On Wed, Jun 23, 2021 at 4:56 PM Hongyi Zhao wrote: > > On Wed, Jun 23, 2021 at 3:49 PM Omar Polo wrote: > > > > (sorry for the delay) > > > > Hongyi Zhao writes: > > > > > On Sat, Jun 19, 2021 at 11:57 PM Omar Polo wrote: > > >> > > >> > > >> Hongyi Zhao writes: > > >> > > >> > On Sat, Jun 19, 2021 at 10:48 PM Omar Polo wrote: > > >> >> > > >> >> > > >> >> Hongyi Zhao writes: > > >> >> > > >> >> > Dear all, > > >> >> > > > >> >> > Are there any built-in method of Emacs which can let me conveniently > > >> >> > check/inspect/retrieve the definition/usage of any > > >> >> > commands/symbols/operators used in elisp code at-the-point/in-situ? > > >> >> > Say, for the following code snippets: > > >> >> > > > >> >> > ;;; > > >> >> > (defun fk/company-wordfreq-toggle-language (&optional language) > > >> >> > (interactive) > > >> >> > (setq ispell-local-dictionary (or language > > >> >> > (if (string= > > >> >> > ispell-local-dictionary "english") > > >> >> > "turkish" > > >> >> > "english"))) > > >> >> > [...] > > >> >> > `(progn > > >> >> > ,@(mapcar (lambda (p) `(use-package ,p)) > > >> >> > packages))) > > >> >> > > > >> >> > (use-multiple-packages flycheck > > >> >> > dash > > >> >> > ) > > >> >> > > > >> >> > [...] > > >> >> > (mapcar #'straight-use-package '(flycheck lsp-mode dash ...)) > > >> >> > > > >> >> > ;or equivalently > > >> >> > > > >> >> > (defvar my-package-list '(flycheck lsp-mode dash ...)) > > >> >> > (mapcar #'straight-use-package my-package-list) > > >> >> > ;;; > > >> >> > > > >> >> > I want to find some convenient methods built in Emacs itself with an > > >> >> > in-situ manner - by moving the point to the interest position - to > > >> >> > check any commands/symbols/operators used in them. > > >> >> > > > >> >> > Regards > > >> >> > > >> >> there is M-. (xref-find-definitions) that will jump to the definition of > > >> >> the symbol at point (at least in emacs lisp buffers), > > >> > > > >> > Thank you very much. But still there are some symbols can't find with > > >> > this method, say, #' ,@ ' and so on. > > >> > > >> #' ' ` , and ,@ aren't symbols, they are reader macros, i.e. special > > >> character sequences that the lisp reader expands into some special > > >> constructs. For instance, #'foo is the same as (function 'foo) and 'foo > > >> the same as (quote foo). > > >> > > >> If you M-. with the point over quote (in an elisp buffer) it should jump > > >> to eval.c (assuming you have the C source files available). > > >> > > >> >> and M-, (xref-pop-marker-stack) to jump back. > > >> > > > >> > I use scratch buffer to test, and it can't jump back there. > > >> > > >> M-, is meant to be used after one or more M-. > > >> > > >> For instance: > > >> > > >> 1. in *scratch* type describe-function > > >> 2. press M-. -- it'll jump to help-fns.el.gz > > >> 3. move the point over with-help-window (something like ~10 lines below) > > >> 4. M-. again -- it'll jump to a different place in the same file > > >> 5. go back with M-, -- now you're back in the definition of > > >> describe-function > > >> 6. M-, again -- now you're back in the *scratch* buffer > > > > > > Wonderful explanations. But I still failed to reproduce the M-, , as > > > for the other steps you told above except the last two, I can > > > reproduce them exactly the same as you described. > > > > > > See the attachment for the info I saw on the bottom mini-buffer when > > > hitting M-, (M- comma). > > > > don't want to sound rude, but could you please refrain from attaching a > > whole screenshot just for an error message? Copying the error, like: > > > > "it says that: buffer is read-only" > > > > it's enough IMHO. (you'll find a copy of the error message in the > > *Messages* buffer if you don't want to type it by hand.) > > > > Now, usually that error is signaled when you try to insert something > > into a buffer that read-only. There can be multiple reasons for that, > > but unfortunately I thinks it's something on your end, since I cannot > > reproduce with `emacs -Q'. Make sure that you are hitting M-, and not > > the comma alone, or ensure that M-, is bound to xref-pop-marker-stack > > and not to something else (C-h k M-,) > > Thank you very much. Because of my negligence, the real input sequence > I've tried before is as follows: > > (C-h k M-') Then I put the cursor on the result buffer which describing M-' , then I hit M-' again. Now, the following screenshot will be triggered: [image: 2021-06-23_16-59.png] I hope this time I clearly expressed all of my key sequences. HY > > > > > As en extreme solution, try to enable the debug-on-error (M-x > > toggle-debug-on-error RET) and look at the stacktrace when that error > > happens. (You can use toggle-debug-on-error again to disable it later) > > > > >> > > >> >> > > >> >> Or you can C-h f or C-h v (describe-function/variable) and then M-n > > >> >> (next-history-element) to bring in the symbol at point. > > >> > > > >> > I meet the following message: M-n is undefined, as shown in the > > >> > attached screenshot file. > > >> > > >> M-n should be defined in some minibuffer maps; with `emacs -Q' I can > > >> > > >> C-h v C-h k M-n > > >> > > >> and it tells me that. > > > > > > I got the following with your above command sequence: > > > > > > M-n runs the command next-history-element (found in > > > minibuffer-local-must-match-map), which is an interactive compiled > > > Lisp function in ‘simple.el’. > > > > > > It is bound to , , M-n, > > > . > > > > > > (next-history-element N) > > > > > > Puts next element of the minibuffer history in the minibuffer. > > > With argument N, it uses the Nth following element. The position > > > in the history can go beyond the current position and invoke "future > > > history." > > > > Yep. Sorry for giving a long command sequence without any explanation. > > `C-h v' is describe-variable, it should enter the minibuffer asking for > > a variable to be described. Then `C-h k' is describe-key, that works in > > the minibuffer too. M-n is bound to next-history-element there too, so > > it should work. When you are over (or at the beginning) of a symbol, > > M-n should pull that symbol into the minibuffer. So with the cursor > > over > > > > toggle-debug-on-error > > > > if I type `C-h f' (describe-function) and then M-n, Emacs automatically > > inserts "toggle-debug-on-error" as input in the minibuffer. Then I can > > simply RET to read the documentation of the function :) > > Wonderful. Got it. Thank you very much again. > > HY > > > > > > HY > > > > > >> > > >> > M-n runs the command next-history-element (found in > > >> > minibuffer-local-must-match-map), which is an interactive compiled > > >> > Lisp function in ‘simple.el’. > > >> > > >> Cheers, > > >> > > >> > HY > > >> > > > > > -- > Assoc. Prof. Hongyi Zhao > Theory and Simulation of Materials > Hebei Vocational University of Technology and Engineering > NO. 552 North Gangtie Road, Xingtai, China -- Assoc. Prof. Hongyi Zhao Theory and Simulation of Materials Hebei Vocational University of Technology and Engineering NO. 552 North Gangtie Road, Xingtai, China