emacs next-screen-context-lines ignored - emacs

This is probably a very obvious question, but I seem to have missed something. When I first started using emacs about a month ago, pressing C-v would scroll down and leave two line at the top of the screen, à la tutorial. Somewhere along the line I must have upgraded packages, and it now places the cursor at the top of the screen - no context lines.
Running C-u -2 C-v works as expected, so I tried M-x set-variable RET next-screen-context-lines RET 2, which had absolutely no effect. According to C-h v RET next-screen-context-lines, I can set the variable to any positive or negative number I choose, but pressing C-v always results in the cursor moving to the top of the screen and now context lines. Incidentally, M-v has the same problem. I can't find a relevant setting in my .emacs, but I tried mv .emacs .emacs.bak and noticed no difference.
I'm running GNU Emacs 23.4.1 (x86_64-pc-linux-gnu, GTK+ Version 2.24.22) of 2013-12-22 on binet, modified by Debian according to C-h C-a
Other than that, emacs is an amazing program I wish I'd used before, and which has now all but replaced libreoffice for me (with the help of RST). Now to learn to touch type...
Many thanks in advance for your time.
[EDIT]: I was wrong, the point moves as well and I hadn't noticed (see below). The variables suggested below are useful, however.

Check your value of user option scroll-margin: C-h v RET scroll-margin RET. The default value is 0. Try setting it to 2.
There are also other scrolling-related options whose values you can check. Try M-x apropos-option RET ^scroll RET. (Ignore any hits for scroll-bar.)

Related

emacs with nrepl.el for Clojure - how to hide a popup buffer?

I'm using emacs 23 (acquamacs) and have installed nrepl.el.
I've evaluated some Clojure code with
C-c C-p
(this key combo is to Evaluate the form preceding point and display the result in a popup buffer.)
Running it has produced a nice popup buffer for me to see the results.
How do I hide this popup buffer? (I don't want to kill it - just get my fullscreen back).
FYI Re this command - I've run this with
C-h k C-c C-p
and got
^C ^P runs the command nrepl-pprint-eval-last-expression, which is an interactive compiled Lisp function in `nrepl.el'.
It is bound to ^C ^P, <menu-bar> <nREPL> <Eval last expression in popup buffer>.
(nrepl-pprint-eval-last-expression)
Evaluate the expression preceding point and pprint its value in a popup buffer.
You haven't provided enough information for anyone to test (that's not a standard global binding), and you haven't even indicated whether the new window is selected; but there's a generic solution which will work regardless.
Add (winner-mode 1) to your init file, and then you can always use C-c<left> to undo the most recent window configuration change (or changes plural, if you repeat the command).
Either that or just press q. I just tried it out with the help buffer and it dismisses the window but not the buffer. However, popup buffers in the style of ac-nrepl does for its autocompletion are meant to simply be dismissed
Always, when asking Emacs questions, say what the key sequence does. C-c C-p does nothing here. TO find out what it does press C-h k C-c C-p and report back. In this case we're invoking 'describe-key and then telling it to describe what C-c C-p does.

C-y doesn't yank in emacs under tmux

Update
What's happening is that whenever I kill some text, it gets added to the kill-ring followed by an extra "". Then C-y just inserts the "". So the question is where is the extra "" coming from?
Original Question
I'm running emacs under tmux, and I can't get C-y (or even M-x yank) to insert content from the kill-ring. I do see Mark set in the minibuffer, which is normal behavior for yank; I just don't see anything getting yanked. I also see that "" gets added to the kill-ring each time I hit C-y.
I know that C-y is getting received by emacs by looking at the output of M-x view-lossage, and I know that C-y is bound to yank by looking at the keybindings with C-h b. Moreover, running M-x yank directly gives the exact same results.
When I repeat the experiment outside of tmux, it works as expected. For what it's worth, if I repeat the experiment with screen instead of tmux, C-y works as expected.
Some more details are that within tmux, I have tried running emacs with TERM=xterm-256color and TERM=screen-256color with the same result. Setting xterm-keys on or xterm-keys off in tmux doesn't seem to matter either. I've been closing every tmux session between each permutation I try, to make sure that my .tmux.conf is getting re-processed (And I know it is because other changes in my .tmux.conf do have an effect.)
In fact, I can even comment out my entire .tmux.conf, with the same result.
Also, I've tried it in both iTerm2 and Terminal.app (I'm on a mac), again with the same result.
So, I feel like I am at a dead-end here. Any ideas on how to better debug this problem?
I finally tracked it down to some code I had copied into my emacs init.el to allow copy-and-paste from my OSX clipboard. If I remove that code from my init.el, C-y works fine under tmux. (The code is here -- it worked great until I decided to try out tmux!) I'm still not sure exactly what the problem is, but it's easy to believe that it would affect the behavior of C-y.

How do I determine why emacs indented a certain amount?

In Emacs I'm editing some source code, and I hit <tab>. Emacs indents the line to n spaces. I'd like to change the amount that indents for that kind of line. How do I figure out what rule emacs applied to indent that line by n spaces?
I want to change n, but I need to figure out which of the many indentation-related variables Emacs just used.
A generic answer is difficult. Some modes will make this more apparent than others, but in the general case (as they are free to implement indentation however they wish) I don't think you'll get away from needing to read some elisp.
Starting with the binding for TAB will work, but might be slightly time-consuming depending on how many layers of indirection are involved.
If you know that the major mode in question implements its own indentation, then one (non-rigorous, but fast) approach that you could try to help track down the functions being called is to use ELP, the built in elisp profiler. elp-instrument-package will instrument for profiling all functions with names matching the prefix string argument you specify. Therefore you might do something like the following in a PHP file (noting that php-mode tells you that it is derived from c-mode)
M-x elp-instrument-package RET php- RET
M-x elp-instrument-package RET c- RET
M-x elp-instrument-package RET indent RET
Now type TAB in your source code, and run M-x elp-results to see which of those instrumented functions were called.
At this point you're on your own -- look for the likely suspects, and see what the code is doing -- but it can be a handy way to filter the search.
Once you've finished, use M-x elp-restore-all to prevent any further profiling.
If you're using a mode based on cc-mode (e.g. c-mode, c++-mode, java-mode, etc.), you can hit C-c C-s and it'll tell you what syntactic category the line is. If you want to change it, hit C-c C-o and you'll be guided through the process. Check out the cc-mode docs on customization for more details: https://www.gnu.org/s/emacs/manual/html_node/ccmode/Customizing-Indentation.html
If you happen to enjoy getting your hands really dirty, there's always the elisp debugger to tell you just what Emacs is up to.
If you hit C-h k TAB you'll find the function that Emacs is running (e.g. indent-for-tab-command) then you can do M-x debug-on-entry RET indent-for-tab-command RET. Now whenever you hit TAB you'll pop up a debugger and can watch the execution step by step.
Depending on your taste for debugging, it's either a maddening or enlightening experience. Either way, don't forget to M-x cancel-debug-on-entry when you're done.

emacs M-e doesn't work properly in tex-mode

I'm using emacs and auctex to write LaTeX documents. For some reason, M-e doesn't move to the end of the sentence in tex-mode as it did when I went through the tutorial. It moves to the end of the paragraph. (That is, it moves to just before the next double line break)
What is wrong? Do I need to turn on/off some mode to skip to the next full stop? How do I check which modes are active?
I noticed that the same happens in my Emacs. The problem is that the variable sentence-end-double-space is set to t. This means that Emacs expects a sentence to end with a double space. By setting to nil things work properly, i.e., Emacs recognizes a period followed by a single space as the end of sentences.
The first thing to check is what M-e is bound to. In tex-mode, for me, it is bound to forward-sentence. You find this out by C-h k M-e.
It sounds as though it's bound to forward-paragraph, in which case I'd check your .emacs file to see if you've got any overrides in tex-mode hooks, or other things. You can also try running without your .emacs: emacs -q, and seeing what M-e is bound to (to determine if it truly is your .emacs). You can also start without the site lisp file emacs -q --no-site-file - in case your administrators have added anything.

Is there a (repeat-last-command) in Emacs?

Frequently, I've dug into apropos and docs looking for something like the following only to give up to get back to the task at hand:
(repeat-last-command)
do the last C- or M- command I just executed (to be rebound to a fn key)
or sometimes the related:
(describe-last-function)
what keystroke did I just mistakenly issue, the effect of which I'd like to add to my bag of tricks. describe-key is close, but requires knowing what I typed.
Am I simply asking too much from my trusty sidekick?
Repeat functionality is provided by the repeat.el Emacs Lisp package, which is included with standard Emacs distributions. From repeat.el's documentation:
This package defines a command that
repeats the preceding command,
whatever that was, including its
arguments, whatever they were. This
command is connected to the key C-x z.
To repeat the previous command once,
type C-x z. To repeat it a second time
immediately after, type just z. By
typing z again and again, you can
repeat the command over and over.
To see additional information about the repeat command, type C-h F repeat RET from within Emacs.
Repeat last command
C-xz
Once you pressed it, just press only
z
after that and it will repeat (without having to press C-x again).
Yes, there is a repeat command. It's called repeat:
You can repeat commands with C-x z, and hit z to keep repeating.
A bit shocking nobody mentioned repeat-complex-command, available from the key binding C-x ESC ESC.
with regards to 'describe-last-function':
There's a variable last-command which is set to a symbol representative of the last thing you did. So this elisp snippet - (describe-function last-command) - ought to bring up the documentation for the thing that immediately happened.
So you could make a trivial working describe-last-function like so
(defun describe-last-function()
(interactive)
(describe-function last-command))
Put that elisp in .emacs or equivalent, and you'll have a M-x describe-last-function.
If you've banged on a few keys or done something that modified last-command since the thing you're interested in, the command-history function might be of interest. You can get that by M-x command-history
Also, M-x view-lossage shows you the last hundred(?) keystrokes you entered. So, you'll be able to see where the command is. It's what i used until i just right now found out about M-x command-history which i think i'll be using with C-h w now.
I'm not really sure, but maybe you are searching for this one?
The command C-xz (repeat) provides another way to repeat an
Emacs command many times. This command repeats the previous Emacs
command, whatever that was. Repeating a command uses the same arguments
that were used before; it does not read new arguments each time.
Emacs Manual, 8.11 Repeating a Command
May be this would help too...
From emacs Help verbatim:
C-x M-ESC runs the command repeat-complex-command
which is an interactive compiled Lisp function in `simple.el'.
It is bound to <again>, <redo>, C-x M-:, C-x M-ESC.
(repeat-complex-command ARG)
Edit and re-evaluate last complex command, or ARGth from last.
A complex command is one which used the minibuffer.
The command is placed in the minibuffer as a Lisp form for editing.
The result is executed, repeating the command as changed.
If the command has been changed or is not the most recent previous command
it is added to the front of the command history.
You can use the minibuffer history commands M-n and M-p
to get different commands to edit and resubmit.
Personally I found Sebastian's idea useful. Here is a working version
(global-set-key "\C-r" #'(lambda () (interactive)
(eval (car command-history))))
This is old, but Google pops post this up first when I was looking to retrieve the last command I typed at the Emacs prompt. None of these answers worked for me so I decided to put in my two cents for those who might stumble upon this later on as I did. I'm using Portacle, but I found what I was looking for in here so I'm hoping it's generic enough to work with different setups. Anyway, what worked for me is using C-&uparrow; and C-&downarrow; to cycle through the history. Using M-p and M-n worked as well, but I prefer using the arrows since I use Bash quite a bit.
dot-mode is a way to repeat the last command(s).
From its commentary:
It emulates the vi `redo' command, repeating the
immediately preceding sequence of commands. This is done by
recording input commands which change the buffer, i.e. not motion
commands.