How to find the location, where an an Emacs Lisp function is bound to a key? - emacs

I'm trying to figure out where M-m is bound to back-to-indentation function. When I issue C-h k M-m (describe-key), I get the following output
M-m runs the command back-to-indentation, which is an interactive
compiled Lisp function in `simple.el'.
It is bound to M-m.
(back-to-indentation)
Move point to the first non-whitespace character on this line.
When I look at simple.el, I'm seeing only the definition of function back-to-indentation. I searched throughout the file and I didn't see any keybinding done for that function using define-key. I'm assuming that it happens elsewhere.
How can I identify the location where the function is bound to M-m key?
Emacs version: GNU Emacs 24.2.1 (x86_64-apple-darwin12.2.0, NS apple-appkit-1187.34)

I don't know if that's possible in general, but my guess would be that Emacs doesn't remember where the code was that defined a given key.
C-hb will show the current bindings, from which you can establish which keymap you're interested in, and work from there. For most major or minor mode maps, it won't be too difficult to find the code.
Your specific example is a global binding which Emacs configures in bindings.el.

Adding this at the beginning of my .emacs did the trick for me:
(let ((old-func (symbol-function 'define-key))
(bindings-buffer (get-buffer-create "*Bindings*")))
(defun define-key (keymap key def)
(with-current-buffer bindings-buffer
(insert (format "%s -> %s\n" key def))
(mapbacktrace (lambda (evald func args flags)
(insert (format "* %s\n" (cons func args))))))
(funcall old-func keymap key def)))
The idea is that I redefine the define-key function (which is used to bind key within keymap to def) to first log its arguments to a buffer *Bindings*, together with the stacktrace of where it's being called from. After that it calls the old version of the function.
This creates a closure to store the old value of define-key, so it depends of lexical-bindings being t. In retrospect, I think it would have been possible to use function advising instead; but using a closure felt simpler.
Since I had this at the beginning of my .emacs, this recorded all calls to define-key during initialization. So I just had to switch to that buffer once initialization finished, find the call where the particular key was bound, and then inspect the backtrace to find the site from which that happened.

Related

How to extend Neotree to open a file using hexl?

I'm trying to extend Neotree to open a file using hexl-mode with the shortcut C-c C-x. How would one do this?
I've tried to evaluate a key definition after the Neotree load where it uses my/neotree-hex to open a file path using neo-buffer--get-filename-current-line.
(defun my/neotree-hex
(hexl-find-file neo-buffer--get-filename-current-line))
(with-eval-after-load 'neotree
(define-key neotree-mode-map (kbd "C-c C-x")
'my/neotree-hex))
At the very least, you are missing the (empty) argument list in the function:
(defun my/neotree-hex ()
(hexl-find-file neo-buffer--get-filename-current-line))
I don't know what neo-buffer--get-filename-current-line is: if it is a function, then you are not calling it correctly - in lisp, you call a function by enclosing the (name of the) function and its arguments in parens: (func arg1 arg2 ...)[1]; so if it is a function and it takes no arguments, then your function should probably look like this:
(defun my/neotree-hex ()
(interactive)
(hexl-find-file (neo-buffer--get-filename-current-line)))
In order to be able to bind it to a key, you have to make your function a command, which means that you need to add the (interactive) form.
Disclaimer: I know nothing about neotree.
[1] You might want to read an introduction to lisp. One (specifically tailored to Emasc Lisp) is included with the emacs documentation, but is also available online. Eventually, you will want to read the Emacs Lisp Reference Manual. Calling a function is covered in the Introduction and is covered in detail in the Reference.

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.

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.

Why is (commandp '(customize-option 'foo)) nil?

I want to bind customize-option for a certain variable to a key, since I need to change it rather often. I have two options:
(global-set-key (kbd "<f12>") '(lambda() (interactive) (customize-option 'my-variable) ) )
(global-set-key (kbd "<f12>") '(customize-option 'my-variable )
The first one works, the second does not, because commandp complains that customize-option is not a command. Why? As far as I know, customize-option is an interactive function, so commandp should be t:
customize-option is an interactive compiled Lisp function.
It is bound to .
(customize-option SYMBOL)
Customize SYMBOL, which must be a user option variable.
It is the form (customize-option 'my-variable) which is not a command. You cannot bind to an arbitrary quoted form, any more than you can bind to a literal string or an unbound symbol. Some of those would be useful to bind to, but it's not hard to work around the limitations. Write a macro if you find it hard to live with. (As the saying goes, now you have two problems.)
The second argument to global-set-key must be a command definition, typically a symbol naming an interactive function. An interactive function is a function that begins with the (interactive) form. For example:
(defun delete-to-end ()
"Delete text from point to the end of buffer."
(interactive)
(delete-region (point) (point-max)))
This defines an interactive function and assigns it to the symbol delete-to-end. After that, delete-to-end is a valid command that you can pass to global-set-key:
(global-set-key [f12] 'delete-to-end)
Without the (interactive) line, delete-to-end would still name a function callable from Lisp programs, but it would not be a "command". Since it is marked interactive, (commandp 'delete-to-end) returns true, and M-x delete-to-end works.
Interactive functions don't need to be bound to a symbol, they can be anonymous. Like any other anonymous functions, they are created using a lambda form, except that for commands it must also include (interactive). Anonymous commands can be passed as the second argument to global-set-key without assigning them to a symbol, so the following definition is equivalent to the one above:
(global-set-key [f12]
(lambda ()
"Delete text from point to the end of buffer."
(interactive)
(delete-region (point) (point-max))))
...except it's somewhat less readable, and looks uglier when inspected with C-h c
or C-h k.
In your case, the first call to global-set-key is given a valid command (a quoted lambda form is itself a valid function), but the second one isn't, it is given a two-element list that can neither be called nor satisfies the requirement of being marked "interactive".

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"