Weekly Tips, Tricks, &c. Thread
reddit / emacs

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AutoModerator · 2022-12-28 08:15

This is a thread for smaller, miscellaneous items that might not
warrant a full post on their own.

[See this search for previous "Weekly Tips, Tricks, &c." Threads.](htt
ps://www.reddit.com/r/emacs/search?q=Weekly+tips&restrict_sr=on&sort=n
ew&t=all)

Don't feel constrained in regards to what you post, just keep your
post vaguely, generally on the topic of emacs.

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Pay08 · 2022-12-28 12:10

Is there a way to highlight functions and variables in Common Lisp?
Lisp-mode only highlights macros.

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phr46 · 2022-12-28 14:05

I've been using Emacs to read manga, and image-next-file and image-
previous-file can get a bit slow for large files. I've written these
functions based on them, so that after opening one page, they also
load the next page in a buffer in the background, so that the next
call is just switching to the already loaded buffer:

    (defun phr-image-next-file (&optional n)
      (interactive)
      (unless (derived-mode-p 'image-mode)
        (error "The buffer is not in Image mode"))
      (unless buffer-file-name
        (error "The current image is not associated with a file"))
      (unless n (setq n 1))
      (let ((next (image-mode--next-file buffer-file-name n)))
        (when (stringp next)
          (if-let ((buffer (get-file-buffer next)))
              (switch-to-buffer buffer)
            (find-file next))
          (let ((preload (image-mode--next-file next n)))
            (when (stringp preload)
              (make-thread (lambda () (find-file-noselect
preload))))))))

    (defun phr-image-previous-file (&optional n)
      (interactive)
      (phr-image-next-file (if n (- n) -1)))

If you keep calling `phr-image-next-file`, then you will always be
loading one page ahead.

This can get ugly with a lot of buffers open once you finished
reading, so I use this to close all the buffers from the same folder:

    (defun phr-buffers-from-same-folder (x y)
      (and (buffer-file-name x)
           (buffer-file-name y)
           (equal (file-name-directory (buffer-file-name x))
                  (file-name-directory (buffer-file-name y)))))

    (defun phr-image-close-folder ()
      (interactive)
      (unless (derived-mode-p 'image-mode)
        (error "The buffer is not in Image mode"))
      (unless buffer-file-name
        (error "The current image is not associated with a file"))
      (dolist (buffer (cl-remove-if-not
                        (lambda (b) (phr-buffers-from-same-folder
(current-buffer) b))
                      (buffer-list)))
        (kill-buffer buffer)))

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MitchellMarquez42 · 2022-12-28 18:12

There's a package called "highlight-defined" that works for elisp, it
might work for common lisp too

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00-11 · 2022-12-28 19:06

See [Highlight Lisp
Functions](https://www.emacswiki.org/emacs/HighlightLispFunctions) and
[Highlight Elisp
Variables](https://www.emacswiki.org/emacs/HighlightElispVariables) --
libraries [`hl-
defined.el`](https://www.emacswiki.org/emacs/download/hl-defined.el)
and [`hi-var.el`](https://www.emacswiki.org/emacs/download/hi-var.el).

* The former lets you highlight symbols that are known to be defined
functions and/or variables -- or those that are **not** known to be
such.

* The latter lets you highlight occurrences of variables:
   * User options (face `hivar-options`)
   * Other dynamically scoped variables (face `hivar-dynamic-vars`)
   * File-local variables (face `hivar-file-local-vars`)
   * Other buffer-local variables (face `hivar-buffer-local-vars`)

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Pay08 · 2022-12-28 19:13

Don't those two only work with Emacs Lisp?

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00-11 · 2022-12-28 19:47

Yes, they're designed for Elisp. You can try them with other Lisps,
but no guarantees. They use `emacs-lisp-syntax-table` and check the
Emacs-Lisp current state using tests such as `fboundp`, `boundp`, and
`special-variable-p`, so yeah, they might not get you very far with
another Lisp. And certainly other Lisps won't have things like user
options and file/buffer-local variables.

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Pay08 · 2022-12-28 22:45

Well, it seems to be working.

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00-11 · 2022-12-28 22:51

So much the better! And perhaps someone else will have a more helpful
suggestion.

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lafrenierejm · 2022-12-31 21:19

When opening a SQLite database file via `find-file`, I'd like to start
a new `sql-sqlite` buffer with the selected file as the database. The
only approach I can think of so far is to create my own major mode
that performs the relevant `sql-sqlite` calls, and then add that major
mode to `auto-mode-alist`. Is that a good and reasonable approach, or
is there a simpler way to do what I want?