Bruno Barbier <brubar...@gmail.com> writes: > Arthur Miller <arthur.mil...@live.com> writes: > >> Bruno Barbier <brubar...@gmail.com> writes: >> >>> Arthur Miller <arthur.mil...@live.com> writes: >>> >>> The hook `org-capture-mode-hook' will be run in your special >>> capture buffer. You can override the "C-c C-c" binding only there. >> >> Yes and in every other capture buffer > > No. If you modify the hook only during your call to 'org-capture', it > will be called only once in your buffer. > >>> Even if I could let bind the function at the right time, I would avoid >>> that solution, as I can't garantuee that this global hack will not break >>> other parts of Emacs (other captures, output filters, threads, timers, >>> etc.). >> >> Why do you think it will break other parts? This is not a global hack, on >> contrary it >> exactly tries to prevent to be "global" in entire Emacs, by let-binding a >> name >> to a local lambda, which becomes "global" only in that buffer. If that >> explains. > > You are assigning a local value to the global binding. Everything in > Emacs will use your functions until you exit the cl-letf. It's like if > you were using 'fset'.
Yes, you are totally correct; unfortunately binding with cl-flet or cl-labels, does not work, so binding the global is the only one that works. > Here is an example that uses cl-letf. Note that the call to > async-shell-command is outside the "local" binding, yet, the cl-letf > breaks it. You should try this in an other Emacs, just in case. > > (defun oops () > (let ((v (async-shell-command "date" "!sh async"))) > (cl-letf > (((symbol-function 'comint-output-filter) > (lambda (proc string) > (message "async-shell-command is using my binding: %s" string) > (read-string "What's the password?")))) > (read-string "what: ") > ))) > (oops) Yes, I definitely agree with you about the concerns, which are certainly valid, but you would get same effect with advice, it is not different at all. The difference is that let-binding is automatically removed and installed, and only active during the cl-letf, while advice is manually installed and active until manually removed. It is not about the tool, but what you do with the tool. >> Here is another version on the same theme, where I don't think you could >> modify the local >> environment without let-binding at all: >> >> #+begin_src emacs-lisp >> (defun my-read-string (prompt) >> (let ((delta 20 ) >> (minibuffer-mode-map org-mode-map)) >> (window-resize (minibuffer-window) delta) >> (cl-letf (((symbol-function 'org-ctrl-c-ctrl-c) >> (lambda () >> (interactive) >> (let ((s (buffer-string))) >> (exit-minibuffer) s))) >> ((symbol-function 'minibuffer-mode) #'org-mode) >> ((symbol-function 'minibuffer-complete-and-exit) #'org-return) >> ((symbol-function 'org-kill-note-or-show-branches) >> #'keyboard-escape-quit)) >> (read-string (concat "# Press C-c C-c to continue, C-c C-k to >> cancel\n# " prompt "\n\n"))))) >> #+end_src > > I hope I've convinced you to not do that. I definitely will not try it, > as Emacs needs a working minibuffer for plenty of things: debugging, > saving, quitting, etc. Your minibuffer will continue to work during and after that function. If you don't use recursive minibuffer, that will only affect the internal buffer created by read-string. If recursive minibuffer is enabled, yes they will also be affected. Of course, there is no reason for you to try that, that was just an example, but I feel a bit of passive aggressivity here, for no good reason tbh. >> read-string is written in C and creates its own minibuffer, which is deleted >> by >> the time read-string exits. I don't know of any other way to cutomize exactly >> *that* minibuffer, without installing a hook or advising some functions, >> which I >> think is way less clean and much more "global" than just running the >> function in >> a local environment. As I understand, let binding for this purpose is a >> normal >> technique in lisps, but I am not an expert as said; I am actually >> experimenting >> with this for the purpose of learning and seeing what is possible. > > Yes, let binding is fundamental. But I think it's the first time I see > 'cl-letf' with the 'symbol-function' place. https://nullprogram.com/blog/2017/10/27/ https://endlessparentheses.com/understanding-letf-and-how-it-replaces-flet.html https://stackoverflow.com/questions/39550578/in-emacs-what-is-the-difference-between-cl-flet-and-cl-letf >> but I am not sure if I can do anything here without introducing at-least an >> extra keymap, to not install into the org-capture-mode-map, so I can as well >> create a minor mode, but at this point it is not much different than >> re-invinting the read-string, so I'll terminate my experiment here :). > > You can replace the buffer keymap with a keymap that only contain your custom > keys, and inherits everything else from org-capture-mode-map. Isn't that what I wrote: introducing an extra keymap? Of course I can solve the problem differently, but that was not what question was about :). >> But I wouldn't speak in some generic terms like "use hooks" or "advise" >> instead >> of let-binding. > > I didn't mean to say to not use let bindings. I'm trying to say that > using 'fset' (i.e. cl-letf + the symbol-function place) looks like a > really bad idea to me. Well, I definitely understand you, and agree that overwriting function for everyone and everything is not the best idea, but unfortunately bindings work as they do in Emacs. I would prefer to have a local binding, with cl-flet, but this does not work in Emacs: (defun my-read-string (prompt) (let ((delta 20 ) (minibuffer-mode-map org-mode-map)) (window-resize (minibuffer-window) delta) (cl-flet ((org-ctrl-c-ctrl-c () (interactive) (let ((s (buffer-string))) (exit-minibuffer) s)) (minibuffer-mode () #'org-mode) (minibuffer-complete-and-exit () #'org-return) (org-kill-note-or-show-branches () #'keyboard-escape-quit)) (read-string (concat "# Press C-c C-c to continue, C-c C-k to cancel\n# " prompt "\n\n"))))) > And, in this case, hooks and adivces are what is > usually used. Hooks serve a different purpose. Advice can serve same purpose with exactly same side effect, and some other limitations. With some care, let-binding is still more "local" then advice. With other words, I agree with you about the problems, but not with dogmatic approach that it should never be done, and that hooks and advices are the replacement. >> (defun org-project-new-project () >> (interactive) >> (let ((org-capture-templates org-project-templates)) >> (org-capture))) >> >> ... > >> I don't know what would be the alternative, but let-binding on >> org-capture-templates, let me clearly re-use the functionality without >> polluting >> the global org-capture-templates variable and without re-implementing pretty >> much anything. > > That looks to me like a perfect use of a let binding. You bind a dynamic > *variable* using *let*, and, that variable is rebound, and used, during, and > only during 'org-capture'. > > > >> I am very interested to hear more on the topic, since I would definitely >> like to >> learn more about different techniques. > > Variables are designed to be overriden (let bounds). Functions are not I have never heard before that functions are not designed to be overriden. I think of them as two slots in a symbol structure; let creates bindings for value slot, and flet for function slot. Functions are just objects or data as any other value in lisp. > (as there is only one binding at any given time). Yes, unfortunately, in Emacs it is so; but I don't think it should be :). There is an interesting package by Nick Ferrier https://github.com/nicferrier/emacs-noflet but it does not seem to work, at least not for me. regards /a