Protesilaos

Emacs: dired-preview version 0.7.0

This is a simple package to automatically preview in a window the file at point in Dired buffers. Preview windows are closed when they are no longer relevant, while preview buffers are killed if they have not been used for other purposes beside previewing. The package provides several customisation options to control its behaviour.

Below are the release notes

Version 0.7.0 on 2026-09-18

This version introduces a few refinements to an already stable code base.

The dired-preview-ignored-extensions-regexp becomes dired-preview-ignored-extensions

This change reflects the broadened flexibility of the user option. Before, it used to accept either a nil value or a regular expression (i.e. a single string). In addition to these, it can now accept a list of strings, each of which represents a file type extension.

The default value is basically this:

;; Illustration of the new value
(setq dired-preview-ignored-extensions
      '("mkv" "webm" "mp4"
        "mp3" "ogg" "m4a" "flac" "wav"
        "gz" "zst" "tar" "xz" "rar" "zip" "iso"
        "epub" "pdf"
        ".DS_Store"))

And here is how it used to be:

;; Illustration of the old variable and its value
(setq dired-preview-ignored-extensions-regexp
      (concat "\\."
              "\\(mkv\\|webm\\|mp4\\|mp3\\|ogg\\|m4a\\|flac\\|wav"
              "\\|gz\\|zst\\|tar\\|xz\\|rar\\|zip"
              "\\|iso\\|epub\\|pdf\\)\\'"))

Again, the old single regexp is supported, though I think the list is easier to write.

New dired-preview-hook and the dired-preview-with-window macro

The hook is run when a preview is displayed. Functions that need to act with the preview window as current can rely on the macro dired-preview-with-window. Look at the code to get an idea of how the macro is used.

Thanks to dasoju for requesting the hook in issue 32: https://github.com/protesilaos/dired-preview/issues/32.

The dired-preview-find-file and dired-preview-open-dwim are robust

They should always find the underlying file and do the right thing with it. Basically, they should always work if there is a preview window.

The dired-preview-image-extensions-regexp is obsolete

This was a user option since the early days of the package. I left it there by mistake. The manual was not mentioning it but it is possible that users have configured it.

Its new name is dired-preview-image-extensions and it is just a variable (not a “user option”), meaning that users should configure it only if they know what they are doing.

The preview trigger is more robust

It should now work reliably and do what is expected of the preview. I fixed this in response to issue 33 by dasoju: https://github.com/protesilaos/dired-preview/issues/33.

The preview state is handled properly

The preview window is closed when it ought to without affecting the rest of the layout. Unexpected values are also handled gracefully. With regard to the latter, thanks to abdulnafe-t for reporting a bug which helped me notice this problem. The report is part of issue 34: https://github.com/protesilaos/dired-preview/issues/34.

The original value of dired-dwim-target is handled correctly

The dired-dwim-target is changed by the preview so that relevant Dired operations are not affected by the preview window. When we need to restore that variable to its original value, we now do it without hardcoding a preference.

Thanks to qhga for bringing this matter to my attention in issue 36: https://github.com/protesilaos/dired-preview/issues/36.

Previous:
See all: Code blog entries