Duplicate lines in region "in-place" - emacs

I am trying to code an elisp function which takes all (non-empty) lines in the current region and duplicates these lines in-place. I'll give you an example:
This input:
Line1
Line2
Line3
Becomes
Line1
Line1
Line2
Line2
Line3
Line3
If there were empty lines, they would remain in place and should not be duplicated. If have coded the following function:
(defun duplicate-lines-in-region (beg end)
"Duplicates the lines in the current region \"in-place\"."
(interactive "r")
(if (use-region-p)
(let* ((text (buffer-substring-no-properties (region-beginning) (region-end)))
(lines (split-string text "\n" t))
(num-lines (length lines))
(current-line 0)
(end-pos 0))
(save-excursion
(goto-char (region-beginning))
(while (< current-line num-lines)
(end-of-line)
(insert "\n")
(insert (nth current-line lines))
(next-line)
(setq current-line (+ current-line 1))
(setq end-pos (point))))
(goto-char end-pos))
(error "No active region!")))
However, this function has some (at least two) bugs:
Empty lines are not ignored but rather completely destroy the output (lines are inserted in the wrong places).
The first line that is inserted is always inserted with the wrong indentation (at column zero), all other lines are inserted at the right indentation.
I'm kinda stuck with advancing the function to a more useful state. Also, I highly doubt that my approach is particularly efficient/well-written... maybe some elisp-guru knows a more straightforward approach that can be used to work on each line in a region individually...

This might be cheating, but you could just use a regex replace to match non-blank lines and replace them with the captured line and a duplicate. Use M-x replace-regexp with a region highlighted, and the following arguments:
Replace regexp: \(.+\)$
With: \&^J\&
Note, in the above, ^J represents a newline/quoted enter key, C-q C-j.
To translate this into elisp, you just need to make sure to escape the backslashes and parentheses:
(defun duplicate-lines-in-region (beg end)
(interactive "*r")
(replace-regexp "\\(.+\\)$" "\\&\n\\&" nil beg end))

Related

Split lines of current paragraph in Emacs

I want to add a function (para2lines) to Emacs by which I can split the current paragraph into its sentences and print them line by line in a separate buffer. Following is code in Racket/Scheme:
(define (p2l paraString)
(define lst (string-split paraString ". "))
(for ((i lst))
(displayln i)))
Testing:
(p2l "This is a test. For checking only. Only three lines.")
Output:
This is a test.
For checking only.
Only three lines.
In Emacs Lisp, I could manage following code:
(defun pl (ss)
(interactive)
(let ((lst (split-string (ss))))
(while lst
(print (pop lst)))))
But I do not know how to get the text from the paragraph with current position. How can I correct this function?
Edit: basically, I want to read it as separate lines but want to save it as paragraph.
Here's an example that might help you on your way. It will do your conversion to the current paragraph (i.e. where the cursor is positioned), rather than to a new buffer. You could modify this to pass a string to your function if that's what you require.
(defun p2l ()
"Format current paragraph into single lines."
(interactive "*")
(save-excursion
(forward-paragraph)
(let ((foo (point)))
(backward-paragraph)
(replace-regexp "\n" " " nil (1+ (point)) foo)
(backward-paragraph)
(replace-regexp "\\. ?" ".\n" nil (point) foo))))
I would just run Emacs commands or write a macro to convert a paragraph to single-sentence lines, but maybe you are really just wanting to read wrapped paragraphs as lines, thus the need to have an Emacs command.
Here's something that will grab the current paragraph, insert a new buffer *Lines*, and then convert sentences to lines.
(defun para-lines ()
"Split sentences of paragraph to lines in new buffer."
(interactive)
;; Move the paragraph to a new buffer.
(let ((b (generate-new-buffer "*Lines*")))
(with-output-to-temp-buffer b
(let ((beg (save-excursion (forward-paragraph -1) (point)))
(end (save-excursion (forward-paragraph +1) (point))))
(princ (buffer-substring-no-properties beg end))))
;; Switch to new buffer
(with-current-buffer b
;; Since the name starts with "*", shut off Help Mode
(fundamental-mode)
;; Make sure buffer is writable
(setq buffer-read-only nil)
;; From the start of the buffer
(goto-char (point-min))
;; While not at the end of the buffer
(while (< (point) (point-max))
(forward-sentence 1)
;; Delete spaces between sentences before making new new line
(delete-horizontal-space)
;; Don't add a new line, if already at the end of the line
(unless (= (line-end-position) (point))
(newline))))))
To avoid using forward-sentence, and just use a regular expression, use re-search-forward. For instance, to match semi-colons as well as periods.
(defun para-lines ()
"Split sentences of paragraph to lines in new buffer."
(interactive)
;; Move the paragraph to a new buffer.
(let ((b (generate-new-buffer "*Lines*")))
(with-output-to-temp-buffer b
(let ((beg (save-excursion (forward-paragraph -1) (point)))
(end (save-excursion (forward-paragraph +1) (point))))
(princ (buffer-substring-no-properties beg end))))
;; Switch to new buffer
(with-current-buffer b
;; Since the name starts with "*", shut off Help Mode
(fundamental-mode)
;; Make sure buffer is writable
(setq buffer-read-only nil)
;; From the start of the buffer
(goto-char (point-min))
;; While not at the end of the buffer
(while (< (point) (point-max))
(re-search-forward "[.;]\\s-+" nil t)
;; Delete spaces between sentences before making new new line
(delete-horizontal-space)
;; Don't add a new line, if already at the end of the line
(unless (= (line-end-position) (point))
(newline))))))

Emacs24 and python-mode: indention in docstrings

I have the following code/text:
def f():
"""
Return nothing.
.. NOTE::
First note line
second note line
In Emacs23 (23.4.1) I was able to press TAB in the last line ("second note line"; nomatter how this line was indented) and it was aligned correctly like this:
def f():
"""
Return nothing.
.. NOTE::
First note line
second note line
I.e., it uses the previous line and indents the following line in the same way.
Now in Emacs24 (24.3.1) this does not work anymore and it is aligned like this:
def f():
"""
Return nothing.
.. NOTE::
First note line
second note line
I.e. it aligns the multi-line string block, but does not depend on the previous line.
It affects only docstrings; code is indented as I want. I am using python-mode. How can I change this, so that pressing TAB aligns the block correctly?
Python mode has changed quite a bit between Emacs 23 and 24. There is no configuration that would allow you to do what you want.
But, Emacs is quite flexible and you can advise the (python-indent-context) function to make it return a different result that will lead to the behavior you want. The function (python-indent-context) returns a character at which the indentation is measured and used for indenting the current line. By default, when inside a string, it returns the point where the beginning of the string resides. Thus, your line will be indented to the indentation of the start of the string. We can easily modify it to return a point in the previous non-empty line instead, for instance like this:
(defun python-fake-indent-context (orig-fun &rest args)
(let ((res (apply orig-fun args))) ; Get the original result
(pcase res
(`(:inside-string . ,start) ; When inside a string
`(:inside-string . ,(save-excursion ; Find a point in previous non-empty line
(beginning-of-line)
(backward-sexp)
(point))))
(_ res)))) ; Otherwise, return the result as is
;; Add the advice
(advice-add 'python-indent-context :around #'python-fake-indent-context)
The same effect can be achieved using the old defadvice for older Emacs:
(defadvice python-indent-context (after python-fake-indent-context)
(pcase ad-return-value
(`(:inside-string . ,start) ; When inside a string
(setq ad-return-value ; Set return value
`(:inside-string . ,(save-excursion ; Find a point in previous non-empty line
(beginning-of-line)
(backward-sexp)
(point)))))))
(ad-activate 'python-indent-context)
What about editing the section de-stringified in a separate buffer? That would allow python-mode with all its facilities.
Here a first draft - original string will be stored in kill-ring:
(defun temp-edit-docstring ()
"Edit docstring in python-mode. "
(interactive "*")
(let ((orig (point))
(pps (parse-partial-sexp (point-min) (point))))
(when (nth 3 pps)
(let* (;; relative position in string
(relpos (- orig (+ 2 (nth 8 pps))))
(beg (progn (goto-char (nth 8 pps))
(skip-chars-forward (char-to-string (char-after)))(push-mark)(point)))
(end (progn (goto-char (nth 8 pps))
(forward-sexp)
(skip-chars-backward (char-to-string (char-before)))
(point)))
(docstring (buffer-substring beg end)))
(kill-region beg end)
(set-buffer (get-buffer-create "Edit docstring"))
(erase-buffer)
(switch-to-buffer (current-buffer))
(insert docstring)
(python-mode)
(goto-char relpos)))))
When ready, copy the contents back into original buffer.
Which remains to be implemented still.

Emacs insert centered comment block

I would like to create a macro for emacs that will insert a latex comment block with some centerd text like:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Comment 1 %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% Comment 2 Commenttext 3 %%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Is this possible in emacs-lisp?
Emacs comes with the command comment-box for this purpose. It produces centered comment boxes, although the width of the box varies depending on the content. E.g., with the region set around the following line:
This is a comment
when you call M-x comment-box the text is transformed to:
;;;;;;;;;;;;;;;;;;;;;;;
;; This is a comment ;;
;;;;;;;;;;;;;;;;;;;;;;;
I use a modifed version that places the comment box around the current line if the region isn't active, and then steps out of the comment afterwards. It also temporarily reduces the fill-column, so the comment box is not wider than your longest line:
(defun ty-box-comment (beg end &optional arg)
(interactive "*r\np")
(when (not (region-active-p))
(setq beg (point-at-bol))
(setq end (point-at-eol)))
(let ((fill-column (- fill-column 6)))
(fill-region beg end))
(comment-box beg end arg)
(ty-move-point-forward-out-of-comment))
(defun ty-point-is-in-comment-p ()
"t if point is in comment or at the beginning of a commented line, otherwise nil"
(or (nth 4 (syntax-ppss))
(looking-at "^\\s *\\s<")))
(defun ty-move-point-forward-out-of-comment ()
"Move point forward until it's no longer in a comment"
(while (ty-point-is-in-comment-p)
(forward-char)))
Here's a yasnippet that you can use:
# -*- mode: snippet -*-
# name: huge_comment
# key: hc
# --
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%${1:$(repeat-char (- 33 (/ (length yas-text) 2)) " ")}$1${1:$(repeat-char (- 74 (length yas-text) (- 33 (/ (length yas-text) 2))) " ")}%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
$0
How to use it: type hc, call yas-expand and start typing the text. It will re-center itself
automatically.
This snippet will work from latex-mode or text-mode. I've noticed however a bug that
messes up the cursor position if you're using AUCTeX. In that case, you can momentarily switch
to text-mode.
The question was whether it is possible in emacs-lisp. Yes it is. There are several ways to do it.
I will show one way where you can also comment several lines of text.
Maybe, in the first line there is the title of the part of text and in the second one there is the author of this part.
A better way would be to advice LaTeX-indent-line function. This way you could edit the comment text and re-indent. When I find time I will show you also this variant.
Usage: Write your comment as clear text. Mark text as region with the mouse and then run the following command.
(defun LaTeX-centered-comment (b e)
"Convert region into centered comment."
(interactive "r")
(let* ((n (count-lines b e)))
(goto-char b)
(beginning-of-line)
(insert-char ?% fill-column)
(insert ?\n)
(setq b (point))
(center-line n)
(goto-char b)
(loop for i from 1 upto n do
(replace-region (point) (+ (point) 3) "%%%")
(end-of-line)
(insert-char ?\ (max 0 (- fill-column (- (point) (line-beginning-position)) 3)))
(insert "%%%")
(forward-line))
(insert-char ?% fill-column)
(insert ?\n)
))

Emacs: capture paragraphs and act on each

Quite often I need to capture some paragraphs in a region with regexp - and then act on each paragraph.
For example consider a problem of recovering a numberd list:
1. Some text with a blank
line. I want not to have that line break
2. Some more text. Also - with
a line break.
3. I want to have a defun which
will capture each numbered entry
and then join it
I want to write a defun which will make the previous text like that:
1. Some text with a blank line. I want not to have that line break
2. Some more text. Also - with a line break.
3. I want to have a defun which will capture each numbered entry and then join it
Here's my best try for now:
(defun joining-lines (start end)
(interactive "r")
(save-restriction
(narrow-to-region start end)
(goto-char (point-min))
(while (search-forward-regexp "\\([[:digit:]]\\. \\)\\(\\[^[:digit:]\\].*?\\)" nil t)
(replace-match "\\1\\,(replace-regexp-in-string " ;; here's a line break
" " " (match-string 2))" t nil))
)
)
It neither work - nor give an error.
Actually it would be better to have a separate defun to act on a string. This way it will be easy to expand the code to have multiple substitutions on the replace-match.
There are two issues with your code:
A period in a regexp matches "anything except newline," so your .*? will never include a newline character.
The \,(...) regexp replacement construct is only available interactively. If issue #1 were resolved, you'd get an error (error "Invalid use of '\\' in replacement text"). Programmatically, you have to write the code yourself, eg: (replace-match (concat (match-string 1) (replace-regexp-in-string "\n" " " (match-string 2)))).
I think you'd be better off not relying on regexps to do the heavy lifting here. This works for me:
(defun massage-list (start end)
(interactive "r")
(save-excursion
(save-restriction
(narrow-to-region start end)
(goto-char start)
(while (progn (forward-line) (= (point) (line-beginning-position)))
(when (not (looking-at "^[[:digit:]]+\\."))
(delete-indentation)
(beginning-of-line))))))
Try something like this code. It's not the shortest possible but rather something straigthforward.
(defun joining-lines(start end)
(interactive "r")
(let ((newline-string "~~~"))
(save-restriction
(narrow-to-region start end)
(mark-whole-buffer)
(replace-string "\n" newline-string)
(goto-char start)
(while (re-search-forward (concat newline-string "\\([[:digit:]]+. \\)") nil t)
(replace-match "\n\\1" nil nil))
(mark-whole-buffer)
(replace-string newline-string " "))))
Here's a solution using an external defun:
(defun capturing-paragraphs (start end)
(interactive "r")
(save-restriction
(narrow-to-region start end)
(goto-char (point-min))
(while (search-forward-regexp "^\\(^[[:digit:]]+\\.[^[:digit:]]+$\\)" nil t) (replace-match (multiple-find-replace-in-match) t nil))))
(defun multiple-find-replace-in-match ()
"Returns a string based on current regex match."
(let (matchedText newText)
(setq matchedText
(buffer-substring-no-properties
(match-beginning 1) (match-end 1)))
(setq newText
(replace-regexp-in-string "\n" "" matchedText) )
newText))
it works only if there's no figures in the text. But this solution is straighforward to expand - to add new replacements on a matched string.

Fix undesirable EMACS tabbing behavior in ESS/Stata

ESS/Stata mode in emacs incorrectly indents lines that follow lines ending in operators. It seems to incorrectly interpret these lines as multiline commands.
For example:
gen foo = 1
/* generate another variable */
gen bar = 1
The line "gen bar = 1" should not be indented. It looks like EMACS interprets the trailing slash in the comment as an operator, and thinks this line of code spans two lines.
In fact, multiline commands in stata have 3 trailing slashes, and newlines without 3 trailing slashes indicate the end of a statement. e.g. the following indentation would be correct:
gen bar = 1
gen ///
foo = 1
Is there something I can put in my .emacs to correct this behavior? I don't want to give up automatic tabbing completely - it works very well for everything except comments that /* look like this */.
Thanks,
Pnj
You're right, ESS interprets the trailing / as an indication of line continuation. This is hard-coded into the function ess-continued-statement-p, so to modify the behaviour you have to rewrite the code. The following code (in your .emacs) works for your examples.
(eval-after-load 'ess-mode
'(defun ess-continued-statement-p ()
"this is modified code"
(let ((eol (point)))
(save-excursion
(cond ((memq (preceding-char) '(nil ?\, ?\; ?\} ?\{ ?\]))
nil)
;; ((bolp))
((= (preceding-char) ?\))
(forward-sexp -2)
(looking-at "if\\b[ \t]*(\\|function\\b[ \t]*(\\|for\\b[ \t]*(\\|while\\b[ \t]*("))
((progn (forward-sexp -1)
(and (looking-at "else\\b\\|repeat\\b")
(not (looking-at "else\\s_\\|repeat\\s_"))))
(skip-chars-backward " \t")
(or (bolp)
(= (preceding-char) ?\;)))
(t
(progn (goto-char eol)
(skip-chars-backward " \t")
(or (and (> (current-column) 1)
(save-excursion (backward-char 1)
;;;; Modified code starts here: ;;;;
(or (looking-at "[-:+*><=]")
(and (looking-at "/")
(save-excursion (backward-char 1)
(not (looking-at "*")))))))
;;;; End of modified code ;;;;
(and (> (current-column) 3)
(progn (backward-char 3)
(looking-at "%[^ \t]%")))))))))))