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[PATCHv2] Add cycle-spacing command.
[PATCHv2] Add cycle-spacing command.
Mon, 10 Dec 2012 15:57:45 +0100
From: Michal Nazarewicz <address@hidden>
This commit adds a cycle-spacing command which is, in a sense,
generalisation of the just-on-space command. When run continuously,
it cycles between having only one space, having no spaces and original
etc/NEWS | 5 +++
lisp/ChangeLog | 4 ++
lisp/simple.el | 86 ++++++++++++++++++++++++++++++++++++++++++++++----------
3 files changed, 80 insertions(+), 15 deletions(-)
v2: changed name to cycle-spacing
diff --git a/etc/NEWS b/etc/NEWS
index 77e7e47..8112573 100644
@@ -92,6 +92,11 @@ when its arg ADJACENT is non-nil (when called interactively
with C-u C-u)
it works like the utility `uniq'. Otherwise by default it deletes
duplicate lines everywhere in the region without regard to adjacency.
+** New `cycle-spacing' command allows cycling between having just one
+space, no spaces, or reverting to the original spacing. Like
+`just-one-space' command it can handle or ignore newlines and use
+leave different number of spaces.
*** New connection method "adb", which allows to access Android
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 7f05613..7ac779a 100644
@@ -1,3 +1,7 @@
+2012-12-10 Michal Nazarewicz <address@hidden>
+ * simple.el: Add cycle-spacing command.
2012-12-10 Eli Zaretskii <address@hidden>
* subr.el (w32notify-handle-event): New function.
diff --git a/lisp/simple.el b/lisp/simple.el
index 78b7657..dcb8cf7 100644
@@ -742,25 +742,81 @@ If BACKWARD-ONLY is non-nil, only delete them before
(skip-chars-backward " \t")
(constrain-to-field nil orig-pos)))))
+(defvar cycle-spacing--context nil
+ "Store context used in consecutive calls to `cycle-spacing' command.
+The first time this function is run, it saves the original point
+position and original spacing around the point in this
+(defun cycle-spacing (&optional n preserve-nl-back single-shot)
+ "Manipulate spaces around the point in a smart way.
+When run as an interactive command, the first time it's called
+in a sequence, deletes all spaces and tabs around point leaving
+one (or N spaces). If this does not change content of the
+buffer, skips to the second step:
+When run for the second time in a sequence, deletes all the
+spaces it has previously inserted.
+When run for the third time, returns the whitespace and point in
+a state encountered when it had been run for the first time.
+For example, if buffer contains \"foo ^ bar\" with \"^\" donating the
+point, calling `cycle-spacing' command will replace two spaces with
+a single space, calling it again immediately after, will remove all
+spaces, and calling it for the third time will bring two spaces back
+If N is negative, delete newlines as well. However, if
+PRESERVE-NL-BACK is t new line characters prior to the point
+won't be removed.
+If SINGLE-SHOT is non-nil, will only perform the first step. In
+other words, it will work just like `just-on-space' command."
+ (interactive "*p")
+ (let ((orig-pos (point))
+ (skip-characters (if (and n (< n 0)) " \t\n\r" " \t"))
+ (n (abs (or n 1))))
+ (skip-chars-backward (if preserve-nl-back " \t" skip-characters))
+ (constrain-to-field nil orig-pos)
+ ;; Command run for the first time or single-shot is non-nil
+ ((or single-shot
+ (not (equal last-command this-command))
+ (not cycle-spacing--context))
+ (let* ((start (point))
+ (n (- n (skip-chars-forward " " (+ n (point)))))
+ (mid (point))
+ (end (progn
+ (skip-chars-forward skip-characters)
+ (constrain-to-field nil orig-pos t))))
+ (setq cycle-spacing--context ;; Save for later
+ ;; Special handling for case where there was no space at all
+ (unless (= start end)
+ (cons orig-pos (buffer-substring start (point)))))
+ ;; If this run causes no change in buffer content, delete all spaces,
+ ;; otherwise delete all excees spaces.
+ (delete-region (if (and (not single-shot) (zerop n) (= mid end))
+ start mid) end)
+ (dotimes (_ n)
+ (insert ?\s))))
+ ;; Command run for the second time
+ ((not (equal orig-pos (point)))
+ (delete-region (point) orig-pos))
+ ;; Command run for the third time
+ (insert (cdr cycle-spacing--context))
+ (goto-char (car cycle-spacing--context))
+ (setq cycle-spacing--context nil)))))
(defun just-one-space (&optional n)
"Delete all spaces and tabs around point, leaving one space (or N spaces).
If N is negative, delete newlines as well, leaving -N spaces."
- (unless n (setq n 1))
- (let ((orig-pos (point))
- (skip-characters (if (< n 0) " \t\n\r" " \t"))
- (n (abs n)))
- (skip-chars-backward skip-characters)
- (constrain-to-field nil orig-pos)
- (dotimes (i n)
- (if (= (following-char) ?\s)
- (forward-char 1)
- (insert ?\s)))
- (skip-chars-forward skip-characters)
- (constrain-to-field nil orig-pos t)))))
+ (cycle-spacing n nil t))
(defun beginning-of-buffer (&optional arg)
"Move point to the beginning of the buffer.