Emacs, clojure, cider-jack-in - emacs

Originally when I started to use emacs with clojure, and cider-jack-in, when I opened Parenthesis, eamcs automatically closed it.
also, if I was on the first character of this code
(dotimes [n 3]
(println "hi" n))
and press CTRL-k, emacs cut both lines.
Somehow I lost these features. I tried to reopen emacs and run emacs-jack-in again, but it is not working like that anymore. How could I turn it on again?
thanks

Related

In Slime REPL (GNU EMACS), what is the shortcut to clear the current input

In Slime, I would like to clear the input I have currently typed into the REPL topline. What is the shortcut?
For example, if I type the below, it is missing one parenthesis and will not execute. How do I simply clear the whole text from my input line? I.e. instead of having to manually press delete on each character
(let* ((x 5) (y (+ x x))
(print y))
I could not find anything here:
https://common-lisp.net/project/slime/doc/html/REPL-commands.html
These solutions seem to be different (but please correct me if I'm wrong) and relate to the whole screen, while I'm interested in clearing what I have typed but not yet evaluated:
emacs cider clear REPL buffer
In emacs, how do I bind C-l to clear screen in slime?
It's C-c C-u, which is slime-repl-kill-input. A good trick is to use C-h b which will cause Emacs to show you the current bindings in a help buffer: you can then search through them looking for likely candidates. C-h m is also useful to show help on the current mode, which should show you the bindings as well (but may not: I'm not sure if it always does). The advantage of these things is that they show you what actually exists rather than what the manual thinks exists which may not be the same thing (even when there is a manual...).

Launch make and go to the error position by shortcuts within Emacs

I use Emacs to code. At the moment, to compile an OCaml project, I need to type make in a terminal. If there is an error, I have to go back to Emacs to find the erroneous file and location by following the error indication.
Now, I would like to launch make inside Emacs by a keyboard shortcut, which opens a buffer to show the compilation, then
1) if there is no error, then close the buffer automatically
2) if there is an error, another shortcut will lead me to the erroneous file and line within Emacs.
Does anyone know how to write .emacs to enable this mechanism?
PS: This is my current .emacs.
I have posted a question to compile one .tex file within Emacs by a shortcut (Ctrl + c + m + m), this works well. But in case of error, I don't ask it to lead me to the error position.
M-x compile RET
See the Emacs manual, node Compilation.
And see node Compilation Mode for how to visit error occurrences.
Some years back, I had the same question, here's the answer I got on the #emacs irc channel.
;; from enberg on #emacs
(setq compilation-finish-function
(lambda (buf str)
(if (null (string-match ".*exited abnormally.*" str))
;;no errors, make the compilation window go away in a few seconds
(progn
(run-at-time
"2 sec" nil 'delete-windows-on
(get-buffer-create "*compilation*"))
(message "No Compilation Errors!")))))
;; save the file when I press compile
(setq mode-compile-always-save-buffer-p t)

Killing Racket Infinite Loops in Geiser

When I accidentally make an infinite loop by evaluating a form in emacs with geiser + racket, after a minute or so of waiting, eventually emacs will start to respond again. Unfortunately, every eval after that takes at least a minute. Usually, after the second or third eval, emacs will stop responding at all, and the fastest thing to do at that point it to restart the Ubuntu machine.
Is there some setting to prevent this in geiser, or a way to tell emacs to kill geiser?
Here's what I do when something hangs up.
Over the years, I don't recall Emacs being stuck in an unrecoverable state.
Use C-g. Repeatedly if needed. It calls keyboard-quit.
This should break any stuck loop and give you the ability to enter commands.
Now if geiser or any other process is misbehaving, just kill the buffers
that correspond to this process.
C-x C-b will give you the list of all buffers.
If you don't recognize the one that belongs to geiser, just restart Emacs
and open only geiser and see the buffer list again.
Now mark the misbehaving buffers with d.
Execute the deletion with x. That's it. You can
now restart geiser or whatever else. This approach is completely generic.
By the way, restarting the Ubuntu machine is too drastic.
When nothing works to stop the application with a window, but X still works,
use xkill utility. I've bound it to Ctrl-Alt-F12 for instance.
Then you just click on a window you don't like and it's gone.
If xkill doesn't work, switch to a virtual terminal with
Ctrl-Alt-F1 and use htop to kill the application.
According to the REPL documentation, you should be able to use C-c C-q to kill the REPL. From the link to the REPL documentation, go to the First Aids section; it's near the bottom of it.
Geiser hangs on loops here also. In emacs 24.3.1 running on Debian 7 updated two days ago; M-x run-geiser; Then one gets a window with a REPL prompt. All is good, but then say > (define f (* f (- n 1))), then > (f 3) and the process in the buffer is locked up. C-c C-c and C-c C-q do nothing. Killing the buffer, answering yes to the query of killing subprocesses, and then restarting does get one to a REPL prompt with all definitions gone.

Evaluating Elisp in emacs

I am an hour new into programming in Emacs lisp. I have a little experience with scheme so I understand the big picture of lisps in general. However, I have only used the "pure functional" subset of scheme and do not know how to do practical tasks.
Write now, I know that C-x C-e will evaluate the code enclosed by the parentheses' by the current cursor position.
I wish to loop from i = 1 to 10 and print the values of i out. How is this done? I tried the following:
(defvar i 1)
(while (< i 11)
(print "i: " i)
(setq i (+ i 1)))
Emacs tells me: invalid function 0.
How do I do this correctly?
Why is emacs telling me invalid function 0
Feel free to give me tips about how to use the scratch buffer (all I know is C-x C-e evaluates) in emacs. Thanks for all the help!
EDIT1: Could someone tell me how to print out sequential values of i using a while loop?
EDIT2: When I evaluate the code, it opens up another tiny buffer showing each value of i one at a time. However, it is not a large buffer and only shows values of i from 13 to 19. When I try to get into that buffer, it closes immediately. How do I "scroll" through that tiny buffer? Note that I use emacs 24.3 through the terminal
EDIT3: I figured out that the tiny buffer is the Messages buffer. Is there a better way to view the output of my elisp code? The Messages buffer is full of other junk from evaluating things in emacs.
First and foremost, enable "Enter debugger on error" from the Options menu now and add (setq debug-on-error t) or (custom-set-variables '(debug-on-error t)) to your ~/.emacs.el.
Then you will get a *Backtrace* buffer on C-x C-e:
Debugger entered--Lisp error: (invalid-function 1)
1(10)
print("i: " 1)
(while (< i 11) (print "i: " i) (setq i (+ i 1)))
eval((while (< i 11) (print "i: " i) (setq i (+ i 1))) nil)
eval-last-sexp-1(nil)
eval-last-sexp(nil)
call-interactively(eval-last-sexp nil nil)
command-execute(eval-last-sexp)
which shows that the error comes from print.
C-h f print RET will tell you why, but the upshot is that you want to use insert instead of print here.
Just as an added note, since you mentioned knowing some scheme -- if you like the interactive REPL that you can use in typical scheme environment, you might like ielm -- I think it probably stands for Interactive Emacs Lisp mode. Not sure. Anyway, M-x ielm RET will open up an emacs lisp REPL. Sometimes it is actually useful -- for example, when you want to inspect the content of a variable with a lot of data in it, ielm will print the whole thing out. Ielm is built in to my Emacs. Not sure when it was added to the standard distribution, but the earliest copyright in the source says 1994, so it is probably in your Emacs.
You can evaluate Emacs-Lisp sexps in *scratch* or in any other buffer in the same mode or (my preference) in mode emacs-lisp-mode.
In *scratch* you need only hit C-j (newline) after a sexp to evaluate it. In an emacs-lisp-mode buffer you can, as you said, use C-x C-e after a sexp. Or you can use M-x evaluate-region after selecting one or more sexps. As always, C-h m in any mode tells you about it, and usually lists important key bindings.
You can also check a global variable value using C-h v SOME-VAR. And you can evaluate any sexp on the fly from the minibuffer, using M-:. For example: M-: (setq foo (+ 42 (length bar)))
Wrt the debugger:
As #sds mentioned, debug-on-error puts you in the debugger when an error is raised. You can also set debug-on-quit and then enter the debugger using C-g to quit (e.g., during a loop).
If you know the function you want to debug, you can use M-x debug-on-entry.
Step through the debugger using d, or skip to the end of a step using c. Use q to quit the debugger.
You can also insert calls to function debug in source code, as debugger entry points: (debug).
The backtrace in the debugger is always more informative if you load the relevant source file e.g., foo.el, instead of the byte-compiled file, e.g., foo.elc. So before you use M-x debug-on-entry use C-h f to find out which file the function is defined in, and then load that file using M-x load-file /path/to/the/file.el.
There is also another debugger, besides debug -- look for edebug in the Elisp manual. Some people prefer edebug; I prefer debug.

Emacs Clojure mode without paredit

I'm using the Clojure mode package from ELPA. Otherwise everything is fine, but I just can't stand paredit mode. I can't seem to turn it off easily, now I just disable it for every buffer I open. I tried setting this variable to nil:
(setq clojure-enable-paredit nil)
But paredit still appears. Any ideas?
Not an answer to your actual question, but give paredit mode a chance. I, too, was really annoyed with it automatically closing my parens, and refusing to delete just a single paren for me.
But doing this enables it to be certain at all times that the buffer is a well-balanced sexp, so it can perform many useful sexp-oriented tasks for you instead of just text-oriented tasks. For example, I use the following all the time:
M-( to wrap a sexp with a new one, eg turn (map f some-list) into (doto (map f some-list) println)
C-) to "slurp" another sexp into the current one, eg turn (let [x 10]) (println x) into (let [x 10] (println x))
M-<UP> and/or M-r to pull the sexp at point a level "higher" in the source tree, destroying the thing that was wrapping it, eg to turn (first (map f some-list)) into (map f some-list) or (first some-list)
There are zillions of useful features like this, that let you start editing code instead of text. And while there are plenty of excellent Lisp hackers who don't like paredit mode, I advise you not to decide against it before you realize the awesome stuff it can do for you.
Found one trick that works. Before the elpa packages are loaded in init.el, add this hook to clojure mode:
(add-hook 'clojure-mode-hook (lambda () (paredit-mode nil)))
For what it's worth, I use clojure-mode through ELPA too, and it doesn't imply paredit. Maybe just uninstall it? I find clojure-mode, slime and slime-repl are the only packages I need to install on a clean EMACS to get clojure/swank/slime working.
I only tested this:
http://www.learningclojure.com/2010/08/clojure-emacs-swank-slime-maven-maven.html
a few weeks ago, and it still works fine.