Indent multiple lines in Emacs - emacs

I am looking for shortcuts or functions to add one tab to all lines in the selection. Also how to reduce one tab to all lines in the selection?
There are multiple references for this. But I could not find one that mimics use of tab and shift-tab on selected text as in regular editors like geany. There one can select multiple lines and then use tab or shift-tab to move text left and right till one finds it best.
I found C-x tab <left> or <right> : this moves all lines in the selection to left or right one space at a time. C-5 C-x tab move it 5 spaces but then stops. But I want these lines to move tab spaces at a time while keeping the selection so that I can repeat or undo the process. How can I do that?
Basically, I need a function which I can call after selecting some lines. It should:
Detect the selected lines
On pressing a key (say 1 on num pad) it should move selected text to left by 5 spaces (and keeping the selection)
On pressing another key (say 3 on num pad), it should move selected text to right by 5 spaces (and keep selection)
The function should end on pressing ENTER.
Can above ability be added to C-x tab shortcut, which works exactly like that (with left and right keys) but it moves selected text only one space at a time.

I am looking for shortcuts or functions to add one tab to all lines in the selection.
First select a region.
C-SPC [set-mark-command]
Select region of lines, with the mark at beginning of first line and the point at the beginning of last last line (or vice versa), and then
C-x r t [string-rectangle]
C-q TAB [quoted-insert]
I found C-x TAB <left> or <right>: this moves all lines in the selection to left or right one space at a time.
Did you see on option for hitting S-<left> and S-<right>? That should do it for you, Shift + Right, perhaps only depending on what mode you are in and whether indent-tabs-mode is enabled.

If you use evil-mode, you have the key > that indents the current line or the selection to one level, according to the mode. I don't know how to make it insert tabs. By a quick look at the documentation by keywords (C-h d indent tab RET) it looks like we have the variable indent-tabs-mode:
indentation can insert tabs if this is non nil
More generally, this doesn't seem to suit your requirements but nearly in that it helps on indenting multiple lines in a row and repeatedly: indent-tools (on melpa) (my toy). It's meant for indentation-based files (so yaml, python,…) and it gives an hydra (which helps to repeat the actions) with the commands: indent or de-indent the current block of indentation, the paragraph, etc, and the same to comment, delete, fold, and move around blocks of indentation.

Related

De-indent region as rigid block

I want to move a region leftwards by one tab stop, as a rigid block (not changing indentation of internal lines).
Here's the quote from the relevant documentation, but I don't understand:
C-x TAB This command is used to change the indentation of all lines
that begin in the region, moving the affected lines as a “rigid” unit.
If called with no argument, the command activates a transient mode for
adjusting the indentation of the affected lines interactively. While
this transient mode is active, typing LEFT or RIGHT indents leftward
and rightward, respectively, by one space. You can also type S-LEFT or
S-RIGHT to indent leftward or rightward to the next tab stop (see Tab
Stops). Typing any other key disables the transient mode, and resumes
normal editing.
I'm not seeing a transient mode. How do I move a region to the previous tab stop?
Related answer, to un-indent by 4 spaces
This behaviour, of a transient mode, was introduced in Emacs 24.4. In this case the submitter was running 24.3.
On Emacs 24.3, indent-rigidly cannot shift forward or back "to the nearest tab stop". Instead it may only be used to shift by a given number of characters.
For example:
to shift the region to the left by 7 characters use C-u - 7 C-x <tab>
to shift the region to the right by 3 characters use C-u 3 C-x <tab>
I think your goal can also be achieved by 'rectangle operations'.
To move a text block to left by one tab stop, you can just delete a column of tabs in the left, then the text block will be moved automatically to left by the length of what have been deleted.
The steps to do so:
select the content you want to delete as region. Be aware of that the start point and end point of the region will be the rectangle's two vertexes.
issue \C-x r d, or M-x delete-rectangle.
And to move a text block to right by one tab stop, you can just insert a column of tabs before the text block.
same as above one. But now the rectangle's width should be 0 (that is, the start point and end point of the region is on the same column).
issue \C-x r t <TAB>, or M-x string-rectangle. Here <TAB> is the contents you want to insert, it can be anything else.

Swapping 2 columns with Emacs

I have 2 columns, separated by comma. How can I swap those columns with Emacs?
I have the following:
column 1,column2
x1,x2
y1,y2
f1,f2
and I want it like this:
column2,column 1
x2,x1
y2,y1
f2,f1
Use M-x query-replace-regexp and then:
\(.+\),\(.+\)
as replace regexp and
\2,\1
for replacement.
In Emacs, you need to escape grouping parentheses with \. So, above regexp would be usually written as
(.+),(.+)
which means that you want everything before comma in first group and everything after comma in second group.
\2,\1
means: write second group, then comma, then first group.
While you can apply techniques given by other people, you can also use the org-mode tables.
Once you convert the data into org-mode table, it is very easy to swap the columns by simple keystrokes. You can have M-x org-mode, select the region then do M-x org-table-convert-region, and then M- on the right most column. I am not sure, how to export the data as CSV, but that should be very easy for you with replace-regexp. This can be helpful: http://www.gnu.org/software/emacs/manual/html_node/org/Tables.html#Tables
Similar to the answer given by #darioo, type the following into the top of your buffer:
(query-replace-regexp "\\(.*?\\),\\(.*\\)" "\\2,\\1")
Then, put your cursor at the end of this line and press ctrl-x, ctrl-e.
You will have an interactive search-and-replace for which you press the space bar to make the change, and press ctrl-g to quit. If you press ! (exclamation mark) then the search will cease being interactive and take place on all matching text.
If you want to reverse the changes then press M-x (usually ESC followed by x) and type undo and press enter.
Emacs has a rectangular selection mode, see for example: http://emacs-fu.blogspot.com/2008/12/working-with-rectangular-selections.html
Even better, if you enable cua-mode, entering Ctrl-Enter will put you in rectangle selection mode that is very easy to use.
http://trey-jackson.blogspot.com/2008/10/emacs-tip-26-cua-mode-specifically.html
Use a macro !
Go to the first line of the buffer
Start recording a macro (F3)
Move to the beginning of the line (^a)
Search for comma (^s ,)
Transpose (M-t)
Move cursor down one line
Stop recording macro (F4)
Select the rest of the lines and:
M-x apply-macro-to-region-lines
UPDATE: This doesn't work properly if you have multiple words in a column. Looking for a more general solution...

Emacs remember text selection

I decided that I was ready to try something new, after a few years of using gEdit for most of my coding needs, and try to learn using Emacs. I knew this would be difficult, as I have heard how complex Emacs can be, but I was lured by its power. The hardest thing has been getting used to writing ELisp in the .emacs file to change things about the editor. I can't currently do it myself, but I have found a few helpful snippets here and there to change some options.
One thing I have been having a lot of problems with is getting Emacs to remember the text I have selected after a command. For instance, I commonly highlight a section of code to mass indent it. However, if I do this in Emacs, it will move the selected text only once before unselecting all of the text. Does anyone know a way around this?
Anyway, I apologize for what seems to me to be an easy question, but after an hour of Google searching and looking around here on SO, I thought it was worth asking. I have a few more questions about Emacs, but I will save them and ask separately after I get this straightened out. Thanks!
UPDATE
A few people have asked about what mod I am using and what type of text I am entering. While I don't know much about Emacs modes, I am editing a pure text file at the moment. Something like this:
Hello, I am a simple text file
that is made up of three separate
lines.
If I highlight all three lines and hit TAB, I get this:
Hello, I am a simple text file
that is made up of three separate
lines.
This is great, however, if I use C-x C-x like some suggest below to reselect the text and hit TAB again, I get this:
Hello, I am a simple text file
that is made up of three separate
lines.
I hope this helps!
FWIW, here is the reason for the behaviour of your newly-added example. (I'm not 'solving' the issue here, but I'm posting it to demystify what you're seeing.)
This was determined with emacs -q which disables my customisations, so the following is default behaviour for emacs 23.2.
You are in text-mode. You should see (Text) or similar in the mode line at the bottom of the screen, and C-h m will tell you (under the list of minor modes) "Text mode: Major mode for editing text written for humans to read." Emacs decides (by way of the auto-mode-alist variable) that it should switch to text-mode if you visit a filename matching certain extensions (such as .txt).
In text-mode pressing TAB with a region highlighted causes indent-according-to-mode to be called on each line of the region in sequence. The slightly convoluted path to finding this out starts at C-h k TAB, which tells us that TAB is bound to indent-for-tab-command, which in this instance calls indent-region -- that function name is not stated explicitly in the help, but can be seen in the code -- which checks the buffer-local indent-region-function variable, which is nil, and: "A value of nil means really run indent-according-to-mode on each line."
indent-according-to-mode checks the indent-line-function variable, which has the buffer-local value indent-relative.
Use C-h f indent-relative RET to see the help for this function. (Read this).
Although you probably won't yet have had the experience to know how to check all that (or necessarily even want to!), and fully understand everything it tells you, this is an example of how the self-documenting aspect of Emacs enables a user to figure out what is going on (which then makes it feasible to change things). I essentially just used C-h k (describe-key), C-h f (describe-function), and C-h v (describe-variable) to follow the documentation. Looking at the source code for indent-for-tab-command was as simple as clicking the file name shown as part of its help page.
I suggest doing the following to help see what is happening when indent-relative runs on each line:
M-x set-variable x-stretch-cursor t
M-x set-variable ruler-mode-show-tab-stops t
M-x ruler-mode
Now for each line in turn, put the cursor at the very start of the line and press TAB. You'll end up with all three lines indented to the first tab-stop ('T' in the ruler).
Now repeat this -- again, ensure you are at the very start of each line, in front of the existing indentation.
The first character of the first line (which is currently a tab) is once again indented to the first tab-stop, as there is no preceding line for it to examine.
Next, the first character of the second line is indented to match the position of the first non-white-space character of the preceding line. Because the first character of the second line is also a tab, the actual text of the second line is pushed one tab further along.
The third line follows suit. Its first tab character is lined up with the first non-white-space character of the second line, with the same relative effect as before, giving you the final state in your example.
To emphasise, note what happens if you now put enter the line "a b c" above the existing lines, then move back to the start of the next line (what was previously the first line) and press TAB. The first tab character will now be indented in line with the 'b'. Provided that the indent-tabs-mode variable is true (meaning you have actual tab characters), then this will have no practical effect on the position of the words in the line, as 'indenting' a tab with spaces will not have an effect until the number of spaces exceeds the width of the tab (but that's another kettle of fish entirely!)
All this really means is that text-mode in Emacs doesn't behave the way you'd like it to in this situation. Other major modes can do completely different things when you press TAB, of course.
As is invariably the case with Emacs, things you don't like can be changed or circumvented with elisp. Some searching (especially at the Emacs Wiki) will frequently turn up useful solutions to problems you encounter.
Try typing C-x C-x after Emacs unselects it.
Then, instead of hitting tab (I never knew that tab does what you said! That's totally whacked.), do M-8 C-x C-i. Pity it's so many keys, but it ought to do what you want -- namely, shove everything over 8 columns. Obviously replace the M-8 with something else if you want some other number of columns.
What I usually do is simply type C-x C-x (exchange-point-and-mark) after a command that deactives the region.
How are you indenting, and in which mode?
The indentation rules in any programming mode should generally just get it right. (If they don't, that's probably more indicative that you want to configure the rules for that mode differently, but I suspect that's a different question which has been asked already).
If you're in text-mode or similar and just using TAB, then I can see the problem.
Note that if you're using indent-rigidly (C-x C-i, or C-x TAB which is the same thing) then you can repeatedly indent the same region simply by repeating the command, even if the highlighting has disappeared from view.
You can also use a prefix arg to indent-rigidly to make it indent many times. e.g. C-u C-u C-x C-i (easier to type than it looks) will indent 16 spaces (4 x 4, as the prefix arg defaults to 4, and it multiplies on each repeat). Similarly, M-8 C-x C-i indents 8 spaces. This is fine in some circumstances, and way too cumbersome in others.
Personally I suggest putting (cua-selection-mode 1) into your .emacs and using that for rigid indentation. Trey Jackson made a handy blog about it. With this, you can C-RET to start rectangle selection, down as many lines as you need, TAB repeatedly to indent the lines, and C-RET to exit the mode.
While the rectangle is active, RET cycles through the corners. For left-hand corners, typing inserts in front. For right-hand corners, typing inserts after. For the single-column rectangle, bottom counts as 'left' and top counts as 'right' for this purpose.
Trey's blog lists all the available features (or look in the source file: cua-base.el)
Be warned that indentation in Emacs is generally an unexpectedly complicated topic.
You can do this with something like the following:
(add-hook 'text-mode-hook (lambda ()
(set (make-local-variable 'indent-region-function)
(lambda (s e)
(indent-rigidly s e tab-width)))))
Then selecting a region and hitting TAB. will indent the region by a tab-width. You can then exchange point and mark with C-x C-x and hit TAB again to repeat.
I do, however, agree with the previous answers that suggest using indent-rigidly directly.

Multiline sentence in emacs

If I have a multiline sentence in Emacs it naturally overflows onto the the following lines. Now, if my cursor is at the beginning of such a sentence and I press the DOWN ARROW key, the cursor is placed at the beginning of the next sentence (which might be at 4-5 lines down), rather than on the next line itself (which other editors do). Same is the behavior of the END and HOME keys.
Is there a way in which I can change this behavior and get the cursor on the next line instead of the next sentence?
I haven't yet tried it myself, but I think what you are asking for is the default behavior for emacs 23. What version are you running?
You might want to check out the page Move By Visible Lines page on the emacswiki.
You might want to try auto-fill-mode or longlines-mode. To get either use M-X then type the command you want. Toggle them off the same way.
If that doesn't work you may want to examine the binding that is being applied to your down arrow. Type C-h k then hit the down arrow key.
It sounds as though the text is wrapping, so by definition (a line being a group of characters separated by a carriage return), it is moving down to the next line.
I agree it is a pain, however a lot of other editors also have this behaviour.
One way is to turn off wrapping:
M-x toggle-truncate-lines
You wont be able to see all of the text in the editor, however it will move down to the next line.

Emacs - Multiple columns one buffer

I'm trying to edit some assembly code which tends to be formatted in long but thin listings. I'd like to be able to use some of the acres of horizontal space I have and see more code on-screen at one time. Is there a method for getting Emacs (or indeed another editor) to show me multiple columns all pointing to the same buffer?
C-x 3 (emacs) and :vsplit (vim) are great for multiple separate views into the code, but I'd like it to flow from one column to the other (like text in a newspaper).
See follow-mode.
Excerpt:
Follow mode is a minor mode that makes two windows, both showing the same buffer, scroll as a single tall “virtual window.” To use Follow mode, go to a frame with just one window, split it into two side-by-side windows using C-x 3, and then type M-x follow-mode. From then on, you can edit the buffer in either of the two windows, or scroll either one; the other window follows it.
In Follow mode, if you move point outside the portion visible in one window and into the portion visible in the other window, that selects the other window—again, treating the two as if they were parts of one large window.
I use this function to invoke follow-mode, although it would need customization for a different screen size:
;;; I want a key to open the current buffer all over the screen.
(defun all-over-the-screen ()
(interactive)
(delete-other-windows)
(split-window-horizontally)
(split-window-horizontally)
(balance-windows)
(follow-mode t))
The "Multipager" plugin for Vim can do this with VIM splits for people who want to get this behavior in Vim.
Get it from Dr. Chip's page: http://mysite.verizon.net/astronaut/vim/index.html#MPAGE
Docs: http://mysite.verizon.net/astronaut/vim/doc/mpage.txt.html
Vim can do this using :vsplit - and you can have the same buffer open in multiple "windows" (which are actually sections within a single "window").
Documentation here
A quick look at the emacs wiki doesn't show a mode like you describe. However, it shouldn't be too hard to write one... You just need to split the window with C-x 3 and move the text in the other window down, and whenever you move the text, do the same to the other window...
Problems may occur when you get to the bottom of the buffer, do you want the cursor to immediately go to the other window at the top?
Hmm, maybe its not that easy. But it should still be doable...
this is the default behaviour of emacs when splitting the window (C-x 3 for vertical split)
you get two columns which both have the current buffer open
Use vertical-split with C-x 3. This will split the current buffer into two columns that you can switch between with C-x o.