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(eval-after-load "dired" 
  '(progn
     (define-key dired-mode-map "c" 'dired-create-empty-file)
     (define-key dired-mode-map "r" 'dired-do-compress-to)))

Why is the eval-after-load necessary when this is an init file? From my understanding, it makes it only run when dired is loaded, but isn't the init file also loaded once? I was getting "symbol's value as variable is void" warning for dired-mode-map but it was working fine without.

Is this because the warning is emitted before dired is loaded, but the symbol is resolved by the time emacs is started up?

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4
  • I believe you may have edited it to be that way, from the history.
    – user129393192
    Commented Jul 8, 2023 at 18:33
  • Oh sorry, I copied your code to my Emacs to format it. Perhaps I deleted a word by mistake and rewrote it. Sorry again.
    – shynur
    Commented Jul 8, 2023 at 18:35
  • Ah. I actually had that formatted from emacs. Strange. I have indent-tabs-mode off with the tab-width 4.
    – user129393192
    Commented Jul 8, 2023 at 18:39
  • Note that you should prefer the macro with-eval-after-load over eval-after-load. If you look at its code, you'll see that with-eval-after-load avoids explicit quoting by using lambda. Maybe, that does not play such a great role for the init file which is usually not byte-compiled but for byte-compiled library files, explicitly quoted sexps are not byte-compiled, but lambda-expressions (and sharp-quoted expressions) are. There is more (also about lexical scoping) at discourse.doomemacs.org/t/…
    – Tobias
    Commented Jul 9, 2023 at 1:24

1 Answer 1

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isn't the init file also loaded once?

Yes, it is loaded once. Loaded when you launch Emacs.

See <https://www.gnu.org/software/emacs/manual/html_node/elisp/Startup-Summary.html>.

Why is the eval-after-load necessary when this is an init file?

To make sure that before executing the following code:

(progn
  (define-key dired-mode-map "c" 'dired-create-empty-file)
  (define-key dired-mode-map "r" 'dired-do-compress-to))

variable dired-mode-map has already been defined / set with a value, IOW, to avoid

"symbol's value as variable is void"

After "dired" is loaded, dired-mode-map will get its own value. Since you don't know when dired will be loaded, use eval-after-load is a good choice.

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8
  • I see, but since this is in init and dired will always be loaded by the time I'm typing, it's not incorrect, but it gets a warning since the variable is not defined yet
    – user129393192
    Commented Jul 8, 2023 at 19:09
  • 1
    @user129393192: What do you mean by "dired will always be loaded by the time I'm typing"?
    – shynur
    Commented Jul 8, 2023 at 19:24
  • I mean that wrapping it like this only avoids the warning, but functionality would not be affected ,since the symbol is resolved, by the time I am typing.
    – user129393192
    Commented Jul 8, 2023 at 20:33
  • 1
    @user129393192: What do you mean by "the symbol is resolved"? Variable dired-mode-map is defined in package dired and it is initialized only when Emacs loads that package.
    – shynur
    Commented Jul 8, 2023 at 20:37
  • Yes exactly. I was just saying that by the time I am typing that that package will be loaded, so that's why there was no issues with me using it without eval-after-load in my init.file, except for the warning.
    – user129393192
    Commented Jul 8, 2023 at 20:39

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