before defadvice not executing before the function? - emacs

[I apologize for the poor title, but couldn't come up with a better one.]
bin chen asked on Google+:
How to input relative path of (buffer-file-name) in minibuffer after M-! in #emacs?
I thought if the buffer-file-name is saved in a register, it should be accessible by invoking insert-register (C-x r i) while at the shell-command prompt.
(defun save-buffer-file-name-in-register ()
(set-register ?F (buffer-file-name))
(set-register ?D (file-name-directory buffer-file-name)))
(defadvice shell-command (before save-buffer-file-name)
"Save buffer-file-name to register F before running shell-command"
(save-buffer-file-name-in-register))
(ad-activate 'shell-command)
When I invoke shell-command (M-!) followed by insert-register (C-x r i), I get the error message: Register does not contain any text.
But when I run list-registers I do see that the registers F and D are set with the appropriate values. If I run the shell-command again, I can access the values from the registers previously saved.
Is it possible that the registers are being set too late for the first time? How can I fix the code to do what I want?
Edit: Changed around to before (Thanks to #phils)

n.b. You have defined around advice, not before advice.
Around advice acts as a wrapper, and must include the token ad-do-it to execute the code of the function it is wrapping.
You have effectively replaced the body of the shell-command function with a call to save-buffer-file-name-in-register
As to your main question, I'd need to check the documentation, but I suspect that because the arguments to the advised function are available to advice, the original function's interactive declaration probably executes before the advice does, which would explain why your register values are not visible at the interactive shell-command prompt.
(If the around in the above code is indeed what you were using, the fact that you were still being prompted for a shell command would seem to verify this sequence.)

When the interactive form runs, your advice hasn't executed yet. See: this question
You need to specify an interactive form in your advice that redefines the original if you want to stick with this approach. However, this approach is a little fancy-pants for the sake of fancy-pants-ness.
Just define your own interactive function which does what you want without registers.
(defun insert-cur-dir ()
(interactive)
(let ((dir-name (file-name-directory (buffer-file-name (window-buffer (minibuffer-selected-window))))))
(insert (or dir-name ""))))
(define-key minibuffer-local-map (kbd "C-c i") 'insert-cur-dir)
An alternative, but way awesomer approach is to use yasnippet.

Related

Emacs command history including commands called by keys and with arguments passed to them

Is there a way to show full command history with arguments?
repeat-complex-command which is bound to:
<again>, <redo>, C-x M-:, C-x M-ESC
does not show commands that are invoked from key bindings, and kmacro-edit-macro (which is bound to C-x C-k RET) does not show arguments passed to commands.
Motivation. It would make it faster to turn a keyboard macro into an elisp function. For now, I invoke kmacro-edit-macro to see names of commands to use and then work out what arguments to pass by reading documentation of commands one by one. (Example workflow: https://stackoverflow.com/a/24784563/1446335)
Note. It is possible to programmatically press key sequence from within an elisp function, but its usefulness is small.
Yes, to get what you want, use pre-command-hook to invoke a function that adds the given command to extended-command-history. For example, this is what the Icicles code does to add commands executed by menu to this history:
;; This is done when you turn on Icicle mode.
(if icicle-menu-items-to-history-flag
(add-hook 'pre-command-hook 'icicle-add-menu-item-to-cmd-history)
(remove-hook 'pre-command-hook 'icicle-add-menu-item-to-cmd-history))
(defun icicle-add-menu-item-to-cmd-history ()
"Add `this-command' to command history, if it is a menu item.
Menu items that are not associated with a command symbol are ignored.
Used on `pre-command-hook'."
(condition-case nil ; Just in case, since this is on `pre-command-hook'.
(when (and (> (length (this-command-keys-vector)) 0)
(equal '(menu-bar) (elt (this-command-keys-vector) 0))
;; Exclude uninterned symbols such as `menu-function-356'.
(symbolp this-command) (or (< emacs-major-version 21) (intern-soft this-command)))
(pushnew (symbol-name this-command) extended-command-history))
(error nil)))
It would be great to have a way to turn a keyboard-macro into a chunk of Elisp code, but for this chunk of Elisp code to be useful, it should be somewhat idiomatic, yet in many cases, the idiomatic Elisp code to do something is quite different from the keyboard-macro way to do it (e.g. idiomatic code should not use the mark and the kill ring just to extract and move text around).
So the transcription is not straightforward. I think the way to write such a thing is to "start small" and accept the fact that it will not be 100% reliable.

Strange Emacs behavior (produces garbage on the screen)

I'm trying to learn Emacs and eLisp by writing some simple macros. Here is one of them:
(global-set-key (kbd "C-c d") 'local-delete-line)
(defun local-delete-line ()
"deletes 1 line"
(interactive)
(beginning-of-line)
(set-mark-command)
(next-line)
(delete-region))
Unfortunately, after triggering C-c d (or any other hotkey that I set up by global-set-key), Emacs responds with this:
Any ideas what can cause this?
To troubleshoot, I've removed my whole .emacs file, created an empty one, and I've put only the definition of local-delete-line function, together with global-set-key command. Emacs still produces garbage when invoking the function.
Start by reading the doc of set-mark-command (C-h f set-mark-command). See what it says about not setting the mark in code you write. See how many arguments it requires.
Read the doc of delete-region: it requires two arguments.
Do M-: (setq debug-on-error t), and then try your recipe. The backtrace buffer will tell you what you have done wrong.
State what it is that you are trying to do. So far, it seems like you just want to delete or kill a line. If so, what's wrong with C-k?

Emacs/AUCTeX prefix arguments

In LaTeX mode C-c C-c is bound to:
(TeX-command-master &optional OVERRIDE-CONFIRM)
Normally this interactive function runs a command, perhaps a LaTeX compilation, asking for confirmation.
In tex-buf.el it reads:
If a prefix argument OVERRIDE-CONFIRM is given, confirmation will
depend on it being positive instead of the entry in `TeX-command-list'.
This is a bit cryptic for me and reading C-h v TeX-command-list didn't help.
How can I pass the prefix argument to "TeX-command-master" so that I avoid all the confirmation requests?
Take a look at Emacs' documentation to find out about prefix arguments. In general, you can pass a command a prefix argument with C-u followed by a number. For one-digit numbers, you can also just type Meta followed by the digit. Thus to pass a positive prefix argument to TeX-command-master you could type:
M-1 C-c C-c
However, this will actually add another minibuffer confirmation, namely about the shell command to be used to compile the LaTeX source. Without the prefix argument, a command-dependent default is used for that.
If you want to avoid the question about the command to use, you can bind the undocumented variable TeX-command-force to "LaTeX" via:
(setq TeX-command-force "LaTeX")
However, this will have the downside that you're basically binding C-c C-c to the "latex" command, you cannot use any of the other commands such as "bibtex" or "view".
Other than that, LaTeX-mode does not allow for any customization of C-c C-c. Your best options are to either advise the function TeX-command-query or to bind C-c C-c to a wrapper function to set TeX-command-force dynamically. The latter would probably be the preferred option if you also want to auto-save the buffer.
It seems that the mystery of the OVERRIDE-CONFIRM continues. In the meantime a fellow suggests that, if we are unable to manage TeX-command-master, we can simply rewrite it.
In my version, based on his, if the buffer is not modified, the external viewer is launched; if the buffer is modified the compiler is run.
Everything with no confirmation for saving or running the given command.
(defun my-run-latex ()
(interactive)
(if (buffer-modified-p)
(progn
(setq TeX-save-query nil)
(TeX-save-document (TeX-master-file))
(TeX-command "LaTeX" 'TeX-master-file -1))
(TeX-view)))
Of course one can bind my-run-latex to whatever keybinding.
On the user's point of view this is a solution to my own question.
Do I click the close tag? Well, on the curious guy point of view I am still interested in understanding the mysterious TeX-command-master technicalities.
If someone should happen to know...
P.S.
Yes, TeX-save-query overrides the save-file request, also with TeX-command-master, that is C-c C-c. But you will still be asked to confirm the command action.
Build & view
Again, this solution, instead of modifying the behaviour of the TeX-command-master, rewrites it. The rewritten version of the command, named build-view, follows a rather straightforward logic.
If the LaTeX file buffer is not-modified, it runs the default viewer;
If the buffer is dirty, it runs the default LaTeX compiler and, after the build, opens the output in the default viewer.
Here's the code:
(defun build-view ()
(interactive)
(if (buffer-modified-p)
(progn
(let ((TeX-save-query nil))
(TeX-save-document (TeX-master-file)))
(setq build-proc (TeX-command "LaTeX" 'TeX-master-file -1))
(set-process-sentinel build-proc 'build-sentinel))
(TeX-view)))
(defun build-sentinel (process event)
(if (string= event "finished\n")
(TeX-view)
(message "Errors! Check with C-`")))
You can now type M-x build-view and start the told build-view process or associate it with a new keybinding such as “F2”:
(add-hook 'LaTeX-mode-hook '(lambda () (local-set-key (kbd "<f2>") 'build-view)))
Note: As suggested by Tyler, TeX-save-query variable is changed locally, therefore the old C-c C-c/ TeX-command-master is unaffected and will keep asking confirmations.
Do edit this code to make it better or easier to read!
I puzzled over the OVERRIDE-CONFIRM bit for a while, and couldn't figure out how it was supposed to work. If you want to automatically run Latex on your file, without being bothered about saving it first, or confirming that you want latex (rather than view, bibtex etc), you could use a function like this:
(defun my-run-latex ()
(interactive)
(TeX-save-document (TeX-master-file))
(TeX-command "LaTeX" 'TeX-master-file -1))
Bind this to something handy, and you'll still have C-c C-c for when you want to use the default processing commands. You may want to modify the TeX-command line if "Latex" isn't the processor you want to call.
If you are just looking to compile the latex source without a confirmation dialog, just add the following to your .emacs:
(setq TeX-command-force "")
You can then compile the source with C-c C-c and it won't ask to confirm. The only problem with this solution is that you can no longer change the command, but with most documents you won't want to. I might suggest that at the same time you can add this to your .emacs for even more flexibility, giving you a C-c C-c equivalent to the former behavior:
(define-key LaTeX-mode-map "\C-c\C-a"
;;; 'a' for ask, change to anything you want
(lambda (arg) (interactive "P")
(let ((TeX-command-force nil))
(TeX-command-master arg))))
You can then just work away at your document, do a C-x C-s, C-c C-c and then C-c C-v to see it. Like others have suggested you can also do the same for the save command and have it compile automatically on save, but some of my documents are in CVS and so I avoid putting hooks on that.
Credit to Ivan for some help on this one - don't know if he is on StackOverflow
I think the gist of this question is "how do I quickly compile my TeX document from AUCTeX without all the key presses and confirmations?"
My answer to that is to use the latexmk command rather than trying to coerce AUCTeX to do it.
latexmk -pdf -pvc myfile.tex
latexmk will monitor the file in question and rebuilt it as soon as you save it. If you use a good pdf viewer, it will notice the change in PDF and re-display it immediately. On OS X, skim works well for this.

How do I answer y automatically (kill-matching-buffers asks if I should kill a modified buffer)?

In Emacs - how do I kill buffers matching regexp?
Edit:
How do I answer y automatically (kill-matching-buffers asks if I should kill a modified buffer)?
Something like this?
(defun bk-kill-buffers (bfrRgxp)
(interactive)
(kill-matching-buffers bfrRgxp)
[return])
How do I answer y automatically (kill-matching-buffers asks if I should kill a modified buffer)?
kill-matching-buffers calls kill-buffer-ask which calls yes-or-no-p. You could temporarily redefine the latter, but for safety reasons I am inclined not to do that -- killing a given buffer could trigger other functionality which needs to ask a yes-or-no question.
Redefining kill-buffer-ask seems a safer bet (or simply copying and modifying the kill-matching-buffers function itself).
(require 'cl)
(defun bk-kill-buffers (regexp)
"Kill buffers matching REGEXP without asking for confirmation."
(interactive "sKill buffers matching this regular expression: ")
(flet ((kill-buffer-ask (buffer) (kill-buffer buffer)))
(kill-matching-buffers regexp)))
For Emacs version >=24, the kmb.el library from ELPA repository
does exactly that with the command kmb-kill-matching-buffers-no-ask.
It also provides the command kmb-delete-process-and-kill-buffer-no-ask,
which kills the current buffer (without confirmation).
I bind the latter command as follows:
(global-set-key (kbd "H-M-<delete>") 'kmb-delete-process-and-kill-buffer-no-ask)
so that i don't call it accidentaly, just when i need it.
You can use kill-matching-buffers. Below code effectively behaves as if kill-buffer (which does not ask before killing) was called instead of kill-buffer-ask:
(defun kill-matching-buffers-just-do-it ()
"Kill buffers whose names match REGEXP, without asking."
(interactive)
(cl-letf (((symbol-function 'kill-buffer-ask) #'kill-buffer))
(call-interactively #'kill-matching-buffers)))
M-x kill-matching-buffers
This will prompt for a regex, check the documentation for details.

How can I easily reload Emacs lisp code as I am editing it?

As an Emacs beginner, I am working on writing a minor mode. My current (naive) method of programming elisp consists of making a change, closing out Emacs, restarting Emacs, and observing the change. How can I streamline this process? Is there a command to refresh everything?
You might try using M-C-x (eval-defun), which will re-evaluate the top-level form around point. Unlike M-x eval-buffer or C-x C-e (exal-last-sexp), this will reset variables declared with defvar and defcustom to their initial values, which might be what's tripping you up.
Also try out C-u C-M-x which evaluates the definition at point and sets a breakpoint there, so you get dropped into the debugger when you hit that function.
M-x ielm is also very useful as a more feature-rich Lisp REPL when developing Emacs code.
M-x eval-buffer should do it.
What Sean said. In addition, I have (eval-defun) bound to a key, along with a test. The development loop then becomes: 1) edit function, 2) press eval-and-test key, 3) observe results, 4) repeat. This is extremely fast.
During development I write a test, bind it to jmc-test, then use the above key to run it on my just-edited function. I edit more, then press key again, testing it again. When the function works, I zap jmc-test, edit another function, and write another jmc-test function. They're nearly always one line of code, so easy to just bang out.
(defun jmc-eval-and-test ()
(interactive)
(eval-defun nil)
(jmc-test))
(define-key emacs-lisp-mode-map (kbd "<kp-enter>") 'jmc-eval-and-test)
(when t
(defun myfunc (beer yum)
(+ beer yum))
(defun jmc-test () (message "out: %s" (myfunc 1 2))))
When editing "myfunc", if I hit keypad enter, it prints "out: 3".
It all depends on what you're writing and how you've written it. Toggling the mode should get you the new behavior. If you're using [define-minor-mode][1], you can add code in the body of the macro that keys off the mode variable:
(define-minor-mode my-minor-mode
"doc string"
nil
""
nil
(if my-minor-mode
(progn
;; do something when minor mode is on
)
;; do something when minor mode is off
)
But, another way to check it quickly would be to spawn a new Emacs from your existing one:
M-x shell-command emacs&
I just define a function called ldf (short for load-file) in my .emacs file,
like this:
(defun ldf (arg) (interactive "P") (load-file (buffer-file-name)))
As you can see, this little function looks up the filename of the current buffer and then loads the file. Whenever I need to reload the current buffer elisp file, just type "M-x ldf"