Delete spaces in beginning of kill-ring in Emacs - emacs

I would like to insert the contents of the kill-ring at the point using (yank), however if there is white space in the beginning of the yanked text, it should be deleted before insertion.
How can this be done?
(I have looked at save-excursion and re-search-backward but could not get it to work)..

You could try
(defun my-yank ()
(interactive)
(let ((start (point)))
(call-interactively 'yank)
(let ((end (point)))
(save-excursion
(goto-char start)
(delete-region (point)
(progn (skip-chars-forward " \t" end) (point)))))))

Here is a possible solution
(defun yank-no-spaces (&optional arg)
(interactive "*P")
(yank arg)
(save-restriction
(save-excursion
(narrow-to-region (point) (mark))
(goto-char (point-min))
(just-one-space 0))))

Related

Transpose non-word function arguments?

When writing Haskell code in Emacs, I often end up in situations where I'd like to change:
(foo, [])
into
([], foo)
If Emacs recognized [] as a word, then I could just use M-t to transpose-words and switch them. Is it possible to do this in a way that doesn't break other functionality?
You want C-M-t, which runs the command transpose-sexps.
There are quite a few commands starting with C-M- that run s-exp commands instead of similar word based commands , such as C-M-f/C-M-b, forward/backward by s-exp.
Also, there's an Emacs Stack Exchange over at emacs.SE.
(defun my-transpose-function-args ()
"Assumes to be called between arguments. "
(interactive "*")
(let* ((orig (point))
(end1 (progn (skip-chars-backward " \t\r\n\f,")
(point)))
(beg1
(progn
(skip-chars-backward "^ \t\r\n\f,(")
(point)))
(string1 (buffer-substring beg1 end1))
(beg2 (copy-marker
(progn (goto-char orig)
(skip-chars-forward " \t\r\n\f")
(point))))
(end2 (copy-marker
(progn (skip-chars-forward "^ \t\r\n\f,)")
(point))))
(string2 (buffer-substring beg2 end2)))
(goto-char beg1)
(delete-region beg1 end1)
(insert string2)
(goto-char beg2)
(delete-region beg2 end2)
(insert string1)))

Moving lines internally in emacs 24.4

I have this snippet of code in my .emacs file that should move lines of code up or down. This works fine on 24.3.1 but not fully on 24.4.
moving lines down work, as the line would be swapped with the bottom line and the "cursor" would move as well.
Moving the line up however, it will swap but the cursor stay on the same line without moving up along with the line.
Is there a reason for that?
;; Moving a line up or down
(defun move-text-internal (arg)
(cond
((and mark-active transient-mark-mode)
(if (> (point) (mark))
(exchange-point-and-mark))
(let ((column (current-column))
(text (delete-and-extract-region (point) (mark))))
(forward-line arg)
(move-to-column column t)
(set-mark (point))
(insert text)
(exchange-point-and-mark)
(setq deactivate-mark nil)))
(t
(let ((column (current-column)))
(beginning-of-line)
(when (or (> arg 0) (not (bobp)))
(forward-line)
(when (or (< arg 0) (not (eobp)))
(transpose-lines arg))
(forward-line -1))
(move-to-column column t)))))
(defun move-text-down (arg)
"Move region (transient-mark-mode active) or current line
arg lines down."
(interactive "*p")
(move-text-internal arg))
;(global-set-key [M-S-down] 'move-text-down)
(global-set-key [A-M-down] 'move-text-down)
(defun move-text-up (arg)
"Move region (transient-mark-mode active) or current line
arg lines up."
(interactive "*p")
(move-text-internal (- arg)))
;(global-set-key [M-S-up] 'move-text-up)
(global-set-key [A-M-up] 'move-text-up)

How to test for a syntax condition without moving the cursor?

I have been unable to come up with a method to test for a syntax condition without moving the cursor -- e.g., skip-syntax-forward and skip-chars-forward both move the cursor in order to return t or a positive value. How can I return t or nil without moving the cursor?
(defun lawlist-kill-word ()
"Mark word / symbol + whitespace to the right of the cursor, and kill same."
(interactive)
(let* (
(symbol-regexp "\\s.\\|\\s_")
(word-regexp "\\sw"))
(modify-syntax-entry ?' "_") ;; apostrophe = symbol constituent
(cond
((< 0 (skip-syntax-forward "_."))
(let ((end (point)))
(set-mark end)
(while (looking-back symbol-regexp)
(backward-char))
(let ((beg (point)))
(delete-region beg end)
(setq beg (point))
(cond
((skip-chars-forward " \t")
(setq end (point))
(set-mark end)
(delete-region beg end))))))
((< 0 (skip-syntax-forward "w"))
(let ((end (point)))
(set-mark end)
(while (looking-back word-regexp)
(backward-char))
(let ((beg (point)))
(delete-region beg end)
(setq beg (point))
(cond
((skip-chars-forward " \t")
(setq end (point))
(set-mark end)
(delete-region beg end))))))
(t
(let ((beg (point)))
(set-mark beg)
(skip-chars-forward " \t")
(let ((end (point)))
(delete-region beg end)))
(deactivate-mark)))
(modify-syntax-entry ?' "w") )) ;; apostrophe = word constituent
EDIT:  lawlist-kill-word is a work in progress -- any updates to this function will be posted to a thread related to that issue -- i.e.,: Emacs: delete whitespaces or a word
As #Tobias said: wrap cursor movements in save-excursion. Save any values you want (e.g., of (point)) in variables and return them as needed.
E.g., if you want the position four lines ahead, do something like this:
(let ((posn (save-excursion (forward-line 4) (point))))
posn)

Define a copy-section command in Emacs

I would like to set up a command that put the content of the lines between two § characters without moving the point (not including the lines containg the §).
Here is my current attempt
(defun copy-section ()
"Copy current section, that is lines between two §."
(interactive)
(save-excursion
(when (not (search-backward-regexp "§" nil t))
(goto-char (point-min)) )
(forward-line 1)
(when (not (search-forward-regexp "§" nil t))
(goto-char (point-max)) )
(move-beginning-of-line nil)
(kill-ring-save (mark) (point)) ) )
It works well but the remarks in the documentation about moving around the mark being bad style make me think taht there is a better way to achieve the same result.
Does saving position into variable (which I do not know how to do it) allows for a cleaner function.
Part of the code above comes from ergoemacs.
No "regexp" form needed as only a char is looked for
(defun copy-section ()
"Copy current section, that is lines between two §."
(interactive)
(save-excursion
(let* ((start (and (search-backward "§" nil t)
(forward-line 1)
(point)))
(end (progn (and start (search-forward "§" nil t))
(forward-line -1)
(end-of-line)
(point))))
(and start end (kill-new (buffer-substring-no-properties start end))))))
This version saves the beginning and end of your section in temporary local variables, and doesn't use the mark at all:
(defun copy-section ()
"Copy current page as defined by form feed characters."
(interactive)
(let (start end)
(save-excursion
(when (not (search-backward-regexp "§" nil t))
(goto-char (point-min)) )
(forward-line 1)
(setq start (point))
(when (not (search-forward-regexp "§" nil t))
(goto-char (point-max)) )
(move-beginning-of-line nil)
(setq end (point))
(kill-ring-save start end))))

How to avoid line breaks within |...| in Emacs

In Emacs, how can I avoid line breaks within |...| when using M-q (fill-paragraph)?
In https://groups.google.com/forum/?fromgroups#!searchin/gnu.emacs.help/fill-nobreak-predicate/gnu.emacs.help/qNuZZjQnsww/99oJ1fb4OSUJ I found the following solution for [[...]], but it doesn't work when the open and close delimiters are the same:
(defun fill-open-link-nobreak-p ()
"Don't break a line after an unclosed \"[[link \"."
(save-excursion
(skip-chars-backward " ")
(let ((opoint (point))
spoint inside)
(save-excursion
(beginning-of-line)
(setq spoint (point)))
(when (re-search-backward "\\[\\[" spoint t)
;; (message "found") (sit-for 2)
(unless (re-search-forward "\\]\\]" opoint t)
(setq inside t)))
inside)))
(add-to-list 'fill-nobreak-predicate 'fill-open-link-nobreak-p)
This seems to do the trick:
(defun odd-number-of-pipes-this-paragraph-so-far ()
(oddp (how-many "|" (save-excursion (backward-paragraph) (point)) (point))))
(add-to-list 'fill-nobreak-predicate 'odd-number-of-pipes-this-paragraph-so-far)