When using typeclasses, Coq sometimes diverges. When this happens under Proof General, Emacs also hangs.
The best way I know to recover is to interrupt emacs (C-g) and restart Coq (C-c C-x). But, instead of just killing the Coq process, this puts me in a mode where Emacs is again hung, displaying "Retracting buffer..." for a quite long time (sometimes so long that I give up and just start a whole new emacs!).
Why?
Is there a better way? (And: Is there an easy first step for viewing what is diverging in the first place when this happens?)
If emacs is hung on anything other than garbage collection, you can generally interrupt it with C-g. If C-c C-x / C-c C-c don't work, you can kill the coqtop process from process manager / from the command line with pkill coqtop.
This happens because coqtop has some loops where it does not check for interrupt, or does not check often enough, and so it does not catch the interrupt from PG in a timely manner.
Additionally, as mentioned in other answers, Set Typeclasses Debug will give you a very verbose log of typeclass resolution in the *response* and *coq* buffers.
I don't know if this actually does anything, but sometimes I find that Proof General interrupts Coq if I press C-c C-c a few times.
As for your second question, you can add Set Typeclasses Debug. to your script before invoking the problematic line. Then Coq will print a trace of its instance search in the *response* buffer in Emacs. If your script is looping, make sure you hit C-c C-c right after triggering the loop, as the trace can get very long quite fast
For the last bit, I reminded myself of
Set Typeclasses Debug.
Strange: I'm not actually sure any more whether emacs is stuck at the end or whether it's a display bug: it seems that if I switch to another screen and then switch back I find the coq exited message that I expect, right away.
I use Emacs v. 22 (the console version, either remotely with PuTTY or locally with Konsole) as my primary text editor on Linux. It takes a while to load up each time I start it though, probably almost a second, although I never timed it. I tend to open and close Emacs a lot, because I'm more comfortable using the Bash command-line for file/directory manipulation and compiling.
How can I speed up the start-up time?
Others have covered using gnuserve and emacsclient, and I'd suggest compiling within emacs (being able to jump to compilation errors is a win).
But, specifically speeding up the .emacs can be done by:
Byte compiling the .emacs file, which you can do automatically by using this snippet of code
Replacing as many of the (require 'package) statements with autoloaded functionality. This will delay loading of lisp until it's actually required. Using this technique allowed me to speed up my startup from >6 seconds to <1. This takes a little bit of work because not all libraries come properly marked autoload.
Removing code/functionality you no longer use.
Try running emacs with the option --no-site-file to avoid loading unnecessary packages in the site installation site-start.el.
If you are really serious, you can roll your own emacs with your favorite functionality already loaded. This, of course, means it's more involved to make changes to what you have in your .emacs because it's a part of the binary. Follow the link for information on how to use dump-emacs.
Buy a faster computer and/or faster disk.
How to determine what your .emacs loads
Now, how do you find out what your .emacs loads? With the goal to remove the functionality, or to delay it? Check your *Messages* buffer, which contains lines like:
Loading /home/tjackson/.emacs.tjackson.el (source)...
Loading /home/tjackson/installed/emacs/lisp/loaddefs.el (source)...done
Loading /user/tjackson/.elisp/source/loaddefs.el (source)...done
Loading autorevert...done
Loading /home/tjackson/.emacs.tjackson.el (source)...done
If you'll notice, the Loading statements can nest: the first .emacs.tjackson.el ends with ... and the last line shows the .emacs.tjackson.el load is ...done. All those other files are loaded from inside my .emacs.tjackson.el file. All the other loads are atomic.
Note: If you have a large .emacs, it's possible that the *Messages* buffer will lose some of the messages because it only keeps a fixed amount of information. You can add this setting early on to your .emacs to keep all the messages around:
(setq message-log-max t)
Note: It the 'load command will suppress the messages if its fourth argument nomessage is non-nil, so remove any such invocations (or, advise 'load and force the fourth argument to be nil).
In addition to Adam Rosenfield's solution, I recommend to use Emacs in server mode. You may add (server-start) to your dotemacs, and run emacsclient instead of emacs whenever you want to open file in Emacs. That way you have to pay the loading cost of Emacs only once, after then clients pop up immediately.
Edit
You're right, v22 does not create a new frame. Create a shell script that do the trick:
#!/bin/bash
# Argument: filename to open in new Emacs frame
/usr/bin/emacsclient -e '(let ((default-directory "`pwd`/")) (select-frame (make-frame)) (find-file "'$1'"))'
Edit 2
In v24+, you can do emacsclient -c to create a new frame.
Don't close Emacs every time you want to use the shell. Use Ctrl-Z to move Emacs to the background and the fg command in Bash to move it back to the foreground.
A couple of tips:
Use autoloads
Using autoload saves you from loading libraries until you use them.
For example:
(if (locate-library "ediff-trees")
(autoload 'ediff-trees "ediff-trees" "Start an tree ediff" t))
Compile your .emacs
Gives you a slight speed increase although there are pitfalls if you
work with version control and your .emacs is newer than .emacs.elc.
One common trick is:
(defun autocompile nil
"compile itself if ~/.emacs"
(interactive)
(require 'bytecomp)
(let ((dotemacs (file-truename user-init-file)))
(if (string= (buffer-file-name) (file-chase-links dotemacs))
(byte-compile-file dotemacs))))
(add-hook 'after-save-hook 'autocompile)
Learn to love emacs server.
Running emacs as a server means never having to close it down. However
I note your still using emacs22. emacs23 supports multi-tty which makes
it a lot easier to run emacs in one screen session and then bring up
new windows in another terminal. I use emacs to edit mail for my mail
client (mutt) and emacsclient is fantastic for these sort of quick edits.
One of
M-x shell
M-x eshell
M-x term
M-x ansi-term
should meet your command-line needs from within Emacs.
You can also use M-! (aka M-x shell-command) to execute a one-liner without dropping to the shell.
Check your .emacs file to see if you're loading unnecessary packages. Loading packages can take a significant amount of time. For example, you might only want to load the php-mode package if you're editing a PHP file. You can do that by installing a hook procedure, although I'm not certain of the details.
Also make sure that any packages you're loading are compiled (.elc files). You can compile an elisp file by running
emacs -batch -f batch-byte-compile thefile.el
Compiled packages load much faster than uncompiled packages.
"I tend to open and close emacs a lot, because I'm more comfortable using the bash command line for file/directory manipulation and compiling."
You're describing the way an editor like vim is used like. Shoot in&out. Emacs is usually kept open, and mostly all is done from "within it". hiena already answered what would be the correct approach here.
The fastest way is to profile your .emacs. I cut down my load time from >3s to 1s in 5 minutes after I found that 4 particular lines in my .emacs were taking up more than 80% of the load time.
One thing that helped me reduce the load time of my .emacs, in addition to autoload (as others have suggested), is eval-after-load. In the following example, delaying the call to sql-set-product saves you from having to load sql in your .emacs, making the exisiting sql autoloads more effective.
(eval-after-load "sql"
'(progn
(sql-set-product 'mysql)
(setq sql-mysql-options '("-C" "-t" "-f" "-n"))
(setq sql-sqlite-program "sqlite3")
))
Of course, for some packages there will be a hook available that you can do the same thing, but sometimes there isn't, or else this way just proves easier to think about.
Emacs is designed to run "all the time" (or at least for long periods of time), thus starting and stopping Emacs several times during a day is not recommended.
I would suggest using screen. Screen is a terminal multiplexer, giving you an unlimited virtual terminals in one terminal.
After installing simply write "screen emacs" in your terminal. Emacs will start as usual, but pressing "c-a c" (that is press ctrl-a and then c) will open a new virtual terminal. You can get back to emacs by pressing "c-a c-a" (that's two times ctrl-a).
You can even detach from the running screen session, the key sequence is "c-a d".
Re-attach to the session by issuing "screen -R" and you will be back where you left. This enables you to start an emacs session at work, detach, go home, and re-attach from home.
I've been running Emacs like this for months in a row.
Here's the official web site: http://www.gnu.org/software/screen/ but try googling for screen tutorials and howtos
You can use benchmark-init to profile your Emacs startup. It will keep track of what modules are being loaded and how much time is spent on each. The results can be presented either in a tabulated form or as a tree. The tree makes it easier to track who loads what, which can be helpful when you load a package with a lot of dependencies, and the tabulated form helps you quickly find where most of the time is being spent.
Once you have these results try to figure out if all of the modules have to be loaded all the time or if you can perhaps load some of them on-demand. For instance, in my configuration I only load Emacs extensions that are specific to certain modes when that mode is actually activated since most of the time I only use a small subset of them in a session. eval-after-load and mode hooks will be your friends here.
By applying this method my Emacs starts in 3-4 seconds and I have close to 200 extensions installed. Most of the time is spent loading Helm, which I always load since it replaces find-file and other core functions that are always needed, and CEDET, since I use the latest version and it has to be loaded before Emacs tries to load the older built-in version.
Try using the https://github.com/jwiegley/use-package macro to define your package loads and customizations. It handles deferred loading of packages for you, making it relatively easy to get good startup times even in the presence of large numbers of configured packages. I have almost 100 packages referenced in my .emacs, but my startup time is under 2 seconds on Linux, and 2.2s on the Mac.
One thing that others haven't mentioned is to include the elisp libraries you use as part of the dumped Emacs to move the library loading time from Emacs startup to Emacs build. It is not for the faint-hearted, but if you load several libraries in .emacs it could win you a few seconds of startup time.
I had around 120sec start time. I was able to find the fix installing this:
https://github.com/dholm/benchmark-init-el
put on top of your init.el
(let ((benchmark-init.el "~/.emacs.d/el-get/benchmark-init/benchmark-init.el"))
(when (file-exists-p benchmark-init.el)
(load benchmark-init.el)))
then once your emacs started, run:
M-x benchmark-init/show-durations-tree
On my side the problem was 127 secs in tramp-loaddefs
I fixed it by adding
127.0.0.1 host.does.not.exist
to /etc/hosts and that made my startup fast
see more here: https://github.com/emacs-helm/helm/issues/1045
another thing that maybe helpful to you: https://www.emacswiki.org/emacs/ProfileDotEmacs
This doesn't answer the question, but is kind of relevant
I don't know how to make it start faster, but there are a few things I could suggest:
for most things you do on the command line, you can do them in emacs:
compile: M-x compile, then type the command you use
my experience is only with C++, but with g++ you can press C-x ` to jump to lines that the compiler complains about
run shell commands: M-!, dumps output into a buffer
interactive shell: M-x shell
alternatively, you could run emacs like this:
emacs file.ext &
which opens emacs in the background so you can still use the shell ( this works best with putty and X forwarding with something like Xming)
I was trying to solve the same problem, when I came across this question here. I just wanted to add that the problem for me was not because of the load time of emacs lisp packages, but the fact that the host did not have a fully resolved hostname
To check your package load time do
M-x emacs-init-time
For me it was 0.3 seconds, and yet the load time was extremely high.
After changing my hostname correctly, it fixed the problem.
To configure your fully resolved hostname edit /etc/hostname, and /etc/hostsfile with:
127.0.0.1 localhost localhost.localdomain
192.168.0.2 hostname hostname.domain
I would have to check my customization, but there is a package called gnuserve or emacsclient. It migrates a lot so you will have to google for it.
It runs one emacs session in the background. Any further sessions of emacs are essentially just new frames of that session. One advatage is quick startup times for your later sessions.
I have a small GTK python application that imports a package (Twisted) that may not be loaded twice.
If I run my application in emacs with python-mode.el and press C-c C-c, the application gets executed in a python shell window.
If I now close the application, the python shell stays up and running. If I now press C-c C-c again, emacs "reuses" the old python process and thus I run into problems because I'm installing a Twisted reactor twice.
Is it possible to have python-mode.el open a new shell window each time I execute a buffer?
python-mode.el comes with a command py-execute-buffer-dedicated,
opening a new and reserved process for it
In python.el, a new inferior process is launched in a new buffer if the python-buffer variable is set to nil. Therefore, it's possible to advise the python-send-buffer function to reset that variable to nil after every invocation, thereby forcing a new Python process to be executed for every subsequent python-send-buffer command. Something like the following should work:
(defadvice
python-send-buffer
(after python-send-buffer-new-proc activate)
(setq python-buffer nil))
(ad-activate python-send-buffer)
I know that your post was asking for help with python-mode.el, but I thought it might be helpful to mention this anyway, as I'd surprised if python-mode.el doesn't use a similar mechanism. If I have time, I'll try to look into it.
Edit: the python-mode.el package uses the command py-shell to initiate a new inferior Python process. I found a mailing list posting in which a user provides an ad hoc function that appears to do what you need.
By the way, it might be worth considering that trying to alter the default behavior of python-mode isn't the best approach to this problem. I don't know what your code does, and I'm not particularly familiar with Twisted, but it seems to me that experiencing major errors when evaluating your code a second time within the same session could be a sign of a more fundamental design problem. I fail to see how it could be a matter of multiple imports of the same module being the issue, as Python modules are only loaded once, with successive import statements having no effect (for that, an explicit reload or execfile() is required). If I'm completely off-base here, I apologize, but I felt this possibility might merit mention.
I am using emacs and the auto-newline feature is not working as expected. I have a pretty large number of customizations done to my emacs. So it would be no wonder if one of the other customizations is not what auto-line is expecting. I would like to know if there is a way to know the list of commands (list of emacs commands) executed by emacs at a particular point, for e.g. when ctrl-s ctrl-c or in my case when auto-line feature is called.
edit : I think you have misunderstood the question. I would like to know what command emacs calls 'internally'.
I believe view-lossage is what you're looking for -- M-x view-lossage, or C-h l.
If you want to know what a keystroke is bound to, consider using describe-key, which is usually bound to C-h k.
Basically at this point, you need to bite the bullet and learn some Emacs-lisp. The debugger is what you are looking for to dig further into your problem (I use edebug). It's not just about seeing what functions get called, you also need to see the values of the relevant variables when those functions are called.
If you feel you're not up to it, then you can bi-sect your init file until you find the culprit, but at that point you still need some Emacs-lisp to investigate further.
To add to what #event_jr said --
What you seem to be asking is the history of the functions called by the command you last invoked. (You speak of Emacs "internal commands", but it seems you just mean functions.)
To get that history for any given command you invoke (e.g., by a key), use M-x debug-on-entry and then enter the command name. The next time you use that command, you can walk through its execution in the Emacs debugger (hit d to step, c to continue past a step).
I'd like to be able to open two windows in Emacs, select a region of text in each window, and get a comparison of the difference between the two selections.
This would be very handy for a large-scale maintenance project, where I'm working on a version tree with multiple branches, lots of copy/paste, and code that is being moved around sporadically.
I've found a paid-for tool that does provide this function (Ultracompare), but it's windows-specific, and I need a solution that runs on Solaris/Linux.
I think M-x ediff-regions-wordwise does what you want.
Run ediff-regions-wordwise and Emacs will prompt for each buffer, then prompt you to select (or confirm) a region in the buffer.
And, bonus, Emacs runs on Windows too!
I'd be inclined to use narrow-to-region (C-x n n) in both buffers followed by M-x compare-windows if only because it has worked for me for at least 100 years. :-)