Emacs Paredit: how to delete comment semicolons - emacs

Based on How do you comment out all or part of a Lisp s-exp using Paredit? I did C-M-space then M-; and got, as expected, a commented-out S-exp:
;; (when window-system
;; (sr-speedbar-open))
Now how do I delete those semicolons? When I try the obvious (backspace or delete), only one semicolon disappears. I also can't just undo, since I've done other stuff between adding the semicolons and wanting to delete them. I could also turn off paredit for this task, but I'm certain there's a more elegant way.

One thing you could do is re-select the region and then do M-; again, which will un-comment the given region if it's already commented. You could also try this function that I've put together which deletes backwards on a given line, while still preserving delimiters (it's basically a backwards paredit-kill). You'd just navigate to the spot after the comment semicolons and then invoke paredit-backward-delete-line, preferably with whatever key binding that you bound it to (which was <C-backspace> in my above answer).

Related

Emacs lisp, How to make a newline in IELM?

Even the basic things seem to be hidden behind weird shortcut-combinations.
How can I (hopefully without too many c-m-x-c combinations) create a simple new line?
return evaluates the current line
With C-j. That said, if you have paredit enabled, it should do all the newlines you need automatically.
In my case it was M-j.
I'm currently trying out SpaceMacs, not sure if that has anything to do with it.
Even the basic things seem to be hidden behind weird shortcut-combinations.
If you don't want RET to have contextual behaviour, you can M-x customize-option RET ielm-dynamic-return.
How can I ... create a simple new line?
Only a newline? C-qC-j is the normal way to enter a newline in places where RET does something else. (More generally you can use C-q to insert any character that isn't self-inserting for the current buffer.)
If you want newline + indentation (which is what RET does when contextually appropriate), then M-j will do that (noting that if you are in a comment at the time then the new line will also default to a comment).

Is there a way to make regions in term modes respect line wrapping?

When using a term mode derivative (like ansi-term or multi-term), I often want to select a region and copy it someplace else. If that region includes a line which wraps at the edge of the terminal window, pasting that region in another buffer always inserts a hard newline at the place where term wrapped the line. This means I often have to go back and clean up pasted text. Is there a way to avoid doing this? I tried both term-line-mode and term-char-mode; both do the same thing.
I do not want to write a yank hook which strips out all newlines, since I want to preserve existing hard newlines in the original content.
This works for me:
(setq term-suppress-hard-newline t)

How to preserve keybindings when using multi-term.el in line mode?

In emacs (ver. 24.3), I have my forward-paragraph and backward-paragraph mapped to M-p and M-n instead of M-{ and M-}. It is easier for me to remember and use fluidly with C-p and C-n. I've recently started using multi-term to run most of my terminal work. However, when I switch to line-mode my custom bindings for forward and backward paragraph no longer work. It says 'empty input ring'. Oddly when I'm in char-mode, the C-p and C-n do what they are supposed to do (bringing up previous prompt entries), but my paragraph movements work.
So in short, my custom forward and backward paragraph bindings work in char-mode (where I don't really need them), but not in line-mode. Any ideas?
See term-bind-key-alist, which includes C-p, C-n, M-p, and M-n by default. See also these passages from the EmacsWiki page MultiTerm. The second especially seems relevant to your problem. These do not mention term-line-mode or term-char-mode, but I think they might give you a place to start.
Note 1
‘term-unbind-key-list’ is a list of keys which emacs keeps for itself. By default it contains (“C-z” “C-c” “C-x” “C-h” “C-y” “”)
‘term-bind-key-alist’ is a list of keys and functions which you can use, for example to use Emacs style cursor movement to the multi-terminal. The default is long, so I’ll let you look it up yourself.
Note 2
Because C-r is default keystroke for isearch-backward, for avoid conflict with C-r, i binding M-r to send “C-r” character to shell.
You can use option term-bind-key-alist/term-unbind-key-list to binding/unbinding special keystroke in multi-term.el, and don’t use term-mode-hook. ☺ –- AndyStewart
Also, I don't see term-line-mode anywhere in multi-term.el. It looks as if it makes use only of term-char-mode. See, for instance, multi-term-keystroke-setup.

Emacs lisp highlighting

I have wrote simple macro to define interactive function and bind it to key at same time
(That what my previous question related)
The only thing, that annoy me, that it looks ugly without highlighting.
It called such way:
(define-and-bind-command foo "C-x £" (message "Hello world"))
I want define-and-bind-command and foo be highlighted.
Well, to get define-and-bind-command highlighted, I can use wrapper around defmacro,
altho is not so pretty, and I have no idea about foo.
I know it is possible, because argument of require is highlighted with const face.
Or, probably, I am inventing wheel, and there is an another lisp mode with more
advanced highlighting?
highlighting the 'define-and-bind-command' can be achieved very easily using 'font-lock-add-keywords', usage would be
(defun my-elisp-mode-keywords()
(font-lock-add-keywords nil
'(
("\\<\\(define-and-bind-command\\)" . 'font-lock-keyword-face)
)
)
)
Of course you could change the 'font-lock-keyword-face' to any face of your liking or create and use your own face. You can find the name for a face already used very easy by moving the point (cursor) over the font-locked part of text and entering 'describe-face' followed by a return.
Edit2: Oh and of course you need to hook that defun to some hook, for elisp mode that would be:
(add-hook 'emacs-lisp-mode-hook 'my-elisp-mode-keywords)
Highlighting the foo part can be done using a regexp.
Unfortunately I can not yet help you with that part because I'm not sure how to match a regexp containing the 'define-and-bind-command' but highlighting only the word after.
Edit: unless you want to highlight both the 'define-and-bind-command' and the foo part in the same face, then it should be very easy. But I guess you want them to have different faces?
Edit3: Corrected my code, stackoverflow ate some braces before...
Edit4: Okay, I have a solution for matching the second part only, I have not tested it extensively but it seems to work. I have allowed for foo to contains any character but a space (and newline I think), I guess one could restrict that event futher to a-zA-z0-9 and "-", so feel free to change that to your liking. The Code responsible for matching only the foo part is
("\\bdefine-and-bind-command\s\\([^\s]*\\)" 1 'font-lock-function-name-face t)
Insert that in the line after the other font-lock keyword in the above function and you're good to go. The regexp matches 'define-and-bind-command' which must begin a word (that's the \b for) followed by a space and then it returns (font-locks) everything followed until a space exists.
Hope this helps!
font-lock-add-keywords can take a symbol, the mode to which to apply the new keywords. So you could do
(font-lock-add-keywords
'emacs-lisp-mode
'(("\\<\\(define-and-bind-command\\)" . 'font-lock-keyword-face)))
The disadvantage compared to using a function and a hook is that this doesn't work for derived modes; that is, if you have a mode which is derived from emacs-lisp-mode, it will not inherit these keywords.

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.