind search-spaces-regexp.

3 files changed, 147 insertions, 47 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 1dc8db5fa04..45966e53882 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -183,12 +183,14 @@ end of the buffer.  It defaults to t.
 and `M-s _' in Isearch toggles symbol search mode.
 `M-s c' in Isearch toggles search case-sensitivity.
 
-*** `search-whitespace-regexp' now acts on ordinary incremental search
-as well, so that each sequence of spaces in the search string matches
-any combination of one or more whitespace characters.  To change this
-behavior, you can give `search-whitespace-regexp' a cons cell value,
-where the car and cdr specify values for ordinary and regular
-expression incremental search respectively.
+*** `M-s SPC' in Isearch toggles whitespace matching mode
+in both ordinary and regexp incremental search, so that each
+sequence of spaces in the search string matches any combination
+of one or more whitespace characters defined by the variable
+`search-whitespace-regexp'.  In ordinary incremental search,
+`isearch-toggle-lax-whitespace' toggles the value of the variable
+`isearch-lax-whitespace'.  In regexp incremental search, it toggles
+the value of the variable `isearch-regexp-lax-whitespace'.
 
 ** M-x move-to-column, if called interactively with no prefix arg, now
 prompts for a column number.
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index d018e455357..b56672ac84f 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,34 @@
+2012-09-02  Juri Linkov  <juri@jurta.org>
+
+        Toggle whitespace matching mode with M-s SPC.
+        http://lists.gnu.org/archive/html/emacs-devel/2012-09/msg00008.html
+
+        * isearch.el (search-whitespace-regexp): Doc fix.
+        Remove cons cell customization.
+        (isearch-mode-map): Bind "\M-s " to isearch-toggle-lax-whitespace.
+        (isearch-lax-whitespace, isearch-regexp-lax-whitespace):
+        New variables.
+        (isearch-forward, isearch-forward-regexp): Doc fix.
+        (isearch-toggle-lax-whitespace): New command.
+        (search-forward-lax-whitespace, search-backward-lax-whitespace)
+        (re-search-forward-lax-whitespace)
+        (re-search-backward-lax-whitespace): New functions.
+        (isearch-whitespace-regexp): Remove function.
+        (isearch-query-replace): Let-bind replace-search-function and
+        replace-re-search-function.
+        (isearch-occur): Let-bind search-spaces-regexp according to the
+        value of isearch-lax-whitespace and isearch-regexp-lax-whitespace.
+        (isearch-quote-char): Check isearch-regexp-lax-whitespace in the
+        condition for C-q SPC.
+        (isearch-search-fun-default): Use new functions mentioned above.
+        (isearch-search-forward, isearch-search-backward): Remove functions.
+        (isearch-search): Don't let-bind search-spaces-regexp.
+        (isearch-lazy-highlight-space-regexp): Remove variable.
+        (isearch-lazy-highlight-lax-whitespace)
+        (isearch-lazy-highlight-regexp-lax-whitespace): New variables.
+        (isearch-lazy-highlight-new-loop): Use them.
+        (isearch-lazy-highlight-search): Don't let-bind search-spaces-regexp.
+
 2012-09-02  Chong Yidong  <cyd@gnu.org>
 
         * dired.el (dired-mode-map): Menu string fixes (Bug#11616).
diff --git a/lisp/isearch.el b/lisp/isearch.el
index 6ea8d86336a..e6e0a01566a 100644
--- a/lisp/isearch.el
+++ b/lisp/isearch.el
@@ -116,24 +116,16 @@ will match any sequence matched by this regexp.  As an exception,
 spaces are treated normally in regexp incremental search if they
 occur in a regexp construct like [...] or *, + or ?.
 
-If the value is a string, it applies to both ordinary and regexp
-incremental search.  If the value is nil, each space you type
-matches literally, against one space.
-
-The value can also be a cons cell (REGEXP-1 . REGEXP-2).  In that
-case, REGEXP-1 is used as the value for ordinary incremental
-search, and REGEXP-2 is used for regexp incremental search.
+If the value is a string, it applies to both ordinary and
+regexp incremental search.  If the value is nil, or
+`isearch-lax-whitespace' is nil for ordinary incremental search, or
+`isearch-regexp-lax-whitespace' is nil for regexp incremental search,
+then each space you type matches literally, against one space.
 
 You might want to use something like \"[ \\t\\r\\n]+\" instead.
 In the Customization buffer, that is `[' followed by a space,
 a tab, a carriage return (control-M), a newline, and `]+'."
-  :type '(choice (const :tag "Treat Spaces Literally" nil)
-                 (cons (choice :tag "For Ordinary Isearch"
-                               regexp
-                               (const :tag "Treat Spaces Literally" nil))
-                       (choice :tag "For Regexp Isearch"
-                               regexp
-                               (const :tag "Treat Spaces Literally" nil)))
+  :type '(choice (const :tag "Match Spaces Literally" nil)
                  regexp)
   :group 'isearch
   :version "24.3")
@@ -514,6 +506,7 @@ This is like `describe-bindings', but displays only Isearch keys."
     (define-key map "\M-sr" 'isearch-toggle-regexp)
     (define-key map "\M-sw" 'isearch-toggle-word)
     (define-key map "\M-s_" 'isearch-toggle-symbol)
+    (define-key map "\M-s " 'isearch-toggle-lax-whitespace)
 
     (define-key map [?\M-%] 'isearch-query-replace)
     (define-key map [?\C-\M-%] 'isearch-query-replace-regexp)
@@ -556,6 +549,22 @@ convert the search string to a regexp used by regexp search functions.
 The property `isearch-message-prefix' put on this function specifies the
 prefix string displayed in the search message.")
 
+(defvar isearch-lax-whitespace t
+  "If non-nil, a space will match a sequence of whitespace chars.
+When you enter a space or spaces in ordinary incremental search, it
+will match any sequence matched by the regexp defined by the variable
+`search-whitespace-regexp'.  If the value is nil, each space you type
+matches literally, against one space.  You can toggle the value of this
+variable by the command `isearch-toggle-lax-whitespace'.")
+
+(defvar isearch-regexp-lax-whitespace nil
+  "If non-nil, a space will match a sequence of whitespace chars.
+When you enter a space or spaces in regexp incremental search, it
+will match any sequence matched by the regexp defined by the variable
+`search-whitespace-regexp'.  If the value is nil, each space you type
+matches literally, against one space.  You can toggle the value of this
+variable by the command `isearch-toggle-lax-whitespace'.")
+
 (defvar isearch-cmds nil
   "Stack of search status sets.
 Each set is a vector of the form:
@@ -681,6 +690,12 @@ Type \\[isearch-toggle-case-fold] to toggle search case-sensitivity.
 Type \\[isearch-toggle-regexp] to toggle regular-expression mode.
 Type \\[isearch-toggle-word] to toggle word mode.
 Type \\[isearch-toggle-symbol] to toggle symbol mode.
+
+Type \\[isearch-toggle-lax-whitespace] to toggle whitespace matching.
+In incremental searches, a space or spaces normally matches any whitespace
+defined by the variable `search-whitespace-regexp'; see also the variables
+`isearch-lax-whitespace' and `isearch-regexp-lax-whitespace'.
+
 Type \\[isearch-edit-string] to edit the search string in the minibuffer.
 
 Also supported is a search ring of the previous 16 search strings.
@@ -702,9 +717,6 @@ Type \\[isearch-describe-bindings] to display all Isearch key bindings.
 Type \\[isearch-describe-key] to display documentation of Isearch key.
 Type \\[isearch-describe-mode] to display documentation of Isearch mode.
 
-In incremental searches, a space or spaces normally matches any
-whitespace; see the variable `search-whitespace-regexp'.
-
 If an input method is turned on in the current buffer, that input
 method is also active while you are typing characters to search.
 To toggle the input method, type \\[isearch-toggle-input-method].  \
@@ -734,8 +746,9 @@ Like ordinary incremental search except that your input is treated
 as a regexp.  See the command `isearch-forward' for more information.
 
 In incremental searches, a space or spaces normally matches any
-whitespace; see the variable `search-whitespace-regexp'.  To
-search for a literal space and nothing else, enter C-q SPC."
+whitespace defined by the variable `search-whitespace-regexp'.
+To search for a literal space and nothing else, enter C-q SPC.
+To toggle whitespace matching, use `isearch-toggle-lax-whitespace'."
   (interactive "P\np")
   (isearch-mode t (null not-regexp) nil (not no-recursive-edit)))
 
@@ -1395,6 +1408,28 @@ Use `isearch-exit' to quit without signaling."
   (setq isearch-success t isearch-adjusted t)
   (isearch-update))
 
+(defun isearch-toggle-lax-whitespace ()
+  "Toggle whitespace matching in searching on or off.
+In ordinary search, toggles the value of the variable
+`isearch-lax-whitespace'.  In regexp search, toggles the
+value of the variable `isearch-regexp-lax-whitespace'."
+  (interactive)
+  (if isearch-regexp
+      (setq isearch-regexp-lax-whitespace (not isearch-regexp-lax-whitespace))
+    (setq isearch-lax-whitespace (not isearch-lax-whitespace)))
+  (let ((message-log-max nil))
+    (message "%s%s [%s]"
+             (isearch-message-prefix nil isearch-nonincremental)
+             isearch-message
+             (if (if isearch-regexp
+                     isearch-regexp-lax-whitespace
+                   isearch-lax-whitespace)
+                 "match spaces loosely"
+               "match spaces literally")))
+  (setq isearch-success t isearch-adjusted t)
+  (sit-for 1)
+  (isearch-update))
+
 (defun isearch-toggle-case-fold ()
   "Toggle case folding in searching on or off."
   (interactive)
@@ -1506,6 +1541,28 @@ If LAX is non-nil, the end of the string need not match a symbol boundary."
 
 (put 'isearch-symbol-regexp 'isearch-message-prefix "symbol ")
 
+;; Search with lax whitespace
+
+(defun search-forward-lax-whitespace (string &optional bound noerror count)
+  "Search forward for STRING, matching a sequence of whitespace chars."
+  (let ((search-spaces-regexp search-whitespace-regexp))
+    (re-search-forward (regexp-quote string) bound noerror count)))
+
+(defun search-backward-lax-whitespace (string &optional bound noerror count)
+  "Search backward for STRING, matching a sequence of whitespace chars."
+  (let ((search-spaces-regexp search-whitespace-regexp))
+    (re-search-backward (regexp-quote string) bound noerror count)))
+
+(defun re-search-forward-lax-whitespace (regexp &optional bound noerror count)
+  "Search forward for REGEXP, matching a sequence of whitespace chars."
+  (let ((search-spaces-regexp search-whitespace-regexp))
+    (re-search-forward regexp bound noerror count)))
+
+(defun re-search-backward-lax-whitespace (regexp &optional bound noerror count)
+  "Search backward for REGEXP, matching a sequence of whitespace chars."
+  (let ((search-spaces-regexp search-whitespace-regexp))
+    (re-search-backward regexp bound noerror count)))
+
 
 (defun isearch-query-replace (&optional delimited regexp-flag)
   "Start `query-replace' with string to replace from last search string.
@@ -1522,6 +1579,14 @@ way to run word replacements from Isearch is `M-s w ... M-%'."
         ;; set `search-upper-case' to nil to not call
         ;; `isearch-no-upper-case-p' in `perform-replace'
         (search-upper-case nil)
+        (replace-search-function
+         (if (and isearch-lax-whitespace (not regexp-flag))
+             #'search-forward-lax-whitespace
+           replace-search-function))
+        (replace-re-search-function
+         (if (and isearch-regexp-lax-whitespace regexp-flag)
+             #'re-search-forward-lax-whitespace
+           replace-re-search-function))
         ;; Set `isearch-recursive-edit' to nil to prevent calling
         ;; `exit-recursive-edit' in `isearch-done' that terminates
         ;; the execution of this command when it is non-nil.
@@ -1558,15 +1623,6 @@ See `isearch-query-replace' for more information."
    (list current-prefix-arg))
   (isearch-query-replace delimited t))
 
-(defun isearch-whitespace-regexp ()
-  "Return the value of `search-whitespace-regexp' for the current search."
-  (cond ((not (consp search-whitespace-regexp))
-         search-whitespace-regexp)
-        (isearch-regexp
-         (cdr search-whitespace-regexp))
-        (t
-         (car search-whitespace-regexp))))
-
 (defun isearch-occur (regexp &optional nlines)
   "Run `occur' using the last search string as the regexp.
 Interactively, REGEXP is constructed using the search string from the
@@ -1606,7 +1662,11 @@ characters in that string."
         ;; Set `search-upper-case' to nil to not call
         ;; `isearch-no-upper-case-p' in `occur-1'.
         (search-upper-case nil)
-        (search-spaces-regexp (isearch-whitespace-regexp)))
+        (search-spaces-regexp
+         (if (if isearch-regexp
+                 isearch-regexp-lax-whitespace
+               isearch-lax-whitespace)
+             search-whitespace-regexp)))
     (occur regexp nlines)))
 
 (declare-function hi-lock-read-face-name "hi-lock" ())
@@ -2203,7 +2263,7 @@ Isearch mode."
     ;; Assume character codes 0200 - 0377 stand for characters in some
     ;; single-byte character set, and convert them to Emacs
     ;; characters.
-    (if (and isearch-regexp (= char ?\s))
+    (if (and isearch-regexp isearch-regexp-lax-whitespace (= char ?\s))
         (if (subregexp-context-p isearch-string (length isearch-string))
             (isearch-process-search-string "[ ]" " ")
           (isearch-process-search-char char))
@@ -2443,16 +2503,19 @@ Can be changed via `isearch-search-fun-function' for special needs."
              (funcall isearch-word string lax)
            (word-search-regexp string lax))
          bound noerror count))))
+   ((and isearch-regexp isearch-regexp-lax-whitespace
+         search-whitespace-regexp)
+    (if isearch-forward
+        're-search-forward-lax-whitespace
+      're-search-backward-lax-whitespace))
    (isearch-regexp
     (if isearch-forward 're-search-forward 're-search-backward))
+   ((and isearch-lax-whitespace search-whitespace-regexp)
+    (if isearch-forward
+        'search-forward-lax-whitespace
+      'search-backward-lax-whitespace))
    (t
-    (if isearch-forward 'isearch-search-forward 'isearch-search-backward))))
-
-(defun isearch-search-forward (string &optional bound noerror count)
-  (re-search-forward (regexp-quote string) bound noerror count))
-
-(defun isearch-search-backward (string &optional bound noerror count)
-  (re-search-backward (regexp-quote string) bound noerror count))
+    (if isearch-forward 'search-forward 'search-backward))))
 
 (defun isearch-search-string (string bound noerror)
   "Search for the first occurrence of STRING or its translation.
@@ -2513,7 +2576,6 @@ update the match data, and return point."
                   search-invisible))
             (inhibit-quit nil)
             (case-fold-search isearch-case-fold-search)
-            (search-spaces-regexp (isearch-whitespace-regexp))
             (retry t))
         (setq isearch-error nil)
         (while retry
@@ -2805,7 +2867,8 @@ since they have special meaning in a regexp."
 (defvar isearch-lazy-highlight-window-end nil)
 (defvar isearch-lazy-highlight-case-fold-search nil)
 (defvar isearch-lazy-highlight-regexp nil)
-(defvar isearch-lazy-highlight-space-regexp nil)
+(defvar isearch-lazy-highlight-lax-whitespace nil)
+(defvar isearch-lazy-highlight-regexp-lax-whitespace nil)
 (defvar isearch-lazy-highlight-word nil)
 (defvar isearch-lazy-highlight-forward nil)
 (defvar isearch-lazy-highlight-error nil)
@@ -2847,6 +2910,10 @@ by other Emacs features."
                           isearch-regexp))
                  (not (eq isearch-lazy-highlight-word
                           isearch-word))
+                 (not (eq isearch-lazy-highlight-lax-whitespace
+                          isearch-lax-whitespace))
+                 (not (eq isearch-lazy-highlight-regexp-lax-whitespace
+                          isearch-regexp-lax-whitespace))
                  (not (= (window-start)
                          isearch-lazy-highlight-window-start))
                  (not (= (window-end)   ; Window may have been split/joined.
@@ -2873,7 +2940,8 @@ by other Emacs features."
           isearch-lazy-highlight-last-string  isearch-string
           isearch-lazy-highlight-case-fold-search isearch-case-fold-search
           isearch-lazy-highlight-regexp       isearch-regexp
-          isearch-lazy-highlight-space-regexp (isearch-whitespace-regexp)
+          isearch-lazy-highlight-lax-whitespace   isearch-lax-whitespace
+          isearch-lazy-highlight-regexp-lax-whitespace isearch-regexp-lax-whitespace
           isearch-lazy-highlight-word         isearch-word
           isearch-lazy-highlight-forward      isearch-forward)
       (unless (equal isearch-string "")
@@ -2887,7 +2955,6 @@ Attempt to do the search exactly the way the pending Isearch would."
   (condition-case nil
       (let ((case-fold-search isearch-lazy-highlight-case-fold-search)
             (isearch-regexp isearch-lazy-highlight-regexp)
-            (search-spaces-regexp isearch-lazy-highlight-space-regexp)
             (isearch-word isearch-lazy-highlight-word)
             (search-invisible nil)      ; don't match invisible text
             (retry t)